Version abc81004

39 files changed, 10024 insertions, 130 deletions

diff --git a/abc.dsp b/abc.dsp
index 8f3cfbe2..9ef7952a 100644
--- a/abc.dsp
+++ b/abc.dsp
@@ -42,7 +42,7 @@ RSC=rc.exe
 # PROP Ignore_Export_Lib 0
 # PROP Target_Dir ""
 # ADD BASE CPP /nologo /W3 /GX /O2 /D "WIN32" /D "NDEBUG" /D "_CONSOLE" /D "_MBCS" /YX /FD /c
-# ADD CPP /nologo /W3 /GX /O2 /I "src/base/abc" /I "src/base/abci" /I "src/base/cmd" /I "src/base/io" /I "src/base/main" /I "src/base/ver" /I "src/bdd/cudd" /I "src/bdd/dsd" /I "src/bdd/epd" /I "src/bdd/mtr" /I "src/bdd/parse" /I "src/bdd/reo" /I "src/bdd/cas" /I "src/map/fpga" /I "src/map/mapper" /I "src/map/mio" /I "src/map/super" /I "src/map/if" /I "src/map/pcm" /I "src/map/ply" /I "src/misc/extra" /I "src/misc/mvc" /I "src/misc/st" /I "src/misc/util" /I "src/misc/espresso" /I "src/misc/nm" /I "src/misc/vec" /I "src/misc/hash" /I "src/misc/bzlib" /I "src/misc/zlib" /I "src/opt/cut" /I "src/opt/dec" /I "src/opt/fxu" /I "src/opt/rwr" /I "src/opt/sim" /I "src/opt/ret" /I "src/opt/res" /I "src/opt/lpk" /I "src/sat/bsat" /I "src/sat/csat" /I "src/sat/msat" /I "src/sat/fraig" /I "src/sat/nsat" /I "src/sat/psat" /I "src/aig/ivy" /I "src/aig/hop" /I "src/aig/rwt" /I "src/aig/deco" /I "src/aig/mem" /I "src/aig/dar" /I "src/aig/fra" /I "src/aig/cnf" /I "src/aig/csw" /I "src/aig/ioa" /I "src/aig/aig" /I "src/aig/kit" /I "src/aig/bdc" /I "src/aig/bar" /I "src/aig/ntl" /I "src/aig/nwk" /I "src/aig/tim" /I "src/opt/mfs" /I "src/aig/mfx" /I "src/aig/saig" /I "src/aig/bbr" /I "src/aig/int" /I "src/aig/dch" /I "src/aig/ssw" /D "WIN32" /D "NDEBUG" /D "_CONSOLE" /D "_MBCS" /D "__STDC__" /D ABC_DLL=DLLEXPORT /D "_CRT_SECURE_NO_DEPRECATE" /D "ABC_USE_LIBRARIES" /FR /YX /FD /c
+# ADD CPP /nologo /W3 /GX /O2 /I "src/base/abc" /I "src/base/abci" /I "src/base/cmd" /I "src/base/io" /I "src/base/main" /I "src/base/ver" /I "src/bdd/cudd" /I "src/bdd/dsd" /I "src/bdd/epd" /I "src/bdd/mtr" /I "src/bdd/parse" /I "src/bdd/reo" /I "src/bdd/cas" /I "src/map/fpga" /I "src/map/mapper" /I "src/map/mio" /I "src/map/super" /I "src/map/if" /I "src/map/pcm" /I "src/map/ply" /I "src/misc/extra" /I "src/misc/mvc" /I "src/misc/st" /I "src/misc/util" /I "src/misc/espresso" /I "src/misc/nm" /I "src/misc/vec" /I "src/misc/hash" /I "src/misc/bzlib" /I "src/misc/zlib" /I "src/opt/cut" /I "src/opt/dec" /I "src/opt/fxu" /I "src/opt/rwr" /I "src/opt/sim" /I "src/opt/ret" /I "src/opt/res" /I "src/opt/lpk" /I "src/sat/bsat" /I "src/sat/csat" /I "src/sat/msat" /I "src/sat/fraig" /I "src/sat/nsat" /I "src/sat/psat" /I "src/aig/ivy" /I "src/aig/hop" /I "src/aig/rwt" /I "src/aig/deco" /I "src/aig/mem" /I "src/aig/dar" /I "src/aig/fra" /I "src/aig/cnf" /I "src/aig/csw" /I "src/aig/ioa" /I "src/aig/aig" /I "src/aig/kit" /I "src/aig/bdc" /I "src/aig/bar" /I "src/aig/ntl" /I "src/aig/nwk" /I "src/aig/tim" /I "src/opt/mfs" /I "src/aig/mfx" /I "src/aig/saig" /I "src/aig/bbr" /I "src/aig/int" /I "src/aig/dch" /I "src/aig/ssw" /I "src/sat/lsat" /I "src/aig/cec" /D "WIN32" /D "NDEBUG" /D "_CONSOLE" /D "_MBCS" /D "__STDC__" /D ABC_DLL=DLLEXPORT /D "_CRT_SECURE_NO_DEPRECATE" /D "ABC_USE_LIBRARIES" /FR /YX /FD /c
 # ADD BASE RSC /l 0x409 /d "NDEBUG"
 # ADD RSC /l 0x409 /d "NDEBUG"
 BSC32=bscmake.exe
@@ -66,7 +66,7 @@ LINK32=link.exe
 # PROP Ignore_Export_Lib 0
 # PROP Target_Dir ""
 # ADD BASE CPP /nologo /W3 /Gm /GX /ZI /Od /D "WIN32" /D "_DEBUG" /D "_CONSOLE" /D "_MBCS" /YX /FD /GZ /c
-# ADD CPP /nologo /W3 /Gm /GX /ZI /Od /I "src/base/abc" /I "src/base/abci" /I "src/base/cmd" /I "src/base/io" /I "src/base/main" /I "src/base/ver" /I "src/bdd/cudd" /I "src/bdd/dsd" /I "src/bdd/epd" /I "src/bdd/mtr" /I "src/bdd/parse" /I "src/bdd/reo" /I "src/bdd/cas" /I "src/map/fpga" /I "src/map/mapper" /I "src/map/mio" /I "src/map/super" /I "src/map/if" /I "src/map/pcm" /I "src/map/ply" /I "src/misc/extra" /I "src/misc/mvc" /I "src/misc/st" /I "src/misc/util" /I "src/misc/espresso" /I "src/misc/nm" /I "src/misc/vec" /I "src/misc/hash" /I "src/misc/bzlib" /I "src/misc/zlib" /I "src/opt/cut" /I "src/opt/dec" /I "src/opt/fxu" /I "src/opt/rwr" /I "src/opt/sim" /I "src/opt/ret" /I "src/opt/res" /I "src/opt/lpk" /I "src/sat/bsat" /I "src/sat/csat" /I "src/sat/msat" /I "src/sat/fraig" /I "src/sat/nsat" /I "src/sat/psat" /I "src/aig/ivy" /I "src/aig/hop" /I "src/aig/rwt" /I "src/aig/deco" /I "src/aig/mem" /I "src/aig/dar" /I "src/aig/fra" /I "src/aig/cnf" /I "src/aig/csw" /I "src/aig/ioa" /I "src/aig/aig" /I "src/aig/kit" /I "src/aig/bdc" /I "src/aig/bar" /I "src/aig/ntl" /I "src/aig/nwk" /I "src/aig/tim" /I "src/opt/mfs" /I "src/aig/mfx" /I "src/aig/saig" /I "src/aig/bbr" /I "src/aig/int" /I "src/aig/dch" /I "src/aig/ssw" /D "WIN32" /D "_DEBUG" /D "_CONSOLE" /D "_MBCS" /D "__STDC__" /D ABC_DLL=DLLEXPORT /D "_CRT_SECURE_NO_DEPRECATE" /D "ABC_USE_LIBRARIES" /FR /YX /FD /GZ /c
+# ADD CPP /nologo /W3 /Gm /GX /ZI /Od /I "src/base/abc" /I "src/base/abci" /I "src/base/cmd" /I "src/base/io" /I "src/base/main" /I "src/base/ver" /I "src/bdd/cudd" /I "src/bdd/dsd" /I "src/bdd/epd" /I "src/bdd/mtr" /I "src/bdd/parse" /I "src/bdd/reo" /I "src/bdd/cas" /I "src/map/fpga" /I "src/map/mapper" /I "src/map/mio" /I "src/map/super" /I "src/map/if" /I "src/map/pcm" /I "src/map/ply" /I "src/misc/extra" /I "src/misc/mvc" /I "src/misc/st" /I "src/misc/util" /I "src/misc/espresso" /I "src/misc/nm" /I "src/misc/vec" /I "src/misc/hash" /I "src/misc/bzlib" /I "src/misc/zlib" /I "src/opt/cut" /I "src/opt/dec" /I "src/opt/fxu" /I "src/opt/rwr" /I "src/opt/sim" /I "src/opt/ret" /I "src/opt/res" /I "src/opt/lpk" /I "src/sat/bsat" /I "src/sat/csat" /I "src/sat/msat" /I "src/sat/fraig" /I "src/sat/nsat" /I "src/sat/psat" /I "src/aig/ivy" /I "src/aig/hop" /I "src/aig/rwt" /I "src/aig/deco" /I "src/aig/mem" /I "src/aig/dar" /I "src/aig/fra" /I "src/aig/cnf" /I "src/aig/csw" /I "src/aig/ioa" /I "src/aig/aig" /I "src/aig/kit" /I "src/aig/bdc" /I "src/aig/bar" /I "src/aig/ntl" /I "src/aig/nwk" /I "src/aig/tim" /I "src/opt/mfs" /I "src/aig/mfx" /I "src/aig/saig" /I "src/aig/bbr" /I "src/aig/int" /I "src/aig/dch" /I "src/aig/ssw" /I "src/sat/lsat" /I "src/aig/cec" /D "WIN32" /D "_DEBUG" /D "_CONSOLE" /D "_MBCS" /D "__STDC__" /D ABC_DLL=DLLEXPORT /D "_CRT_SECURE_NO_DEPRECATE" /D "ABC_USE_LIBRARIES" /FR /YX /FD /GZ /c
 # SUBTRACT CPP /X
 # ADD BASE RSC /l 0x409 /d "_DEBUG"
 # ADD RSC /l 0x409 /d "_DEBUG"
@@ -1261,6 +1261,14 @@ SOURCE=.\src\sat\psat\m114p_types.h
 
 # PROP Default_Filter ""
 # End Group
+# Begin Group "lsat"
+
+# PROP Default_Filter ""
+# Begin Source File
+
+SOURCE=.\src\sat\lsat\solver.h
+# End Source File
+# End Group
 # End Group
 # Begin Group "opt"
 
@@ -3501,6 +3509,10 @@ SOURCE=.\src\aig\ssw\sswSweep.c
 SOURCE=.\src\aig\ssw\sswUnique.c
 # End Source File
 # End Group
+# Begin Group "cec"
+
+# PROP Default_Filter ""
+# End Group
 # End Group
 # End Group
 # Begin Group "Header Files"
diff --git a/src/aig/aig/aig.h b/src/aig/aig/aig.h
index 503985b7..7480df78 100644
--- a/src/aig/aig/aig.h
+++ b/src/aig/aig/aig.h
@@ -194,6 +194,17 @@ struct Aig_ManCut_t_
     unsigned *      puTemp[4];       // used for the truth table computation
 };
 
+#ifdef WIN32
+#define DLLEXPORT __declspec(dllexport)
+#define DLLIMPORT __declspec(dllimport)
+#else  /* defined(WIN32) */
+#define DLLIMPORT
+#endif /* defined(WIN32) */
+
+#ifndef ABC_DLL
+#define ABC_DLL DLLIMPORT
+#endif
+
 static inline Aig_Cut_t *  Aig_ObjCuts( Aig_ManCut_t * p, Aig_Obj_t * pObj )                         { return p->pCuts[pObj->Id];  }
 static inline void         Aig_ObjSetCuts( Aig_ManCut_t * p, Aig_Obj_t * pObj, Aig_Cut_t * pCuts )   { p->pCuts[pObj->Id] = pCuts; }
 
@@ -452,7 +463,7 @@ static inline int     Aig_ObjFanoutNext( Aig_Man_t * p, int iFan )   { assert(iF
 ////////////////////////////////////////////////////////////////////////
 
 /*=== aigCheck.c ========================================================*/
-extern int             Aig_ManCheck( Aig_Man_t * p );
+extern ABC_DLL int     Aig_ManCheck( Aig_Man_t * p );
 extern void            Aig_ManCheckMarkA( Aig_Man_t * p );
 extern void            Aig_ManCheckPhase( Aig_Man_t * p );
 /*=== aigCuts.c ========================================================*/
@@ -502,7 +513,7 @@ extern Aig_Man_t *     Aig_ManFrames( Aig_Man_t * pAig, int nFs, int fInit, int
 extern Aig_Man_t *     Aig_ManStart( int nNodesMax );
 extern Aig_Man_t *     Aig_ManStartFrom( Aig_Man_t * p );
 extern Aig_Man_t *     Aig_ManExtractMiter( Aig_Man_t * p, Aig_Obj_t * pNode1, Aig_Obj_t * pNode2 );
-extern void            Aig_ManStop( Aig_Man_t * p );
+extern ABC_DLL void    Aig_ManStop( Aig_Man_t * p );
 extern int             Aig_ManCleanup( Aig_Man_t * p );
 extern int             Aig_ManAntiCleanup( Aig_Man_t * p );
 extern int             Aig_ManPiCleanup( Aig_Man_t * p );
diff --git a/src/aig/cec/cecSat.c b/src/aig/cec/cecSat.c
new file mode 100644
index 00000000..37f63f05
--- /dev/null
+++ b/src/aig/cec/cecSat.c
@@ -0,0 +1,284 @@
+/**CFile****************************************************************
+
+  FileName    [cecSat.c]
+
+  SystemName  [ABC: Logic synthesis and verification system.]
+
+  PackageName [Combinational equivalence checking.]
+
+  Synopsis    [Backend calling the SAT solver.]
+
+  Author      [Alan Mishchenko]
+  
+  Affiliation [UC Berkeley]
+
+  Date        [Ver. 1.0. Started - June 30, 2007.]
+
+  Revision    [$Id: cecSat.c,v 1.00 2007/06/30 00:00:00 alanmi Exp $]
+
+***********************************************************************/
+
+#include "aig.h"
+#include "cnf.h"
+#include "solver.h"
+
+////////////////////////////////////////////////////////////////////////
+///                        DECLARATIONS                              ///
+////////////////////////////////////////////////////////////////////////
+
+////////////////////////////////////////////////////////////////////////
+///                     FUNCTION DEFINITIONS                         ///
+////////////////////////////////////////////////////////////////////////
+
+/**Function*************************************************************
+
+  Synopsis    [Writes CNF into a file.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+solver * Cnf_WriteIntoSolverNew( Cnf_Dat_t * p )
+{
+    solver * pSat;
+    int i, status;
+    pSat = solver_new();
+    for ( i = 0; i < p->nVars; i++ )
+        solver_newVar( pSat );
+    for ( i = 0; i < p->nClauses; i++ )
+    {
+        if ( !solver_addClause( pSat, p->pClauses[i+1]-p->pClauses[i], p->pClauses[i] ) )
+        {
+            solver_delete( pSat );
+            return NULL;
+        }
+    }
+    status = solver_simplify(pSat);
+    if ( status == 0 )
+    {
+        solver_delete( pSat );
+        return NULL;
+    }
+    return pSat;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Adds the OR-clause.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Cnf_DataWriteAndClausesNew( void * p, Cnf_Dat_t * pCnf )
+{
+/*
+    sat_solver * pSat = p;
+    Aig_Obj_t * pObj;
+    int i, Lit;
+    Aig_ManForEachPo( pCnf->pMan, pObj, i )
+    {
+        Lit = toLitCond( pCnf->pVarNums[pObj->Id], 0 );
+        if ( !sat_solver_addclause( pSat, &Lit, &Lit+1 ) )
+            return 0;
+    }
+*/
+    return 1;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Adds the OR-clause.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Cnf_DataWriteOrClauseNew( solver * pSat, Cnf_Dat_t * pCnf )
+{
+    Aig_Obj_t * pObj;
+    int i, * pLits;
+    pLits = ALLOC( int, Aig_ManPoNum(pCnf->pMan) );
+    Aig_ManForEachPo( pCnf->pMan, pObj, i )
+        pLits[i] = solver_mkLit_args( pCnf->pVarNums[pObj->Id], 0 );
+    if ( !solver_addClause( pSat, Aig_ManPoNum(pCnf->pMan), pLits ) )
+    {
+        free( pLits );
+        return 0;
+    }
+    free( pLits );
+    return 1;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Writes the given clause in a file in DIMACS format.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Sat_SolverPrintStatsNew( FILE * pFile, solver * pSat )
+{
+//    printf( "starts        : %8d\n", solver_num_assigns(pSat) );
+    printf( "vars          : %8d\n", solver_num_vars(pSat) );
+    printf( "clauses       : %8d\n", solver_num_clauses(pSat) );
+    printf( "conflicts     : %8d\n", solver_num_learnts(pSat) );
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Returns a counter-example.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int * Sat_SolverGetModelNew( solver * pSat, int * pVars, int nVars )
+{
+    int * pModel;
+    int i;
+    pModel = ALLOC( int, nVars+1 );
+    for ( i = 0; i < nVars; i++ )
+    {
+        assert( pVars[i] >= 0 && pVars[i] < solver_num_vars(pSat) );
+        pModel[i] = (int)(solver_modelValue_Var( pSat, pVars[i] ) == solver_l_True);
+    }
+    return pModel;    
+}
+
+/**Function*************************************************************
+
+  Synopsis    []
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Cec_RunSat( Aig_Man_t * pMan, sint64 nConfLimit, sint64 nInsLimit, int fFlipBits, int fAndOuts, int fVerbose )
+{
+    solver * pSat;
+    Cnf_Dat_t * pCnf;
+    int status, RetValue, clk = clock();
+    Vec_Int_t * vCiIds;
+
+    assert( Aig_ManRegNum(pMan) == 0 );
+    pMan->pData = NULL;
+
+    // derive CNF
+    pCnf = Cnf_Derive( pMan, Aig_ManPoNum(pMan) );
+//    pCnf = Cnf_DeriveSimple( pMan, Aig_ManPoNum(pMan) );
+
+    // convert into SAT solver
+    pSat = Cnf_WriteIntoSolverNew( pCnf );
+    if ( pSat == NULL )
+    {
+        Cnf_DataFree( pCnf );
+        return 1;
+    }
+
+
+    if ( fAndOuts )
+    {
+        assert( 0 );
+        // assert each output independently
+        if ( !Cnf_DataWriteAndClausesNew( pSat, pCnf ) )
+        {
+            solver_delete( pSat );
+            Cnf_DataFree( pCnf );
+            return 1;
+        }
+    }
+    else
+    {
+        // add the OR clause for the outputs
+        if ( !Cnf_DataWriteOrClauseNew( pSat, pCnf ) )
+        {
+            solver_delete( pSat );
+            Cnf_DataFree( pCnf );
+            return 1;
+        }
+    }
+    vCiIds = Cnf_DataCollectPiSatNums( pCnf, pMan );
+    Cnf_DataFree( pCnf );
+
+
+//    printf( "Created SAT problem with %d variable and %d clauses. ", sat_solver_nvars(pSat), sat_solver_nclauses(pSat) );
+//    PRT( "Time", clock() - clk );
+
+    // simplify the problem
+    clk = clock();
+    status = solver_simplify(pSat);
+//    printf( "Simplified the problem to %d variables and %d clauses. ", sat_solver_nvars(pSat), sat_solver_nclauses(pSat) );
+//    PRT( "Time", clock() - clk );
+    if ( status == 0 )
+    {
+        Vec_IntFree( vCiIds );
+        solver_delete( pSat );
+//        printf( "The problem is UNSATISFIABLE after simplification.\n" );
+        return 1;
+    }
+
+    // solve the miter
+    clk = clock();
+    if ( fVerbose )
+        solver_set_verbosity( pSat, 1 );
+    status = solver_solve( pSat, 0, NULL );
+    if ( status == solver_l_Undef )
+    {
+//        printf( "The problem timed out.\n" );
+        RetValue = -1;
+    }
+    else if ( status == solver_l_True )
+    {
+//        printf( "The problem is SATISFIABLE.\n" );
+        RetValue = 0;
+    }
+    else if ( status == solver_l_False )
+    {
+//        printf( "The problem is UNSATISFIABLE.\n" );
+        RetValue = 1;
+    }
+    else
+        assert( 0 );
+//    PRT( "SAT sat_solver time", clock() - clk );
+//    printf( "The number of conflicts = %d.\n", (int)pSat->sat_solver_stats.conflicts );
+ 
+    // if the problem is SAT, get the counterexample
+    if ( status == solver_l_True )
+    {
+        pMan->pData = Sat_SolverGetModelNew( pSat, vCiIds->pArray, vCiIds->nSize );
+    }
+    // free the sat_solver
+    if ( fVerbose )
+        Sat_SolverPrintStatsNew( stdout, pSat );
+//sat_solver_store_write( pSat, "trace.cnf" );
+//sat_solver_store_free( pSat );
+    solver_delete( pSat );
+    Vec_IntFree( vCiIds );
+    return RetValue;
+}
+
+
+////////////////////////////////////////////////////////////////////////
+///                       END OF FILE                                ///
+////////////////////////////////////////////////////////////////////////
+
diff --git a/src/aig/saig/saig.h b/src/aig/saig/saig.h
index c7a40f96..ddae07e0 100644
--- a/src/aig/saig/saig.h
+++ b/src/aig/saig/saig.h
@@ -94,7 +94,9 @@ extern Aig_Man_t *       Saig_ManReadBlif( char * pFileName );
 extern int               Saig_Interpolate( Aig_Man_t * pAig, Inter_ManParams_t * pPars, int * pDepth );
 /*=== saigMiter.c ==========================================================*/
 extern Aig_Man_t *       Saig_ManCreateMiter( Aig_Man_t * p1, Aig_Man_t * p2, int Oper );
-extern Aig_Man_t *       Saig_ManDupInitZero( Aig_Man_t * p );
+extern Aig_Man_t *       Saig_ManCreateMiterComb( Aig_Man_t * p1, Aig_Man_t * p2, int Oper );
+extern Aig_Man_t *       Saig_ManCreateMiterTwo( Aig_Man_t * pOld, Aig_Man_t * pNew, int nFrames );
+extern int               Saig_ManDemiterSimple( Aig_Man_t * p, Aig_Man_t ** ppAig0, Aig_Man_t ** ppAig1 );
 /*=== saigPhase.c ==========================================================*/
 extern Aig_Man_t *       Saig_ManPhaseAbstract( Aig_Man_t * p, Vec_Int_t * vInits, int nFrames, int fIgnore, int fPrint, int fVerbose );
 /*=== saigRetFwd.c ==========================================================*/
@@ -107,6 +109,8 @@ extern Aig_Man_t *       Saig_ManRetimeMinArea( Aig_Man_t * p, int nMaxIters, in
 extern int               Saig_ManRetimeSteps( Aig_Man_t * p, int nSteps, int fForward, int fAddBugs );
 /*=== saigScl.c ==========================================================*/
 extern void              Saig_ManReportUselessRegisters( Aig_Man_t * pAig );
+/*=== saigSynch.c ==========================================================*/
+extern Aig_Man_t *       Saig_ManDupInitZero( Aig_Man_t * p );
 /*=== saigTrans.c ==========================================================*/
 extern Aig_Man_t *       Saig_ManTimeframeSimplify( Aig_Man_t * pAig, int nFrames, int nFramesMax, int fInit, int fVerbose );
 
diff --git a/src/aig/saig/saigMiter.c b/src/aig/saig/saigMiter.c
index 5b18db6e..5efcd24d 100644
--- a/src/aig/saig/saigMiter.c
+++ b/src/aig/saig/saigMiter.c
@@ -30,7 +30,7 @@
 
 /**Function*************************************************************
 
-  Synopsis    []
+  Synopsis    [Creates sequential miter.]
 
   Description []
                
@@ -39,59 +39,59 @@
   SeeAlso     []
 
 ***********************************************************************/
-Aig_Man_t * Saig_ManCreateMiter( Aig_Man_t * p1, Aig_Man_t * p2, int Oper )
+Aig_Man_t * Saig_ManCreateMiter( Aig_Man_t * p0, Aig_Man_t * p1, int Oper )
 {
     Aig_Man_t * pNew;
     Aig_Obj_t * pObj;
     int i;
-    assert( Saig_ManRegNum(p1) > 0 || Saig_ManRegNum(p2) > 0 );
-    assert( Saig_ManPiNum(p1) == Saig_ManPiNum(p2) );
-    assert( Saig_ManPoNum(p1) == Saig_ManPoNum(p2) );
-    pNew = Aig_ManStart( Aig_ManObjNumMax(p1) + Aig_ManObjNumMax(p2) );
+    assert( Saig_ManRegNum(p0) > 0 || Saig_ManRegNum(p1) > 0 );
+    assert( Saig_ManPiNum(p0) == Saig_ManPiNum(p1) );
+    assert( Saig_ManPoNum(p0) == Saig_ManPoNum(p1) );
+    pNew = Aig_ManStart( Aig_ManObjNumMax(p0) + Aig_ManObjNumMax(p1) );
     pNew->pName = Aig_UtilStrsav( "miter" );
     // map constant nodes
+    Aig_ManConst1(p0)->pData = Aig_ManConst1(pNew);
     Aig_ManConst1(p1)->pData = Aig_ManConst1(pNew);
-    Aig_ManConst1(p2)->pData = Aig_ManConst1(pNew);
     // map primary inputs
-    Saig_ManForEachPi( p1, pObj, i )
+    Saig_ManForEachPi( p0, pObj, i )
         pObj->pData = Aig_ObjCreatePi( pNew );
-    Saig_ManForEachPi( p2, pObj, i )
+    Saig_ManForEachPi( p1, pObj, i )
         pObj->pData = Aig_ManPi( pNew, i );
     // map register outputs
-    Saig_ManForEachLo( p1, pObj, i )
+    Saig_ManForEachLo( p0, pObj, i )
         pObj->pData = Aig_ObjCreatePi( pNew );
-    Saig_ManForEachLo( p2, pObj, i )
+    Saig_ManForEachLo( p1, pObj, i )
         pObj->pData = Aig_ObjCreatePi( pNew );
     // map internal nodes
-    Aig_ManForEachNode( p1, pObj, i )
+    Aig_ManForEachNode( p0, pObj, i )
         pObj->pData = Aig_And( pNew, Aig_ObjChild0Copy(pObj), Aig_ObjChild1Copy(pObj) );
-    Aig_ManForEachNode( p2, pObj, i )
+    Aig_ManForEachNode( p1, pObj, i )
         pObj->pData = Aig_And( pNew, Aig_ObjChild0Copy(pObj), Aig_ObjChild1Copy(pObj) );
     // create primary outputs
-    Saig_ManForEachPo( p1, pObj, i )
+    Saig_ManForEachPo( p0, pObj, i )
     {
         if ( Oper == 0 ) // XOR
-            pObj = Aig_Exor( pNew, Aig_ObjChild0Copy(pObj), Aig_ObjChild0Copy(Aig_ManPo(p2,i)) );
-        else if ( Oper == 1 ) // implication is PO(p1) -> PO(p2)  ...  complement is PO(p1) & !PO(p2) 
-            pObj = Aig_And( pNew, Aig_ObjChild0Copy(pObj), Aig_Not(Aig_ObjChild0Copy(Aig_ManPo(p2,i))) );
+            pObj = Aig_Exor( pNew, Aig_ObjChild0Copy(pObj), Aig_ObjChild0Copy(Aig_ManPo(p1,i)) );
+        else if ( Oper == 1 ) // implication is PO(p0) -> PO(p1)  ...  complement is PO(p0) & !PO(p1) 
+            pObj = Aig_And( pNew, Aig_ObjChild0Copy(pObj), Aig_Not(Aig_ObjChild0Copy(Aig_ManPo(p1,i))) );
         else
             assert( 0 );
         Aig_ObjCreatePo( pNew, pObj );
     }
     // create register inputs
-    Saig_ManForEachLi( p1, pObj, i )
+    Saig_ManForEachLi( p0, pObj, i )
         pObj->pData = Aig_ObjCreatePo( pNew, Aig_ObjChild0Copy(pObj) );
-    Saig_ManForEachLi( p2, pObj, i )
+    Saig_ManForEachLi( p1, pObj, i )
         pObj->pData = Aig_ObjCreatePo( pNew, Aig_ObjChild0Copy(pObj) );
     // cleanup
-    Aig_ManSetRegNum( pNew, Saig_ManRegNum(p1) + Saig_ManRegNum(p2) );
+    Aig_ManSetRegNum( pNew, Saig_ManRegNum(p0) + Saig_ManRegNum(p1) );
     Aig_ManCleanup( pNew );
     return pNew;
 }
 
 /**Function*************************************************************
 
-  Synopsis    [Duplicates the AIG to have constant-0 initial state.]
+  Synopsis    [Creates combinational miter.]
 
   Description []
                
@@ -100,30 +100,569 @@ Aig_Man_t * Saig_ManCreateMiter( Aig_Man_t * p1, Aig_Man_t * p2, int Oper )
   SeeAlso     []
 
 ***********************************************************************/
-Aig_Man_t * Saig_ManDupInitZero( Aig_Man_t * p )
+Aig_Man_t * Saig_ManCreateMiterComb( Aig_Man_t * p0, Aig_Man_t * p1, int Oper )
 {
     Aig_Man_t * pNew;
     Aig_Obj_t * pObj;
     int i;
+    assert( Aig_ManPiNum(p0) == Aig_ManPiNum(p1) );
+    assert( Aig_ManPoNum(p0) == Aig_ManPoNum(p1) );
+    pNew = Aig_ManStart( Aig_ManObjNumMax(p0) + Aig_ManObjNumMax(p1) );
+    pNew->pName = Aig_UtilStrsav( "miter" );
+    // map constant nodes
+    Aig_ManConst1(p0)->pData = Aig_ManConst1(pNew);
+    Aig_ManConst1(p1)->pData = Aig_ManConst1(pNew);
+    // map primary inputs and register outputs
+    Aig_ManForEachPi( p0, pObj, i )
+        pObj->pData = Aig_ObjCreatePi( pNew );
+    Aig_ManForEachPi( p1, pObj, i )
+        pObj->pData = Aig_ManPi( pNew, i );
+    // map internal nodes
+    Aig_ManForEachNode( p0, pObj, i )
+        pObj->pData = Aig_And( pNew, Aig_ObjChild0Copy(pObj), Aig_ObjChild1Copy(pObj) );
+    Aig_ManForEachNode( p1, pObj, i )
+        pObj->pData = Aig_And( pNew, Aig_ObjChild0Copy(pObj), Aig_ObjChild1Copy(pObj) );
+    // create primary outputs
+    Aig_ManForEachPo( p0, pObj, i )
+    {
+        if ( Oper == 0 ) // XOR
+            pObj = Aig_Exor( pNew, Aig_ObjChild0Copy(pObj), Aig_ObjChild0Copy(Aig_ManPo(p1,i)) );
+        else if ( Oper == 1 ) // implication is PO(p0) -> PO(p1)  ...  complement is PO(p0) & !PO(p1) 
+            pObj = Aig_And( pNew, Aig_ObjChild0Copy(pObj), Aig_Not(Aig_ObjChild0Copy(Aig_ManPo(p1,i))) );
+        else
+            assert( 0 );
+        Aig_ObjCreatePo( pNew, pObj );
+    }
+    // cleanup
+    Aig_ManSetRegNum( pNew, 0 );
+    Aig_ManCleanup( pNew );
+    return pNew;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Create combinational timeframes by unrolling sequential circuits.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Aig_Man_t * Saig_ManUnrollTwo( Aig_Man_t * pBot, Aig_Man_t * pTop, int nFrames )
+{
+    Aig_Man_t * p, * pAig;
+    Aig_Obj_t * pObj, * pObjLi, * pObjLo;
+    int i, f;
+    assert( nFrames > 1 );
+    assert( Saig_ManPiNum(pBot) == Saig_ManPiNum(pTop) );
+    assert( Saig_ManPoNum(pBot) == Saig_ManPoNum(pTop) );
+    assert( Saig_ManRegNum(pBot) == Saig_ManRegNum(pTop) );
+    assert( Saig_ManRegNum(pBot) > 0 || Saig_ManRegNum(pTop) > 0 );
+    // start timeframes
+    p = Aig_ManStart( nFrames * AIG_MAX(Aig_ManObjNumMax(pBot), Aig_ManObjNumMax(pTop)) );
+    p->pName = Aig_UtilStrsav( "frames" );
+    // create variables for register outputs
+    pAig = pBot;
+    Saig_ManForEachLo( pAig, pObj, i )
+        pObj->pData = Aig_ObjCreatePi( p );
+    // add timeframes
+    for ( f = 0; f < nFrames; f++ )
+    {
+        // create PI nodes for this frame
+        Aig_ManConst1(pAig)->pData = Aig_ManConst1( p );
+        Saig_ManForEachPi( pAig, pObj, i )
+            pObj->pData = Aig_ObjCreatePi( p );
+        // add internal nodes of this frame
+        Aig_ManForEachNode( pAig, pObj, i )
+            pObj->pData = Aig_And( p, Aig_ObjChild0Copy(pObj), Aig_ObjChild1Copy(pObj) );
+        if ( f == nFrames - 1 )
+        {
+            // create POs for this frame
+            Aig_ManForEachPo( pAig, pObj, i )
+                Aig_ObjCreatePo( p, Aig_ObjChild0Copy(pObj) );
+            break;
+        }
+        // save register inputs
+        Saig_ManForEachLi( pAig, pObj, i )
+            pObj->pData = Aig_ObjChild0Copy(pObj);
+        // transfer to register outputs
+        Saig_ManForEachLiLo(  pAig, pObjLi, pObjLo, i )
+            pObjLo->pData = pObjLi->pData;
+        if ( f == 0 )
+        {
+            // transfer from pOld to pNew
+            Saig_ManForEachLo( pAig, pObj, i )
+                Saig_ManLo(pTop, i)->pData = pObj->pData;
+            pAig = pTop;
+        }
+    }
+    Aig_ManCleanup( p );
+    return p;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Duplicates the AIG while creating POs from the set.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Aig_Man_t * Aig_ManDupNodes_old( Aig_Man_t * p, Vec_Ptr_t * vSet )
+{
+    Aig_Man_t * pNew, * pCopy;
+    Aig_Obj_t * pObj;
+    int i;
     pNew = Aig_ManStart( Aig_ManObjNumMax(p) );
     pNew->pName = Aig_UtilStrsav( p->pName );
     Aig_ManConst1(p)->pData = Aig_ManConst1(pNew);
-    Saig_ManForEachPi( p, pObj, i )
+    Aig_ManForEachPi( p, pObj, i )
         pObj->pData = Aig_ObjCreatePi( pNew );
-    Saig_ManForEachLo( p, pObj, i )
-        pObj->pData = Aig_NotCond( Aig_ObjCreatePi( pNew ), pObj->fMarkA );
     Aig_ManForEachNode( p, pObj, i )
         pObj->pData = Aig_And( pNew, Aig_ObjChild0Copy(pObj), Aig_ObjChild1Copy(pObj) );
-    Saig_ManForEachPo( p, pObj, i )
-        pObj->pData = Aig_ObjCreatePo( pNew, Aig_ObjChild0Copy(pObj) );
+//    Saig_ManForEachPo( p, pObj, i )
+//        pObj->pData = Aig_ObjCreatePo( pNew, Aig_ObjChild0Copy(pObj) );
+    Vec_PtrForEachEntry( vSet, pObj, i )
+        Aig_ObjCreatePo( pNew, Aig_NotCond((Aig_Obj_t *)Aig_Regular(pObj)->pData, Aig_IsComplement(pObj)) );
     Saig_ManForEachLi( p, pObj, i )
-        pObj->pData = Aig_ObjCreatePo( pNew, Aig_NotCond( Aig_ObjChild0Copy(pObj), pObj->fMarkA ) );
+        pObj->pData = Aig_ObjCreatePo( pNew, Aig_ObjChild0Copy(pObj) );
     Aig_ManSetRegNum( pNew, Saig_ManRegNum(p) );
-    assert( Aig_ManNodeNum(pNew) == Aig_ManNodeNum(p) );
-    return pNew;
+    // cleanup and return a copy
+    Aig_ManSeqCleanup( pNew );
+    pCopy = Aig_ManDupSimpleDfs( pNew );
+    Aig_ManStop( pNew );
+    return pCopy;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Duplicates the AIG while creating POs from the set.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Aig_Man_t * Aig_ManDupNodes( Aig_Man_t * p, Vec_Ptr_t * vSet, int iPart )
+{
+    Aig_Man_t * pNew, * pCopy;
+    Aig_Obj_t * pObj;
+    int i;
+    Aig_ManCleanData( p );
+    pNew = Aig_ManStart( Aig_ManObjNumMax(p) );
+    pNew->pName = Aig_UtilStrsav( p->pName );
+    Aig_ManConst1(p)->pData = Aig_ManConst1(pNew);
+    Saig_ManForEachPi( p, pObj, i )
+        pObj->pData = Aig_ObjCreatePi( pNew );
+    if ( iPart == 0 )
+    {
+        Saig_ManForEachLo( p, pObj, i )
+            if ( i < Saig_ManRegNum(p)/2 )
+                pObj->pData = Aig_ObjCreatePi( pNew );
+    }
+    else
+    {
+        Saig_ManForEachLo( p, pObj, i )
+            if ( i >= Saig_ManRegNum(p)/2 )
+                pObj->pData = Aig_ObjCreatePi( pNew );
+    }
+    Aig_ManForEachNode( p, pObj, i )
+        if ( Aig_ObjFanin0(pObj)->pData && Aig_ObjFanin1(pObj)->pData )
+            pObj->pData = Aig_And( pNew, Aig_ObjChild0Copy(pObj), Aig_ObjChild1Copy(pObj) );
+//    Saig_ManForEachPo( p, pObj, i )
+//        pObj->pData = Aig_ObjCreatePo( pNew, Aig_ObjChild0Copy(pObj) );
+    Vec_PtrForEachEntry( vSet, pObj, i )
+        Aig_ObjCreatePo( pNew, Aig_NotCond((Aig_Obj_t *)Aig_Regular(pObj)->pData, Aig_IsComplement(pObj)) );
+    if ( iPart == 0 )
+    {
+        Saig_ManForEachLi( p, pObj, i )
+            if ( i < Saig_ManRegNum(p)/2 )
+                pObj->pData = Aig_ObjCreatePo( pNew, Aig_ObjChild0Copy(pObj) );
+    }
+    else
+    {
+        Saig_ManForEachLi( p, pObj, i )
+            if ( i >= Saig_ManRegNum(p)/2 )
+                pObj->pData = Aig_ObjCreatePo( pNew, Aig_ObjChild0Copy(pObj) );
+    }
+    Aig_ManSetRegNum( pNew, Saig_ManRegNum(p)/2 );
+    // cleanup and return a copy
+//    Aig_ManSeqCleanup( pNew );
+    Aig_ManCleanup( pNew );
+    pCopy = Aig_ManDupSimpleDfs( pNew );
+    Aig_ManStop( pNew );
+    return pCopy;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Duplicates the AIG to have constant-0 initial state.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Saig_ManDemiterSimple( Aig_Man_t * p, Aig_Man_t ** ppAig0, Aig_Man_t ** ppAig1 )
+{
+    Vec_Ptr_t * vSet0, * vSet1;
+    Aig_Obj_t * pObj, * pFanin, * pObj0, * pObj1;
+    int i, Counter = 0;
+    assert( Saig_ManRegNum(p) % 2 == 0 );
+    vSet0 = Vec_PtrAlloc( Saig_ManPoNum(p) );
+    vSet1 = Vec_PtrAlloc( Saig_ManPoNum(p) );
+    Saig_ManForEachPo( p, pObj, i )
+    {
+        pFanin = Aig_ObjFanin0(pObj);
+        if ( Aig_ObjIsConst1( pFanin ) )
+        {
+            if ( !Aig_ObjFaninC0(pObj) )
+                printf( "The output number %d of the miter is constant 1.\n", i );
+            Counter++;
+            continue;
+        }
+        if ( !Aig_ObjIsNode(pFanin) || !Aig_ObjRecognizeExor( pFanin, &pObj0, &pObj1 ) )
+        {
+            printf( "The miter cannot be demitered.\n" );
+            Vec_PtrFree( vSet0 );
+            Vec_PtrFree( vSet1 );
+            return 0;
+        }
+//        printf( "%d %d  ", Aig_Regular(pObj0)->Id, Aig_Regular(pObj1)->Id );
+        if ( Aig_Regular(pObj0)->Id < Aig_Regular(pObj1)->Id )
+        {
+            Vec_PtrPush( vSet0, pObj0 );
+            Vec_PtrPush( vSet1, pObj1 );
+        }
+        else
+        {
+            Vec_PtrPush( vSet0, pObj1 );
+            Vec_PtrPush( vSet1, pObj0 );
+        }
+    }
+//    printf( "Miter has %d constant outputs.\n", Counter );
+//    printf( "\n" );
+    if ( ppAig0 )
+    {
+        *ppAig0 = Aig_ManDupNodes( p, vSet0, 0 );
+        FREE( (*ppAig0)->pName );
+        (*ppAig0)->pName = Aig_UtilStrsav( "part0" );
+    }
+    if ( ppAig1 )
+    {
+        *ppAig1 = Aig_ManDupNodes( p, vSet1, 1 );
+        FREE( (*ppAig1)->pName );
+        (*ppAig1)->pName = Aig_UtilStrsav( "part1" );
+    }
+    Vec_PtrFree( vSet0 );
+    Vec_PtrFree( vSet1 );
+    return 1;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Labels logic reachable from the node.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Saig_ManDemiterLabel_rec( Aig_Man_t * p, Aig_Obj_t * pObj, int Value )
+{
+    if ( Aig_ObjIsTravIdCurrent(p, pObj) )
+        return;
+    Aig_ObjSetTravIdCurrent(p, pObj);
+    if ( Value ) 
+        pObj->fMarkB = 1;
+    else
+        pObj->fMarkA = 1;
+    if ( Saig_ObjIsPi(p, pObj) )
+        return;
+    if ( Saig_ObjIsLo(p, pObj) )
+    {
+        Saig_ManDemiterLabel_rec( p, Aig_ObjFanin0( Saig_ObjLoToLi(p, pObj) ), Value );
+        return;
+    }
+    assert( Aig_ObjIsNode(pObj) );
+    Saig_ManDemiterLabel_rec( p, Aig_ObjFanin0(pObj), Value );
+    Saig_ManDemiterLabel_rec( p, Aig_ObjFanin1(pObj), Value );
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Returns the first labeled register encountered during traversal.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Aig_Obj_t * Saig_ManGetLabeledRegister_rec( Aig_Man_t * p, Aig_Obj_t * pObj )
+{
+    Aig_Obj_t * pResult;
+    if ( Aig_ObjIsTravIdCurrent(p, pObj) )
+        return NULL;
+    Aig_ObjSetTravIdCurrent(p, pObj);
+    if ( Saig_ObjIsPi(p, pObj) )
+        return NULL;
+    if ( Saig_ObjIsLo(p, pObj) )
+    {
+        if ( pObj->fMarkA || pObj->fMarkB )
+            return pObj;
+        return Saig_ManGetLabeledRegister_rec( p, Aig_ObjFanin0( Saig_ObjLoToLi(p, pObj) ) );
+    }
+    assert( Aig_ObjIsNode(pObj) );
+    pResult = Saig_ManGetLabeledRegister_rec( p, Aig_ObjFanin0(pObj) );
+    if ( pResult )
+        return pResult;
+    return Saig_ManGetLabeledRegister_rec( p, Aig_ObjFanin1(pObj) );
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Duplicates the AIG to have constant-0 initial state.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Saig_ManDemiter( Aig_Man_t * p, Aig_Man_t ** ppAig0, Aig_Man_t ** ppAig1 )
+{
+    Vec_Ptr_t * vPairs, * vSet0, * vSet1;
+    Aig_Obj_t * pObj, * pObj0, * pObj1, * pFlop0, * pFlop1;
+    int i, Counter;
+    assert( Saig_ManRegNum(p) > 0 );
+    Aig_ManSetPioNumbers( p );
+    // check if demitering is possible
+    vPairs = Vec_PtrAlloc( 2 * Saig_ManPoNum(p) );
+    Saig_ManForEachPo( p, pObj, i )
+    {
+        if ( !Aig_ObjRecognizeExor( Aig_ObjFanin0(pObj), &pObj0, &pObj1 ) )
+        {
+            Vec_PtrFree( vPairs );
+            return 0;
+        }
+        Vec_PtrPush( vPairs, pObj0 );
+        Vec_PtrPush( vPairs, pObj1 );
+    }
+    // start array of outputs
+    vSet0 = Vec_PtrAlloc( Saig_ManPoNum(p) );
+    vSet1 = Vec_PtrAlloc( Saig_ManPoNum(p) );
+    // get the first pair of outputs
+    pObj0 = Vec_PtrEntry( vPairs, 0 );
+    pObj1 = Vec_PtrEntry( vPairs, 1 );
+    // label registers reachable from the outputs
+    Aig_ManIncrementTravId( p );
+    Saig_ManDemiterLabel_rec( p, Aig_Regular(pObj0), 0 );
+    Vec_PtrPush( vSet0, pObj0 );
+    Aig_ManIncrementTravId( p );
+    Saig_ManDemiterLabel_rec( p, Aig_Regular(pObj1), 1 );
+    Vec_PtrPush( vSet1, pObj1 );
+    // find where each output belongs
+    for ( i = 2; i < Vec_PtrSize(vPairs); i += 2 )
+    {
+        pObj0 = Vec_PtrEntry( vPairs, i   );
+        pObj1 = Vec_PtrEntry( vPairs, i+1 );
+
+        Aig_ManIncrementTravId( p );
+        pFlop0 = Saig_ManGetLabeledRegister_rec( p, Aig_Regular(pObj0) );
+
+        Aig_ManIncrementTravId( p );
+        pFlop1 = Saig_ManGetLabeledRegister_rec( p, Aig_Regular(pObj1) );
+
+        if ( (pFlop0->fMarkA && pFlop0->fMarkB) || (pFlop1->fMarkA && pFlop1->fMarkB) || 
+             (pFlop0->fMarkA && pFlop1->fMarkA) || (pFlop0->fMarkB && pFlop1->fMarkB)  )
+            printf( "Ouput pair %4d: Difficult case...\n", i/2 );
+
+        if ( pFlop0->fMarkB )
+        {
+            Saig_ManDemiterLabel_rec( p, pObj0, 1 );
+            Vec_PtrPush( vSet0, pObj0 );
+        }
+        else // if ( pFlop0->fMarkA ) or none
+        {
+            Saig_ManDemiterLabel_rec( p, pObj0, 0 );
+            Vec_PtrPush( vSet1, pObj0 );
+        }
+
+        if ( pFlop1->fMarkB )
+        {
+            Saig_ManDemiterLabel_rec( p, pObj1, 1 );
+            Vec_PtrPush( vSet0, pObj1 );
+        }
+        else // if ( pFlop1->fMarkA ) or none
+        {
+            Saig_ManDemiterLabel_rec( p, pObj1, 0 );
+            Vec_PtrPush( vSet1, pObj1 );
+        }
+    }
+    // check if there are any flops in common
+    Counter = 0;
+    Saig_ManForEachLo( p, pObj, i )
+        if ( pObj->fMarkA && pObj->fMarkB )
+            Counter++;
+    if ( Counter > 0 )
+        printf( "The miters contains %d flops reachable from both AIGs.\n", Counter );
+
+    // produce two miters
+    if ( ppAig0 )
+    {
+        assert( 0 );
+        *ppAig0 = Aig_ManDupNodes( p, vSet0, 0 ); // not ready
+        FREE( (*ppAig0)->pName );
+        (*ppAig0)->pName = Aig_UtilStrsav( "part0" );
+    }
+    if ( ppAig1 )
+    {
+        assert( 0 );
+        *ppAig1 = Aig_ManDupNodes( p, vSet1, 1 ); // not ready
+        FREE( (*ppAig1)->pName );
+        (*ppAig1)->pName = Aig_UtilStrsav( "part1" );
+    }
+    Vec_PtrFree( vSet0 );
+    Vec_PtrFree( vSet1 );
+    Vec_PtrFree( vPairs );
+    return 1;
 }
 
 
+/**Function*************************************************************
+
+  Synopsis    [Create specialized miter by unrolling two circuits.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Aig_Man_t * Saig_ManCreateMiterTwo( Aig_Man_t * pOld, Aig_Man_t * pNew, int nFrames )
+{
+    Aig_Man_t * pFrames0, * pFrames1, * pMiter;
+    assert( Aig_ManNodeNum(pOld) <= Aig_ManNodeNum(pNew) );
+    pFrames0 = Saig_ManUnrollTwo( pOld, pOld, nFrames );
+    pFrames1 = Saig_ManUnrollTwo( pNew, pOld, nFrames );
+    pMiter = Saig_ManCreateMiterComb( pFrames0, pFrames1, 0 );
+    Aig_ManStop( pFrames0 );
+    Aig_ManStop( pFrames1 );
+    return pMiter;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Reduces SEC to CEC for the special case of seq synthesis.]
+
+  Description [The first circuit (pPart0) should be circuit before synthesis.
+  The second circuit (pPart1) should be circuit after synthesis.]
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Ssw_SecSpecial( Aig_Man_t * pPart0, Aig_Man_t * pPart1, int fVerbose )
+{
+    extern int Fra_FraigCec( Aig_Man_t ** ppAig, int nConfLimit, int fVerbose );
+    int nFrames = 2;   // modify to enable comparison over any number of frames
+    Aig_Man_t * pMiterCec;
+    int RetValue, clkTotal = clock();
+//    assert( Aig_ManNodeNum(pPart0) <= Aig_ManNodeNum(pPart1) );
+    if ( Aig_ManNodeNum(pPart0) >= Aig_ManNodeNum(pPart1) )
+    {
+        printf( "Warning: The design after synthesis is smaller!\n" );
+        printf( "This warning may indicate that the order of designs is changed.\n" );
+        printf( "The solver expects the original disign as first argument and\n" );
+        printf( "the modified design as the second argument in Ssw_SecSpecial().\n" );
+    }
+    // create two-level miter
+    pMiterCec = Saig_ManCreateMiterTwo( pPart0, pPart1, nFrames );
+    if ( fVerbose )
+    {
+        Aig_ManPrintStats( pMiterCec );
+//        Aig_ManDumpBlif( pMiterCec, "miter01.blif", NULL, NULL );
+//        printf( "The new miter is written into file \"%s\".\n", "miter01.blif" );
+    }
+    // run CEC on this miter
+    RetValue = Fra_FraigCec( &pMiterCec, 100000, fVerbose );
+    // transfer model if given
+//    if ( pNtk2 == NULL )
+//        pNtk1->pModel = pMiterCec->pData, pMiterCec->pData = NULL;
+    Aig_ManStop( pMiterCec );
+    // report the miter
+    if ( RetValue == 1 )
+    {
+        printf( "Networks are equivalent.   " );
+PRT( "Time", clock() - clkTotal );
+    }
+    else if ( RetValue == 0 )
+    {
+        printf( "Networks are NOT EQUIVALENT.   " );
+PRT( "Time", clock() - clkTotal );
+    }
+    else
+    {
+        printf( "Networks are UNDECIDED.   " );
+PRT( "Time", clock() - clkTotal );
+    }
+    fflush( stdout );
+    return RetValue;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Reduces SEC to CEC for the special case of seq synthesis.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Ssw_SecSpecialMiter( Aig_Man_t * pMiter, int fVerbose )
+{
+    Aig_Man_t * pPart0, * pPart1;
+    int RetValue;
+    if ( fVerbose )
+        Aig_ManPrintStats( pMiter );
+    // demiter the miter
+    if ( !Saig_ManDemiterSimple( pMiter, &pPart0, &pPart1 ) )
+    {
+        printf( "Demitering has failed.\n" );
+        return -1;
+    }
+    if ( fVerbose )
+    {
+        Aig_ManPrintStats( pPart0 );
+        Aig_ManPrintStats( pPart1 );
+//        Aig_ManDumpBlif( pPart0, "part0.blif", NULL, NULL );
+//        Aig_ManDumpBlif( pPart1, "part1.blif", NULL, NULL );
+//        printf( "The result of demitering is written into files \"%s\" and \"%s\".\n", "part0.blif", "part1.blif" );
+    }
+    RetValue = Ssw_SecSpecial( pPart0, pPart1, fVerbose );
+    Aig_ManStop( pPart0 );
+    Aig_ManStop( pPart1 );
+    return RetValue;
+}
+
 ////////////////////////////////////////////////////////////////////////
 ///                       END OF FILE                                ///
 ////////////////////////////////////////////////////////////////////////
diff --git a/src/aig/saig/saigSynch.c b/src/aig/saig/saigSynch.c
index 9dbbb420..eb0fefc9 100644
--- a/src/aig/saig/saigSynch.c
+++ b/src/aig/saig/saigSynch.c
@@ -453,6 +453,40 @@ Vec_Str_t * Saig_SynchSequence( Aig_Man_t * pAig, int nWords )
 
 /**Function*************************************************************
 
+  Synopsis    [Duplicates the AIG to have constant-0 initial state.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Aig_Man_t * Saig_ManDupInitZero( Aig_Man_t * p )
+{
+    Aig_Man_t * pNew;
+    Aig_Obj_t * pObj;
+    int i;
+    pNew = Aig_ManStart( Aig_ManObjNumMax(p) );
+    pNew->pName = Aig_UtilStrsav( p->pName );
+    Aig_ManConst1(p)->pData = Aig_ManConst1(pNew);
+    Saig_ManForEachPi( p, pObj, i )
+        pObj->pData = Aig_ObjCreatePi( pNew );
+    Saig_ManForEachLo( p, pObj, i )
+        pObj->pData = Aig_NotCond( Aig_ObjCreatePi( pNew ), pObj->fMarkA );
+    Aig_ManForEachNode( p, pObj, i )
+        pObj->pData = Aig_And( pNew, Aig_ObjChild0Copy(pObj), Aig_ObjChild1Copy(pObj) );
+    Saig_ManForEachPo( p, pObj, i )
+        pObj->pData = Aig_ObjCreatePo( pNew, Aig_ObjChild0Copy(pObj) );
+    Saig_ManForEachLi( p, pObj, i )
+        pObj->pData = Aig_ObjCreatePo( pNew, Aig_NotCond( Aig_ObjChild0Copy(pObj), pObj->fMarkA ) );
+    Aig_ManSetRegNum( pNew, Saig_ManRegNum(p) );
+    assert( Aig_ManNodeNum(pNew) == Aig_ManNodeNum(p) );
+    return pNew;
+}
+
+/**Function*************************************************************
+
   Synopsis    [Determines synchronizing sequence using ternary simulation.]
 
   Description []
diff --git a/src/aig/ssw/ssw.h b/src/aig/ssw/ssw.h
index 766407d4..e6e3a1b4 100644
--- a/src/aig/ssw/ssw.h
+++ b/src/aig/ssw/ssw.h
@@ -55,6 +55,7 @@ struct Ssw_Pars_t_
     int              fSemiFormal;   // enable semiformal filtering
     int              fUniqueness;   // enable uniqueness constraints
     int              fVerbose;      // verbose stats
+    int              fFlopVerbose;  // verbose printout of redundant flops
     // optimized latch correspondence
     int              fLatchCorrOpt; // perform register correspondence (optimized)
     int              nSatVarMax;    // max number of SAT vars before recycling SAT solver (optimized latch corr only)
@@ -92,6 +93,8 @@ extern Aig_Man_t *   Ssw_SignalCorrespondence( Aig_Man_t * pAig, Ssw_Pars_t * pP
 extern Aig_Man_t *   Ssw_LatchCorrespondence( Aig_Man_t * pAig, Ssw_Pars_t * pPars );
 /*=== sswLoc.c ==========================================================*/
 extern int           Saig_ManLocalization( Aig_Man_t * p, int nFramesMax, int nConfMax, int fVerbose );
+/*=== sswMiter.c ===================================================*/
+extern int           Ssw_SecSpecialMiter( Aig_Man_t * pMiter, int fVerbose );
 /*=== sswPart.c ==========================================================*/
 extern Aig_Man_t *   Ssw_SignalCorrespondencePart( Aig_Man_t * pAig, Ssw_Pars_t * pPars );
 /*=== sswPairs.c ===================================================*/
diff --git a/src/aig/ssw/sswPart.c b/src/aig/ssw/sswPart.c
index 7eb6b8fe..983a2022 100644
--- a/src/aig/ssw/sswPart.c
+++ b/src/aig/ssw/sswPart.c
@@ -97,12 +97,14 @@ Aig_Man_t * Ssw_SignalCorrespondencePart( Aig_Man_t * pAig, Ssw_Pars_t * pPars )
         if ( pAig->vOnehots )
             pTemp->vOnehots = Aig_ManRegProjectOnehots( pAig, pTemp, pAig->vOnehots, fVerbose );
         // run SSW
-        pNew = Ssw_SignalCorrespondence( pTemp, pPars );
-        nClasses = Aig_TransferMappedClasses( pAig, pTemp, pMapBack );
-        if ( fVerbose )
-            printf( "%3d : Reg = %4d. PI = %4d. (True = %4d. Regs = %4d.) And = %5d. It = %3d. Cl = %5d.\n", 
-                i, Vec_IntSize(vPart), Aig_ManPiNum(pTemp)-Vec_IntSize(vPart), nCountPis, nCountRegs, Aig_ManNodeNum(pTemp), pPars->nIters, nClasses );
-        Aig_ManStop( pNew );
+        if (nCountPis>0) {
+            pNew = Ssw_SignalCorrespondence( pTemp, pPars );
+            nClasses = Aig_TransferMappedClasses( pAig, pTemp, pMapBack );
+            if ( fVerbose )
+                printf( "%3d : Reg = %4d. PI = %4d. (True = %4d. Regs = %4d.) And = %5d. It = %3d. Cl = %5d.\n", 
+                    i, Vec_IntSize(vPart), Aig_ManPiNum(pTemp)-Vec_IntSize(vPart), nCountPis, nCountRegs, Aig_ManNodeNum(pTemp), pPars->nIters, nClasses );
+            Aig_ManStop( pNew );
+        }
         Aig_ManStop( pTemp );
         free( pMapBack );
     }
diff --git a/src/aig/ssw_old/module.make b/src/aig/ssw_old/module.make
new file mode 100644
index 00000000..625d72d1
--- /dev/null
+++ b/src/aig/ssw_old/module.make
@@ -0,0 +1,14 @@
+SRC +=    src/aig/ssw/sswAig.c \
+    src/aig/ssw/sswBmc.c \
+    src/aig/ssw/sswClass.c \
+    src/aig/ssw/sswCnf.c \
+    src/aig/ssw/sswCore.c \
+    src/aig/ssw/sswLcorr.c \
+    src/aig/ssw/sswMan.c \
+    src/aig/ssw/sswPart.c \
+    src/aig/ssw/sswPairs.c \
+    src/aig/ssw/sswSat.c \
+    src/aig/ssw/sswSim.c \
+    src/aig/ssw/sswSimSat.c \
+    src/aig/ssw/sswSweep.c \
+    src/aig/ssw/sswUnique.c
diff --git a/src/aig/ssw_old/ssw.h b/src/aig/ssw_old/ssw.h
new file mode 100644
index 00000000..766407d4
--- /dev/null
+++ b/src/aig/ssw_old/ssw.h
@@ -0,0 +1,117 @@
+/**CFile****************************************************************
+
+  FileName    [ssw.h] 
+
+  SystemName  [ABC: Logic synthesis and verification system.]
+
+  PackageName [Inductive prover with constraints.]
+
+  Synopsis    [External declarations.]
+
+  Author      [Alan Mishchenko]
+  
+  Affiliation [UC Berkeley]
+
+  Date        [Ver. 1.0. Started - September 1, 2008.]
+
+  Revision    [$Id: ssw.h,v 1.00 2008/09/01 00:00:00 alanmi Exp $]
+
+***********************************************************************/
+ 
+#ifndef __SSW_H__
+#define __SSW_H__
+
+#ifdef __cplusplus
+extern "C" { 
+#endif
+
+////////////////////////////////////////////////////////////////////////
+///                          INCLUDES                                ///
+////////////////////////////////////////////////////////////////////////
+
+////////////////////////////////////////////////////////////////////////
+///                         PARAMETERS                               ///
+////////////////////////////////////////////////////////////////////////
+
+////////////////////////////////////////////////////////////////////////
+///                         BASIC TYPES                              ///
+////////////////////////////////////////////////////////////////////////
+
+// choicing parameters
+typedef struct Ssw_Pars_t_ Ssw_Pars_t;
+struct Ssw_Pars_t_
+{
+    int              nPartSize;     // size of the partition
+    int              nOverSize;     // size of the overlap between partitions
+    int              nFramesK;      // the induction depth
+    int              nFramesAddSim; // the number of additional frames to simulate
+    int              nConstrs;      // treat the last nConstrs POs as seq constraints
+    int              nMaxLevs;      // the max number of levels of nodes to consider
+    int              nBTLimit;      // conflict limit at a node
+    int              nMinDomSize;   // min clock domain considered for optimization
+    int              fPolarFlip;    // uses polarity adjustment
+    int              fSkipCheck;    // do not run equivalence check for unaffected cones
+    int              fLatchCorr;    // perform register correspondence
+    int              fSemiFormal;   // enable semiformal filtering
+    int              fUniqueness;   // enable uniqueness constraints
+    int              fVerbose;      // verbose stats
+    // optimized latch correspondence
+    int              fLatchCorrOpt; // perform register correspondence (optimized)
+    int              nSatVarMax;    // max number of SAT vars before recycling SAT solver (optimized latch corr only)
+    int              nRecycleCalls; // calls to perform before recycling SAT solver (optimized latch corr only)
+    // internal parameters
+    int              nIters;        // the number of iterations performed
+};
+
+// sequential counter-example
+typedef struct Ssw_Cex_t_   Ssw_Cex_t;
+struct Ssw_Cex_t_
+{
+    int              iPo;               // the zero-based number of PO, for which verification failed
+    int              iFrame;            // the zero-based number of the time-frame, for which verificaiton failed
+    int              nRegs;             // the number of registers in the miter 
+    int              nPis;              // the number of primary inputs in the miter
+    int              nBits;             // the number of words of bit data used
+    unsigned         pData[0];          // the cex bit data (the number of bits: nRegs + (iFrame+1) * nPis)
+};
+
+////////////////////////////////////////////////////////////////////////
+///                      MACRO DEFINITIONS                           ///
+////////////////////////////////////////////////////////////////////////
+
+////////////////////////////////////////////////////////////////////////
+///                    FUNCTION DECLARATIONS                         ///
+////////////////////////////////////////////////////////////////////////
+
+/*=== sswAbs.c ==========================================================*/
+extern Aig_Man_t *   Saig_ManProofAbstraction( Aig_Man_t * p, int nFrames, int nConfMax, int fVerbose );
+/*=== sswCore.c ==========================================================*/
+extern void          Ssw_ManSetDefaultParams( Ssw_Pars_t * p );
+extern void          Ssw_ManSetDefaultParamsLcorr( Ssw_Pars_t * p );
+extern Aig_Man_t *   Ssw_SignalCorrespondence( Aig_Man_t * pAig, Ssw_Pars_t * pPars );
+extern Aig_Man_t *   Ssw_LatchCorrespondence( Aig_Man_t * pAig, Ssw_Pars_t * pPars );
+/*=== sswLoc.c ==========================================================*/
+extern int           Saig_ManLocalization( Aig_Man_t * p, int nFramesMax, int nConfMax, int fVerbose );
+/*=== sswPart.c ==========================================================*/
+extern Aig_Man_t *   Ssw_SignalCorrespondencePart( Aig_Man_t * pAig, Ssw_Pars_t * pPars );
+/*=== sswPairs.c ===================================================*/
+extern int           Ssw_SecWithPairs( Aig_Man_t * pAig1, Aig_Man_t * pAig2, Vec_Int_t * vIds1, Vec_Int_t * vIds2, Ssw_Pars_t * pPars );
+extern int           Ssw_SecGeneral( Aig_Man_t * pAig1, Aig_Man_t * pAig2, Ssw_Pars_t * pPars );
+extern int           Ssw_SecGeneralMiter( Aig_Man_t * pMiter, Ssw_Pars_t * pPars );
+/*=== sswSim.c ===================================================*/
+extern Ssw_Cex_t *   Ssw_SmlAllocCounterExample( int nRegs, int nRealPis, int nFrames );
+extern void          Ssw_SmlFreeCounterExample( Ssw_Cex_t * pCex );
+extern int           Ssw_SmlRunCounterExample( Aig_Man_t * pAig, Ssw_Cex_t * p );
+extern int           Ssw_SmlFindOutputCounterExample( Aig_Man_t * pAig, Ssw_Cex_t * p );
+extern Ssw_Cex_t *   Ssw_SmlDupCounterExample( Ssw_Cex_t * p, int nRegsNew );
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
+
+////////////////////////////////////////////////////////////////////////
+///                       END OF FILE                                ///
+////////////////////////////////////////////////////////////////////////
+
diff --git a/src/aig/ssw_old/sswAig.c b/src/aig/ssw_old/sswAig.c
new file mode 100644
index 00000000..7b6d1bb0
--- /dev/null
+++ b/src/aig/ssw_old/sswAig.c
@@ -0,0 +1,205 @@
+/**CFile****************************************************************
+
+  FileName    [sswAig.c]
+
+  SystemName  [ABC: Logic synthesis and verification system.]
+
+  PackageName [Inductive prover with constraints.]
+
+  Synopsis    [AIG manipulation.]
+
+  Author      [Alan Mishchenko]
+  
+  Affiliation [UC Berkeley]
+
+  Date        [Ver. 1.0. Started - September 1, 2008.]
+
+  Revision    [$Id: sswAig.c,v 1.00 2008/09/01 00:00:00 alanmi Exp $]
+
+***********************************************************************/
+
+#include "sswInt.h"
+
+////////////////////////////////////////////////////////////////////////
+///                        DECLARATIONS                              ///
+////////////////////////////////////////////////////////////////////////
+
+////////////////////////////////////////////////////////////////////////
+///                     FUNCTION DEFINITIONS                         ///
+////////////////////////////////////////////////////////////////////////
+
+/**Function*************************************************************
+
+  Synopsis    [Performs speculative reduction for one node.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+static inline void Ssw_FramesConstrainNode( Ssw_Man_t * p, Aig_Man_t * pFrames, Aig_Man_t * pAig, Aig_Obj_t * pObj, int iFrame, int fTwoPos )
+{
+    Aig_Obj_t * pObjNew, * pObjNew2, * pObjRepr, * pObjReprNew, * pMiter;
+    // skip nodes without representative
+    pObjRepr = Aig_ObjRepr(pAig, pObj);
+    if ( pObjRepr == NULL )
+        return;
+    p->nConstrTotal++;
+    assert( pObjRepr->Id < pObj->Id );
+    // get the new node 
+    pObjNew = Ssw_ObjFrame( p, pObj, iFrame );
+    // get the new node of the representative
+    pObjReprNew = Ssw_ObjFrame( p, pObjRepr, iFrame );
+    // if this is the same node, no need to add constraints
+    if ( pObj->fPhase == pObjRepr->fPhase )
+    {
+        assert( pObjNew != Aig_Not(pObjReprNew) );
+        if ( pObjNew == pObjReprNew )
+            return;
+    }
+    else
+    {
+        assert( pObjNew != pObjReprNew );
+        if ( pObjNew == Aig_Not(pObjReprNew) )
+            return;
+    }
+    p->nConstrReduced++;
+    // these are different nodes - perform speculative reduction
+    pObjNew2 = Aig_NotCond( pObjReprNew, pObj->fPhase ^ pObjRepr->fPhase );
+    // set the new node
+    Ssw_ObjSetFrame( p, pObj, iFrame, pObjNew2 );
+    // add the constraint
+    if ( fTwoPos )
+    {
+        Aig_ObjCreatePo( pFrames, pObjNew2 );
+        Aig_ObjCreatePo( pFrames, pObjNew );
+    }
+    else
+    {
+        pMiter = Aig_Exor( pFrames, pObjNew, pObjNew2 );
+        Aig_ObjCreatePo( pFrames, Aig_NotCond(pMiter, Aig_ObjPhaseReal(pMiter)) );
+    }
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Prepares the inductive case with speculative reduction.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Aig_Man_t * Ssw_FramesWithClasses( Ssw_Man_t * p )
+{
+    Aig_Man_t * pFrames;
+    Aig_Obj_t * pObj, * pObjLi, * pObjLo, * pObjNew;
+    int i, f;
+    assert( p->pFrames == NULL );
+    assert( Aig_ManRegNum(p->pAig) > 0 );
+    assert( Aig_ManRegNum(p->pAig) < Aig_ManPiNum(p->pAig) );
+    p->nConstrTotal = p->nConstrReduced = 0;
+
+    // start the fraig package
+    pFrames = Aig_ManStart( Aig_ManObjNumMax(p->pAig) * p->nFrames );
+    // create latches for the first frame
+    Saig_ManForEachLo( p->pAig, pObj, i )
+        Ssw_ObjSetFrame( p, pObj, 0, Aig_ObjCreatePi(pFrames) );
+    // add timeframes
+    for ( f = 0; f < p->pPars->nFramesK; f++ )
+    {
+        // map constants and PIs
+        Ssw_ObjSetFrame( p, Aig_ManConst1(p->pAig), f, Aig_ManConst1(pFrames) );
+        Saig_ManForEachPi( p->pAig, pObj, i )
+            Ssw_ObjSetFrame( p, pObj, f, Aig_ObjCreatePi(pFrames) );
+        // set the constraints on the latch outputs
+        Saig_ManForEachLo( p->pAig, pObj, i )
+            Ssw_FramesConstrainNode( p, pFrames, p->pAig, pObj, f, 1 );
+        // add internal nodes of this frame
+        Aig_ManForEachNode( p->pAig, pObj, i )
+        {
+            pObjNew = Aig_And( pFrames, Ssw_ObjChild0Fra(p, pObj, f), Ssw_ObjChild1Fra(p, pObj, f) );
+            Ssw_ObjSetFrame( p, pObj, f, pObjNew );
+            Ssw_FramesConstrainNode( p, pFrames, p->pAig, pObj, f, 1 );
+        }
+        // transfer latch input to the latch outputs 
+        Saig_ManForEachLiLo( p->pAig, pObjLi, pObjLo, i )
+            Ssw_ObjSetFrame( p, pObjLo, f+1, Ssw_ObjChild0Fra(p, pObjLi,f) );
+    }
+    // add the POs for the latch outputs of the last frame
+//    Saig_ManForEachLo( p->pAig, pObj, i )
+//        Aig_ObjCreatePo( pFrames, Ssw_ObjFrame( p, pObj, p->pPars->nFramesK ) );
+    for ( f = 0; f <= p->pPars->nFramesK; f++ )
+        Saig_ManForEachLo( p->pAig, pObj, i )
+            Aig_ObjCreatePo( pFrames, Ssw_ObjFrame( p, pObj, f ) );
+
+    // remove dangling nodes
+    Aig_ManCleanup( pFrames );
+    // make sure the satisfying assignment is node assigned
+    assert( pFrames->pData == NULL );
+//Aig_ManShow( pFrames, 0, NULL );
+    return pFrames;
+}
+
+
+
+/**Function*************************************************************
+
+  Synopsis    [Prepares the inductive case with speculative reduction.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Aig_Man_t * Ssw_SpeculativeReduction( Ssw_Man_t * p )
+{
+    Aig_Man_t * pFrames;
+    Aig_Obj_t * pObj, * pObjNew;
+    int i;
+    assert( p->pFrames == NULL );
+    assert( Aig_ManRegNum(p->pAig) > 0 );
+    assert( Aig_ManRegNum(p->pAig) < Aig_ManPiNum(p->pAig) );
+    p->nConstrTotal = p->nConstrReduced = 0;
+
+    // start the fraig package
+    pFrames = Aig_ManStart( Aig_ManObjNumMax(p->pAig) * p->nFrames );
+    // map constants and PIs
+    Ssw_ObjSetFrame( p, Aig_ManConst1(p->pAig), 0, Aig_ManConst1(pFrames) );
+    Saig_ManForEachPi( p->pAig, pObj, i )
+        Ssw_ObjSetFrame( p, pObj, 0, Aig_ObjCreatePi(pFrames) );
+    // create latches for the first frame
+    Saig_ManForEachLo( p->pAig, pObj, i )
+        Ssw_ObjSetFrame( p, pObj, 0, Aig_ObjCreatePi(pFrames) );
+    // set the constraints on the latch outputs
+    Saig_ManForEachLo( p->pAig, pObj, i )
+        Ssw_FramesConstrainNode( p, pFrames, p->pAig, pObj, 0, 0 );
+    // add internal nodes of this frame
+    Aig_ManForEachNode( p->pAig, pObj, i )
+    {
+        pObjNew = Aig_And( pFrames, Ssw_ObjChild0Fra(p, pObj, 0), Ssw_ObjChild1Fra(p, pObj, 0) );
+        Ssw_ObjSetFrame( p, pObj, 0, pObjNew );
+        Ssw_FramesConstrainNode( p, pFrames, p->pAig, pObj, 0, 0 );
+    }
+    // add the POs for the latch outputs of the last frame
+    Saig_ManForEachLi( p->pAig, pObj, i )
+        Aig_ObjCreatePo( pFrames, Ssw_ObjChild0Fra(p, pObj,0) );
+    // remove dangling nodes
+    Aig_ManCleanup( pFrames );
+    Aig_ManSetRegNum( pFrames, Aig_ManRegNum(p->pAig) );
+    printf( "SpecRed: Total constraints = %d. Reduced constraints = %d.\n", 
+        p->nConstrTotal, p->nConstrReduced );
+    return pFrames;
+}
+
+////////////////////////////////////////////////////////////////////////
+///                       END OF FILE                                ///
+////////////////////////////////////////////////////////////////////////
+
+
diff --git a/src/aig/ssw_old/sswBmc.c b/src/aig/ssw_old/sswBmc.c
new file mode 100644
index 00000000..e2d47440
--- /dev/null
+++ b/src/aig/ssw_old/sswBmc.c
@@ -0,0 +1,315 @@
+/**CFile****************************************************************
+
+  FileName    [sswBmc.c]
+
+  SystemName  [ABC: Logic synthesis and verification system.]
+
+  PackageName [Inductive prover with constraints.]
+
+  Synopsis    [Bounded model checker for equivalence clases.]
+
+  Author      [Alan Mishchenko]
+  
+  Affiliation [UC Berkeley]
+
+  Date        [Ver. 1.0. Started - September 1, 2008.]
+
+  Revision    [$Id: sswBmc.c,v 1.00 2008/09/01 00:00:00 alanmi Exp $]
+
+***********************************************************************/
+
+#include "sswInt.h"
+
+////////////////////////////////////////////////////////////////////////
+///                        DECLARATIONS                              ///
+////////////////////////////////////////////////////////////////////////
+
+typedef struct Ssw_Bmc_t_ Ssw_Bmc_t; // BMC manager
+
+struct Ssw_Bmc_t_
+{
+    // parameters
+    int              nConfMaxStart;  // the starting conflict limit
+    int              nConfMax;       // the intermediate conflict limit
+    int              nFramesSweep;   // the number of frames to sweep
+    int              fVerbose;       // prints output statistics
+    // equivalences considered
+    Ssw_Man_t *      pMan;           // SAT sweeping manager
+    Vec_Ptr_t *      vTargets;       // the nodes that are watched
+    // storage for patterns
+    int              nPatternsAlloc; // the max number of interesting states
+    int              nPatterns;      // the number of patterns
+    Vec_Ptr_t *      vPatterns;      // storage for the interesting states
+    Vec_Int_t *      vHistory;       // what state and how many steps
+};
+
+////////////////////////////////////////////////////////////////////////
+///                     FUNCTION DEFINITIONS                         ///
+////////////////////////////////////////////////////////////////////////
+
+/**Function*************************************************************
+
+  Synopsis    []
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Ssw_Bmc_t * Ssw_BmcManStart( Ssw_Man_t * pMan, int nConfMax, int fVerbose )
+{
+    Ssw_Bmc_t * p;
+    Aig_Obj_t * pObj;
+    int i;
+    // create interpolation manager
+    p = ALLOC( Ssw_Bmc_t, 1 ); 
+    memset( p, 0, sizeof(Ssw_Bmc_t) );
+    p->nConfMaxStart  = nConfMax;
+    p->nConfMax       = nConfMax;
+    p->nFramesSweep   = AIG_MAX( (1<<21)/Aig_ManNodeNum(pMan->pAig), pMan->nFrames );
+    p->fVerbose       = fVerbose;
+    // equivalences considered
+    p->pMan           = pMan;
+    p->vTargets       = Vec_PtrAlloc( Saig_ManPoNum(p->pMan->pAig) );
+    Saig_ManForEachPo( p->pMan->pAig, pObj, i )
+        Vec_PtrPush( p->vTargets, Aig_ObjFanin0(pObj) );
+    // storage for patterns
+    p->nPatternsAlloc = 512;
+    p->nPatterns      = 1;
+    p->vPatterns      = Vec_PtrAllocSimInfo( Aig_ManRegNum(p->pMan->pAig), Aig_BitWordNum(p->nPatternsAlloc) );
+    Vec_PtrCleanSimInfo( p->vPatterns, 0, Aig_BitWordNum(p->nPatternsAlloc) );
+    p->vHistory       = Vec_IntAlloc( 100 );
+    Vec_IntPush( p->vHistory, 0 );
+    // update arrays of the manager
+    free( p->pMan->pNodeToFrames );
+    Vec_IntFree( p->pMan->vSatVars );
+    p->pMan->pNodeToFrames = CALLOC( Aig_Obj_t *, Aig_ManObjNumMax(p->pMan->pAig) * p->nFramesSweep );
+    p->pMan->vSatVars      = Vec_IntStart( Aig_ManObjNumMax(p->pMan->pAig) * (p->nFramesSweep+1) );
+    return p;
+}
+
+/**Function*************************************************************
+
+  Synopsis    []
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ssw_BmcManStop( Ssw_Bmc_t * p )
+{
+    Vec_PtrFree( p->vTargets );
+    Vec_PtrFree( p->vPatterns );
+    Vec_IntFree( p->vHistory );
+    free( p );
+}
+
+/**Function*************************************************************
+
+  Synopsis    []
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Ssw_BmcCheckTargets( Ssw_Bmc_t * p )
+{
+    Aig_Obj_t * pObj;
+    int i;
+    Vec_PtrForEachEntry( p->vTargets, pObj, i )
+        if ( !Ssw_ObjIsConst1Cand(p->pMan->pAig, pObj) )
+            return 1;
+    return 0;
+}
+
+/**Function*************************************************************
+
+  Synopsis    []
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ssw_ManFilterBmcSavePattern( Ssw_Bmc_t * p )
+{
+    unsigned * pInfo;
+    Aig_Obj_t * pObj;
+    int i;
+    if ( p->nPatterns >= p->nPatternsAlloc )
+        return;
+    Saig_ManForEachLo( p->pMan->pAig, pObj, i )
+    {
+        pInfo = Vec_PtrEntry( p->vPatterns, i );
+        if ( Aig_InfoHasBit( p->pMan->pPatWords, Saig_ManPiNum(p->pMan->pAig) + i ) )
+            Aig_InfoSetBit( pInfo, p->nPatterns );
+    }
+    p->nPatterns++;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Performs fraiging for the internal nodes.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Ssw_ManFilterBmc( Ssw_Bmc_t * pBmc, int iPat, int fCheckTargets )
+{
+    Ssw_Man_t * p = pBmc->pMan;
+    Aig_Obj_t * pObj, * pObjNew, * pObjLi, * pObjLo;
+    unsigned * pInfo;
+    int i, f, clk, RetValue, fFirst = 0;
+clk = clock();
+
+    // start initialized timeframes
+    p->pFrames = Aig_ManStart( Aig_ManObjNumMax(p->pAig) * 3 );
+    Saig_ManForEachLo( p->pAig, pObj, i )
+    {
+        pInfo = Vec_PtrEntry( pBmc->vPatterns, i );
+        pObjNew = Aig_NotCond( Aig_ManConst1(p->pFrames), !Aig_InfoHasBit(pInfo, iPat) );
+        Ssw_ObjSetFrame( p, pObj, 0, pObjNew );
+    }
+
+    // sweep internal nodes
+    Ssw_ManStartSolver( p );
+    RetValue = pBmc->nFramesSweep;
+    for ( f = 0; f < pBmc->nFramesSweep; f++ )
+    {
+        // map constants and PIs
+        Ssw_ObjSetFrame( p, Aig_ManConst1(p->pAig), f, Aig_ManConst1(p->pFrames) );
+        Saig_ManForEachPi( p->pAig, pObj, i )
+            Ssw_ObjSetFrame( p, pObj, f, Aig_ObjCreatePi(p->pFrames) );
+        // sweep internal nodes
+        Aig_ManForEachNode( p->pAig, pObj, i )
+        {
+            pObjNew = Aig_And( p->pFrames, Ssw_ObjChild0Fra(p, pObj, f), Ssw_ObjChild1Fra(p, pObj, f) );
+            Ssw_ObjSetFrame( p, pObj, f, pObjNew );
+            if ( Ssw_ManSweepNode( p, pObj, f, 1 ) )
+            {
+                Ssw_ManFilterBmcSavePattern( pBmc );
+                if ( fFirst == 0 )
+                {
+                    fFirst = 1;
+                    pBmc->nConfMax *= 10;
+                } 
+            }
+            if ( f > 0 && p->pSat->stats.conflicts >= pBmc->nConfMax )
+            {
+                RetValue = -1;
+                break;
+            }
+        }
+        // quit if this is the last timeframe
+        if ( p->pSat->stats.conflicts >= pBmc->nConfMax )
+        {
+            RetValue += f + 1;
+            break;
+        }
+        if ( fCheckTargets && Ssw_BmcCheckTargets( pBmc ) )
+            break;
+        // transfer latch input to the latch outputs 
+        // build logic cones for register outputs
+        Saig_ManForEachLiLo( p->pAig, pObjLi, pObjLo, i )
+        {
+            pObjNew = Ssw_ObjChild0Fra(p, pObjLi,f);
+            Ssw_ObjSetFrame( p, pObjLo, f+1, pObjNew );
+            Ssw_CnfNodeAddToSolver( p, Aig_Regular(pObjNew) );
+        }
+//printf( "Frame %2d : Conflicts = %6d. \n", f, p->pSat->stats.conflicts );
+    }
+    if ( fFirst )
+        pBmc->nConfMax /= 10;
+
+    // cleanup
+    Ssw_ClassesCheck( p->ppClasses );
+p->timeBmc += clock() - clk;
+    return RetValue;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Returns 1 if one of the targets has failed.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Ssw_FilterUsingBmc( Ssw_Man_t * pMan, int fCheckTargets, int nConfMax, int fVerbose )
+{
+    Ssw_Bmc_t * p;
+    int RetValue, Frames, Iter, clk = clock();
+    p = Ssw_BmcManStart( pMan, nConfMax, fVerbose );
+    if ( fCheckTargets && Ssw_BmcCheckTargets( p ) )
+    {
+        assert( 0 );
+        Ssw_BmcManStop( p );
+        return 1;
+    }
+    if ( fVerbose )
+    {
+        printf( "AIG : Const = %6d. Cl = %6d. Nodes = %6d.  ConfMax = %6d. FramesMax = %6d.\n", 
+            Ssw_ClassesCand1Num(p->pMan->ppClasses), Ssw_ClassesClassNum(p->pMan->ppClasses), 
+            Aig_ManNodeNum(p->pMan->pAig), p->nConfMax, p->nFramesSweep );
+    } 
+    RetValue = 0;
+    for ( Iter = 0; Iter < p->nPatterns; Iter++ )
+    {
+clk = clock();
+        Frames = Ssw_ManFilterBmc( p, Iter, fCheckTargets );
+        if ( fVerbose )
+        {
+            printf( "%3d : Const = %6d. Cl = %6d. NR = %6d. F = %3d. C = %5d. P = %3d. %s ", 
+                Iter, Ssw_ClassesCand1Num(p->pMan->ppClasses), Ssw_ClassesClassNum(p->pMan->ppClasses), 
+                Aig_ManNodeNum(p->pMan->pFrames), Frames, (int)p->pMan->pSat->stats.conflicts, p->nPatterns, 
+                p->pMan->nSatFailsReal? "f" : " " );
+            PRT( "T", clock() - clk );
+        } 
+        Ssw_ManCleanup( p->pMan );
+        if ( fCheckTargets && Ssw_BmcCheckTargets( p ) )
+        {
+            printf( "Target is hit!!!\n" );
+            RetValue = 1;
+        }
+        if ( p->nPatterns >= p->nPatternsAlloc )
+            break;
+    }
+    Ssw_BmcManStop( p );
+
+    pMan->nStrangers = 0;
+    pMan->nSatCalls = 0;
+    pMan->nSatProof = 0;
+    pMan->nSatFailsReal = 0; 
+    pMan->nSatFailsTotal = 0;
+    pMan->nSatCallsUnsat = 0;
+    pMan->nSatCallsSat = 0;  
+    pMan->timeSimSat = 0;    
+    pMan->timeSat = 0;       
+    pMan->timeSatSat = 0;    
+    pMan->timeSatUnsat = 0;  
+    pMan->timeSatUndec = 0;  
+    return RetValue;
+}
+
+////////////////////////////////////////////////////////////////////////
+///                       END OF FILE                                ///
+////////////////////////////////////////////////////////////////////////
+
+
diff --git a/src/aig/ssw_old/sswClass.c b/src/aig/ssw_old/sswClass.c
new file mode 100644
index 00000000..cfbb138c
--- /dev/null
+++ b/src/aig/ssw_old/sswClass.c
@@ -0,0 +1,941 @@
+/**CFile****************************************************************
+
+  FileName    [sswClass.c]
+
+  SystemName  [ABC: Logic synthesis and verification system.]
+
+  PackageName [Inductive prover with constraints.]
+
+  Synopsis    [Representation of candidate equivalence classes.]
+
+  Author      [Alan Mishchenko]
+  
+  Affiliation [UC Berkeley]
+
+  Date        [Ver. 1.0. Started - September 1, 2008.]
+
+  Revision    [$Id: sswClass.c,v 1.00 2008/09/01 00:00:00 alanmi Exp $]
+
+***********************************************************************/
+
+#include "sswInt.h"
+
+/*
+    The candidate equivalence classes are stored as a vector of pointers 
+    to the array of pointers to the nodes in each class.
+    The first node of the class is its representative node.
+    The representative has the smallest topological order among the class nodes.
+    The nodes inside each class are ordered according to their topological order.
+    The classes are ordered according to the topo order of their representatives.
+*/
+
+// internal representation of candidate equivalence classes
+struct Ssw_Cla_t_
+{
+    // class information
+    Aig_Man_t *      pAig;             // original AIG manager
+    Aig_Obj_t ***    pId2Class;        // non-const classes by ID of repr node
+    int *            pClassSizes;      // sizes of each equivalence class
+    // statistics
+    int              nClasses;         // the total number of non-const classes
+    int              nCands1;          // the total number of const candidates
+    int              nLits;            // the number of literals in all classes
+    // memory
+    Aig_Obj_t **     pMemClasses;      // memory allocated for equivalence classes
+    Aig_Obj_t **     pMemClassesFree;  // memory allocated for equivalence classes to be used
+    // temporary data
+    Vec_Ptr_t *      vClassOld;        // old equivalence class after splitting
+    Vec_Ptr_t *      vClassNew;        // new equivalence class(es) after splitting
+    Vec_Ptr_t *      vRefined;         // the nodes refined since the last iteration
+    // procedures used for class refinement
+    void *           pManData;
+    unsigned (*pFuncNodeHash) (void *,Aig_Obj_t *);              // returns hash key of the node
+    int (*pFuncNodeIsConst)   (void *,Aig_Obj_t *);              // returns 1 if the node is a constant
+    int (*pFuncNodesAreEqual) (void *,Aig_Obj_t *, Aig_Obj_t *); // returns 1 if nodes are equal up to a complement
+};
+
+////////////////////////////////////////////////////////////////////////
+///                        DECLARATIONS                              ///
+////////////////////////////////////////////////////////////////////////
+
+static inline Aig_Obj_t *  Ssw_ObjNext( Aig_Obj_t ** ppNexts, Aig_Obj_t * pObj )                       { return ppNexts[pObj->Id];  }
+static inline void         Ssw_ObjSetNext( Aig_Obj_t ** ppNexts, Aig_Obj_t * pObj, Aig_Obj_t * pNext ) { ppNexts[pObj->Id] = pNext; }
+
+// iterator through the equivalence classes
+#define Ssw_ManForEachClass( p, ppClass, i )                 \
+    for ( i = 0; i < Aig_ManObjNumMax(p->pAig); i++ )        \
+        if ( ((ppClass) = p->pId2Class[i]) == NULL ) {} else
+// iterator through the nodes in one class
+#define Ssw_ClassForEachNode( p, pRepr, pNode, i )           \
+    for ( i = 0; i < p->pClassSizes[pRepr->Id]; i++ )        \
+        if ( ((pNode) = p->pId2Class[pRepr->Id][i]) == NULL ) {} else
+
+////////////////////////////////////////////////////////////////////////
+///                     FUNCTION DEFINITIONS                         ///
+////////////////////////////////////////////////////////////////////////
+
+/**Function*************************************************************
+
+  Synopsis    [Creates one equivalence class.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+static inline void Ssw_ObjAddClass( Ssw_Cla_t * p, Aig_Obj_t * pRepr, Aig_Obj_t ** pClass, int nSize ) 
+{
+    assert( p->pId2Class[pRepr->Id] == NULL );
+    assert( pClass[0] == pRepr );
+    p->pId2Class[pRepr->Id] = pClass; 
+    assert( p->pClassSizes[pRepr->Id] == 0 );
+    assert( nSize > 1 );
+    p->pClassSizes[pRepr->Id] = nSize;
+    p->nClasses++;
+    p->nLits += nSize - 1;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Removes one equivalence class.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+static inline Aig_Obj_t ** Ssw_ObjRemoveClass( Ssw_Cla_t * p, Aig_Obj_t * pRepr ) 
+{
+    Aig_Obj_t ** pClass = p->pId2Class[pRepr->Id];
+    int nSize;
+    assert( pClass != NULL );
+    p->pId2Class[pRepr->Id] = NULL; 
+    nSize = p->pClassSizes[pRepr->Id];
+    assert( nSize > 1 );
+    p->nClasses--;
+    p->nLits -= nSize - 1;
+    p->pClassSizes[pRepr->Id] = 0;
+    return pClass;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Starts representation of equivalence classes.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Ssw_Cla_t * Ssw_ClassesStart( Aig_Man_t * pAig )
+{
+    Ssw_Cla_t * p;
+    p = ALLOC( Ssw_Cla_t, 1 );
+    memset( p, 0, sizeof(Ssw_Cla_t) );
+    p->pAig         = pAig;
+    p->pId2Class    = CALLOC( Aig_Obj_t **, Aig_ManObjNumMax(pAig) );
+    p->pClassSizes  = CALLOC( int, Aig_ManObjNumMax(pAig) );
+    p->vClassOld    = Vec_PtrAlloc( 100 );
+    p->vClassNew    = Vec_PtrAlloc( 100 );
+    p->vRefined     = Vec_PtrAlloc( 1000 );
+    assert( pAig->pReprs == NULL );
+    Aig_ManReprStart( pAig, Aig_ManObjNumMax(pAig) );
+    return p;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Starts representation of equivalence classes.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ssw_ClassesSetData( Ssw_Cla_t * p, void * pManData, 
+    unsigned (*pFuncNodeHash)(void *,Aig_Obj_t *),               // returns hash key of the node
+    int (*pFuncNodeIsConst)(void *,Aig_Obj_t *),                 // returns 1 if the node is a constant
+    int (*pFuncNodesAreEqual)(void *,Aig_Obj_t *, Aig_Obj_t *) ) // returns 1 if nodes are equal up to a complement
+{
+    p->pManData           = pManData;
+    p->pFuncNodeHash      = pFuncNodeHash;
+    p->pFuncNodeIsConst   = pFuncNodeIsConst;
+    p->pFuncNodesAreEqual = pFuncNodesAreEqual;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Stop representation of equivalence classes.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ssw_ClassesStop( Ssw_Cla_t * p )
+{
+    if ( p->vClassNew )    Vec_PtrFree( p->vClassNew );
+    if ( p->vClassOld )    Vec_PtrFree( p->vClassOld );
+    Vec_PtrFree( p->vRefined );
+    FREE( p->pId2Class );
+    FREE( p->pClassSizes );
+    FREE( p->pMemClasses );
+    free( p );
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Stop representation of equivalence classes.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Aig_Man_t * Ssw_ClassesReadAig( Ssw_Cla_t * p )
+{
+    return p->pAig;
+}
+
+/**Function*************************************************************
+
+  Synopsis    []
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Vec_Ptr_t * Ssw_ClassesGetRefined( Ssw_Cla_t * p )
+{
+    return p->vRefined;
+}
+
+/**Function*************************************************************
+
+  Synopsis    []
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ssw_ClassesClearRefined( Ssw_Cla_t * p )
+{
+    Vec_PtrClear( p->vRefined );
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Stop representation of equivalence classes.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Ssw_ClassesCand1Num( Ssw_Cla_t * p )
+{
+    return p->nCands1;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Stop representation of equivalence classes.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Ssw_ClassesClassNum( Ssw_Cla_t * p )
+{
+    return p->nClasses;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Stop representation of equivalence classes.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Ssw_ClassesLitNum( Ssw_Cla_t * p )
+{
+    return p->nLits;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Stop representation of equivalence classes.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Aig_Obj_t ** Ssw_ClassesReadClass( Ssw_Cla_t * p, Aig_Obj_t * pRepr, int * pnSize )
+{
+    if ( p->pId2Class[pRepr->Id] == NULL )
+        return NULL;
+    assert( p->pId2Class[pRepr->Id] != NULL );
+    assert( p->pClassSizes[pRepr->Id] > 1 );
+    *pnSize = p->pClassSizes[pRepr->Id];
+    return p->pId2Class[pRepr->Id];
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Stop representation of equivalence classes.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ssw_ClassesCollectClass( Ssw_Cla_t * p, Aig_Obj_t * pRepr, Vec_Ptr_t * vClass )
+{
+    int i;
+    Vec_PtrClear( vClass );
+    if ( p->pId2Class[pRepr->Id] == NULL )
+        return;
+    assert( p->pClassSizes[pRepr->Id] > 1 );
+    for ( i = 1; i < p->pClassSizes[pRepr->Id]; i++ )
+        Vec_PtrPush( vClass, p->pId2Class[pRepr->Id][i] );
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Checks candidate equivalence classes.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ssw_ClassesCheck( Ssw_Cla_t * p )
+{
+    Aig_Obj_t * pObj, * pPrev, ** ppClass;
+    int i, k, nLits, nClasses, nCands1;
+    nClasses = nLits = 0;
+    Ssw_ManForEachClass( p, ppClass, k )
+    {
+        pPrev = NULL;
+        assert( p->pClassSizes[ppClass[0]->Id] >= 2 );
+        Ssw_ClassForEachNode( p, ppClass[0], pObj, i )
+        {
+            if ( i == 0 )
+                assert( Aig_ObjRepr(p->pAig, pObj) == NULL );
+            else
+            {
+                assert( Aig_ObjRepr(p->pAig, pObj) == ppClass[0] );
+                assert( pPrev->Id < pObj->Id );
+                nLits++;
+            }
+            pPrev = pObj;
+        }
+        nClasses++;
+    }
+    nCands1 = 0;
+    Aig_ManForEachObj( p->pAig, pObj, i )
+        nCands1 += Ssw_ObjIsConst1Cand( p->pAig, pObj );
+    assert( p->nLits == nLits );
+    assert( p->nCands1 == nCands1 );
+    assert( p->nClasses == nClasses );
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Prints simulation classes.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ssw_ClassesPrintOne( Ssw_Cla_t * p, Aig_Obj_t * pRepr )
+{
+    Aig_Obj_t * pObj;
+    int i;
+    printf( "{ " );
+    Ssw_ClassForEachNode( p, pRepr, pObj, i )
+        printf( "%d(%d,%d) ", pObj->Id, pObj->Level, Aig_SupportSize(p->pAig,pObj) );
+    printf( "}\n" );
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Prints simulation classes.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ssw_ClassesPrint( Ssw_Cla_t * p, int fVeryVerbose )
+{
+    Aig_Obj_t ** ppClass;
+    Aig_Obj_t * pObj;
+    int i;
+    printf( "Equivalence classes: Const1 = %5d. Class = %5d. Lit = %5d.\n", 
+        p->nCands1, p->nClasses, p->nCands1+p->nLits );
+    if ( !fVeryVerbose )
+        return;
+    printf( "Constants { " );
+    Aig_ManForEachObj( p->pAig, pObj, i )
+        if ( Ssw_ObjIsConst1Cand( p->pAig, pObj ) )
+            printf( "%d(%d,%d) ", pObj->Id, pObj->Level, Aig_SupportSize(p->pAig,pObj) );
+    printf( "}\n" );
+    Ssw_ManForEachClass( p, ppClass, i )
+    {
+        printf( "%3d (%3d) : ", i, p->pClassSizes[i] );
+        Ssw_ClassesPrintOne( p, ppClass[0] );
+    }
+    printf( "\n" );
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Prints simulation classes.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ssw_ClassesRemoveNode( Ssw_Cla_t * p, Aig_Obj_t * pObj )
+{
+    Aig_Obj_t * pRepr, * pTemp;
+    assert( p->pClassSizes[pObj->Id] == 0 );
+    assert( p->pId2Class[pObj->Id] == NULL );
+    pRepr = Aig_ObjRepr( p->pAig, pObj );
+    assert( pRepr != NULL );
+    Vec_PtrPush( p->vRefined, pObj );
+    if ( Ssw_ObjIsConst1Cand( p->pAig, pObj ) )
+    {
+        assert( p->pClassSizes[pRepr->Id] == 0 );
+        assert( p->pId2Class[pRepr->Id] == NULL );
+        Aig_ObjSetRepr( p->pAig, pObj, NULL );
+        p->nCands1--;
+        return;
+    }
+    Vec_PtrPush( p->vRefined, pRepr );
+    Aig_ObjSetRepr( p->pAig, pObj, NULL );
+    assert( p->pId2Class[pRepr->Id][0] == pRepr );
+    assert( p->pClassSizes[pRepr->Id] >= 2 );
+    if ( p->pClassSizes[pRepr->Id] == 2 )
+    {
+        p->pId2Class[pRepr->Id] = NULL;
+        p->nClasses--;
+        p->pClassSizes[pRepr->Id] = 0;
+        p->nLits--;
+    }
+    else
+    {
+        int i, k = 0;
+        // remove the entry from the class
+        Ssw_ClassForEachNode( p, pRepr, pTemp, i )
+            if ( pTemp != pObj )
+                p->pId2Class[pRepr->Id][k++] = pTemp;
+        assert( k + 1 == p->pClassSizes[pRepr->Id] );
+        // reduce the class
+        p->pClassSizes[pRepr->Id]--;
+        p->nLits--;
+    }
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Creates initial simulation classes.]
+
+  Description [Assumes that simulation info is assigned.]
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Ssw_Cla_t * Ssw_ClassesPrepare( Aig_Man_t * pAig, int fLatchCorr, int nMaxLevs, int fVerbose )
+{
+    Ssw_Cla_t * p;
+    Ssw_Sml_t * pSml;
+    Aig_Obj_t ** ppTable, ** ppNexts, ** ppClassNew;
+    Aig_Obj_t * pObj, * pTemp, * pRepr;
+    int i, k, nTableSize, nNodes, iEntry, nEntries, nEntries2;
+    int clk;
+
+    // start the classes
+    p = Ssw_ClassesStart( pAig );
+
+    // perform sequential simulation
+clk = clock();
+    pSml = Ssw_SmlSimulateSeq( pAig, 0, 32, 4 );
+if ( fVerbose )
+{
+PRT( "Simulation of 32 frames with 4 words", clock() - clk );
+}
+
+    // set comparison procedures
+clk = clock();
+    Ssw_ClassesSetData( p, pSml, Ssw_SmlObjHashWord, Ssw_SmlObjIsConstWord, Ssw_SmlObjsAreEqualWord );
+
+    // allocate the hash table hashing simulation info into nodes
+    nTableSize = Aig_PrimeCudd( Aig_ManObjNumMax(p->pAig)/4 );
+    ppTable = CALLOC( Aig_Obj_t *, nTableSize ); 
+    ppNexts = CALLOC( Aig_Obj_t *, Aig_ManObjNumMax(p->pAig) ); 
+
+    // add all the nodes to the hash table
+    nEntries = 0;
+    Aig_ManForEachObj( p->pAig, pObj, i )
+    {
+        if ( fLatchCorr )
+        {
+            if ( !Saig_ObjIsLo(p->pAig, pObj) )
+                continue;
+        }
+        else
+        {
+            if ( !Aig_ObjIsNode(pObj) && !Aig_ObjIsPi(pObj) )
+                continue;
+            // skip the node with more that the given number of levels
+            if ( nMaxLevs && (int)pObj->Level > nMaxLevs )
+                continue;
+        }
+        // check if the node belongs to the class of constant 1
+        if ( p->pFuncNodeIsConst( p->pManData, pObj ) )
+        {
+            Ssw_ObjSetConst1Cand( p->pAig, pObj );
+            p->nCands1++;
+            continue;
+        }
+        // hash the node by its simulation info
+        iEntry = p->pFuncNodeHash( p->pManData, pObj ) % nTableSize;
+        // add the node to the class
+        if ( ppTable[iEntry] == NULL )
+            ppTable[iEntry] = pObj;
+        else
+        {
+            // set the representative of this node
+            pRepr = ppTable[iEntry];
+            Aig_ObjSetRepr( p->pAig, pObj, pRepr );
+            // add node to the table
+            if ( Ssw_ObjNext( ppNexts, pRepr ) == NULL )
+            { // this will be the second entry
+                p->pClassSizes[pRepr->Id]++;
+                nEntries++;
+            }
+            // add the entry to the list
+            Ssw_ObjSetNext( ppNexts, pObj, Ssw_ObjNext( ppNexts, pRepr ) );
+            Ssw_ObjSetNext( ppNexts, pRepr, pObj );
+            p->pClassSizes[pRepr->Id]++;
+            nEntries++;
+        }
+    }
+
+    // allocate room for classes
+    p->pMemClasses = ALLOC( Aig_Obj_t *, nEntries + p->nCands1 );
+    p->pMemClassesFree = p->pMemClasses + nEntries;
+ 
+    // copy the entries into storage in the topological order
+    nEntries2 = 0;
+    Aig_ManForEachObj( p->pAig, pObj, i )
+    {
+        if ( !Aig_ObjIsNode(pObj) && !Aig_ObjIsPi(pObj) )
+            continue;
+        nNodes = p->pClassSizes[pObj->Id];
+        // skip the nodes that are not representatives of non-trivial classes
+        if ( nNodes == 0 )
+            continue;
+        assert( nNodes > 1 );
+        // add the nodes to the class in the topological order
+        ppClassNew = p->pMemClasses + nEntries2;
+        ppClassNew[0] = pObj;
+        for ( pTemp = Ssw_ObjNext(ppNexts, pObj), k = 1; pTemp; 
+              pTemp = Ssw_ObjNext(ppNexts, pTemp), k++ )
+        {
+            ppClassNew[nNodes-k] = pTemp;
+        }
+        // add the class of nodes
+        p->pClassSizes[pObj->Id] = 0;
+        Ssw_ObjAddClass( p, pObj, ppClassNew, nNodes );
+        // increment the number of entries
+        nEntries2 += nNodes;
+    }
+    assert( nEntries == nEntries2 );
+    free( ppTable );
+    free( ppNexts );
+
+    // now it is time to refine the classes
+    Ssw_ClassesRefine( p, 1 );
+    Ssw_ClassesCheck( p );
+    Ssw_SmlStop( pSml );
+//    Ssw_ClassesPrint( p, 0 );
+if ( fVerbose )
+{
+PRT( "Collecting candidate equival classes", clock() - clk );
+}
+    return p;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Creates initial simulation classes.]
+
+  Description [Assumes that simulation info is assigned.]
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Ssw_Cla_t * Ssw_ClassesPrepareSimple( Aig_Man_t * pAig, int fLatchCorr, int nMaxLevs )
+{
+    Ssw_Cla_t * p;
+    Aig_Obj_t * pObj;
+    int i;
+    // start the classes
+    p = Ssw_ClassesStart( pAig );
+    // go through the nodes
+    p->nCands1 = 0;
+    Aig_ManForEachObj( pAig, pObj, i )
+    {
+        if ( fLatchCorr )
+        {
+            if ( !Saig_ObjIsLo(pAig, pObj) )
+                continue;
+        }
+        else
+        {
+            if ( !Aig_ObjIsNode(pObj) && !Saig_ObjIsLo(pAig, pObj) )
+                continue;
+            // skip the node with more that the given number of levels
+            if ( nMaxLevs && (int)pObj->Level > nMaxLevs )
+                continue;
+        }
+        Ssw_ObjSetConst1Cand( pAig, pObj );
+        p->nCands1++;
+    }
+    // allocate room for classes
+    p->pMemClassesFree = p->pMemClasses = ALLOC( Aig_Obj_t *, p->nCands1 );
+//    Ssw_ClassesPrint( p, 0 );
+    return p;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Creates initial simulation classes.]
+
+  Description [Assumes that simulation info is assigned.]
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Ssw_Cla_t * Ssw_ClassesPrepareTargets( Aig_Man_t * pAig )
+{
+    Ssw_Cla_t * p;
+    Aig_Obj_t * pObj;
+    int i;
+    // start the classes
+    p = Ssw_ClassesStart( pAig );
+    // go through the nodes
+    p->nCands1 = 0;
+    Saig_ManForEachPo( pAig, pObj, i )
+    {
+        Ssw_ObjSetConst1Cand( pAig, Aig_ObjFanin0(pObj) );
+        p->nCands1++;
+    }
+    // allocate room for classes
+    p->pMemClassesFree = p->pMemClasses = ALLOC( Aig_Obj_t *, p->nCands1 );
+//    Ssw_ClassesPrint( p, 0 );
+    return p;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Creates classes from the temporary representation.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Ssw_Cla_t * Ssw_ClassesPreparePairs( Aig_Man_t * pAig, Vec_Int_t ** pvClasses )
+{
+    Ssw_Cla_t * p;
+    Aig_Obj_t ** ppClassNew;
+    Aig_Obj_t * pObj, * pRepr, * pPrev;
+    int i, k, nTotalObjs, nEntries, Entry;
+    // start the classes
+    p = Ssw_ClassesStart( pAig );
+    // count the number of entries in the classes
+    nTotalObjs = 0;
+    for ( i = 0; i < Aig_ManObjNumMax(pAig); i++ )
+        nTotalObjs += pvClasses[i] ? Vec_IntSize(pvClasses[i]) : 0; 
+    // allocate memory for classes
+    p->pMemClasses = ALLOC( Aig_Obj_t *, nTotalObjs );
+    // create constant-1 class
+    if ( pvClasses[0] )
+    Vec_IntForEachEntry( pvClasses[0], Entry, i )
+    {
+        assert( (i == 0) == (Entry == 0) );
+        if ( i == 0 )
+            continue;
+        pObj = Aig_ManObj( pAig, Entry );
+        Ssw_ObjSetConst1Cand( pAig, pObj );
+        p->nCands1++;
+    }
+    // create classes
+    nEntries = 0;
+    for ( i = 1; i < Aig_ManObjNumMax(pAig); i++ )
+    {
+        if ( pvClasses[i] == NULL )
+            continue;
+        // get room for storing the class
+        ppClassNew = p->pMemClasses + nEntries;
+        nEntries  += Vec_IntSize( pvClasses[i] );
+        // store the nodes of the class
+        pPrev = pRepr = Aig_ManObj( pAig, Vec_IntEntry(pvClasses[i],0) );
+        ppClassNew[0] = pRepr;
+        Vec_IntForEachEntryStart( pvClasses[i], Entry, k, 1 )
+        {
+            pObj = Aig_ManObj( pAig, Entry );
+            assert( pPrev->Id < pObj->Id );
+            pPrev = pObj;
+            ppClassNew[k] = pObj;
+            Aig_ObjSetRepr( pAig, pObj, pRepr );
+        }
+        // create new class
+        Ssw_ObjAddClass( p, pRepr, ppClassNew, Vec_IntSize(pvClasses[i]) );
+    }
+    // prepare room for new classes
+    p->pMemClassesFree = p->pMemClasses + nEntries;
+    Ssw_ClassesCheck( p );
+//    Ssw_ClassesPrint( p, 0 );
+    return p;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Iteratively refines the classes after simulation.]
+
+  Description [Returns the number of refinements performed.]
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Ssw_ClassesRefineOneClass( Ssw_Cla_t * p, Aig_Obj_t * pReprOld, int fRecursive )
+{
+    Aig_Obj_t ** pClassOld, ** pClassNew;
+    Aig_Obj_t * pObj, * pReprNew;
+    int i;
+
+    // split the class
+    Vec_PtrClear( p->vClassOld );
+    Vec_PtrClear( p->vClassNew );
+    Ssw_ClassForEachNode( p, pReprOld, pObj, i )
+        if ( p->pFuncNodesAreEqual(p->pManData, pReprOld, pObj) )
+            Vec_PtrPush( p->vClassOld, pObj );
+        else
+            Vec_PtrPush( p->vClassNew, pObj );
+    // check if splitting happened
+    if ( Vec_PtrSize(p->vClassNew) == 0 )
+        return 0;
+    // remember that this class is refined
+    Ssw_ClassForEachNode( p, pReprOld, pObj, i )
+        Vec_PtrPush( p->vRefined, pObj );
+
+    // get the new representative
+    pReprNew = Vec_PtrEntry( p->vClassNew, 0 );
+    assert( Vec_PtrSize(p->vClassOld) > 0 );
+    assert( Vec_PtrSize(p->vClassNew) > 0 );
+
+    // create old class
+    pClassOld = Ssw_ObjRemoveClass( p, pReprOld );
+    Vec_PtrForEachEntry( p->vClassOld, pObj, i )
+    {
+        pClassOld[i] = pObj;
+        Aig_ObjSetRepr( p->pAig, pObj, i? pReprOld : NULL );
+    }
+    // create new class
+    pClassNew = pClassOld + i;
+    Vec_PtrForEachEntry( p->vClassNew, pObj, i )
+    {
+        pClassNew[i] = pObj;
+        Aig_ObjSetRepr( p->pAig, pObj, i? pReprNew : NULL );
+    }
+
+    // put classes back
+    if ( Vec_PtrSize(p->vClassOld) > 1 )
+        Ssw_ObjAddClass( p, pReprOld, pClassOld, Vec_PtrSize(p->vClassOld) );
+    if ( Vec_PtrSize(p->vClassNew) > 1 )
+        Ssw_ObjAddClass( p, pReprNew, pClassNew, Vec_PtrSize(p->vClassNew) );
+
+    // check if the class should be recursively refined
+    if ( fRecursive && Vec_PtrSize(p->vClassNew) > 1 )
+        return 1 + Ssw_ClassesRefineOneClass( p, pReprNew, 1 );
+    return 1;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Refines the classes after simulation.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Ssw_ClassesRefine( Ssw_Cla_t * p, int fRecursive )
+{
+    Aig_Obj_t ** ppClass;
+    int i, nRefis = 0;
+    Ssw_ManForEachClass( p, ppClass, i )
+        nRefis += Ssw_ClassesRefineOneClass( p, ppClass[0], fRecursive );
+    return nRefis;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Refine the group of constant 1 nodes.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Ssw_ClassesRefineConst1Group( Ssw_Cla_t * p, Vec_Ptr_t * vRoots, int fRecursive )
+{
+    Aig_Obj_t * pObj, * pReprNew, ** ppClassNew;
+    int i;
+    if ( Vec_PtrSize(vRoots) == 0 )
+        return 0;
+    // collect the nodes to be refined
+    Vec_PtrClear( p->vClassNew );
+    Vec_PtrForEachEntry( vRoots, pObj, i )
+        if ( !p->pFuncNodeIsConst( p->pManData, pObj ) )
+            Vec_PtrPush( p->vClassNew, pObj );
+    // check if there is a new class
+    if ( Vec_PtrSize(p->vClassNew) == 0 )
+        return 0;
+    p->nCands1 -= Vec_PtrSize(p->vClassNew);
+    pReprNew = Vec_PtrEntry( p->vClassNew, 0 );
+    Aig_ObjSetRepr( p->pAig, pReprNew, NULL );
+    if ( Vec_PtrSize(p->vClassNew) == 1 )
+        return 1;
+    // create a new class composed of these nodes
+    ppClassNew = p->pMemClassesFree;
+    p->pMemClassesFree += Vec_PtrSize(p->vClassNew);
+    Vec_PtrForEachEntry( p->vClassNew, pObj, i )
+    {
+        ppClassNew[i] = pObj;
+        Aig_ObjSetRepr( p->pAig, pObj, i? pReprNew : NULL );
+    }
+    Ssw_ObjAddClass( p, pReprNew, ppClassNew, Vec_PtrSize(p->vClassNew) );
+    // refine them recursively
+    if ( fRecursive )
+        return 1 + Ssw_ClassesRefineOneClass( p, pReprNew, 1 );
+    return 1;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Refine the group of constant 1 nodes.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Ssw_ClassesRefineConst1( Ssw_Cla_t * p, int fRecursive )
+{
+    Aig_Obj_t * pObj, * pReprNew, ** ppClassNew;
+    int i;
+    // collect the nodes to be refined
+    Vec_PtrClear( p->vClassNew );
+    for ( i = 0; i < Vec_PtrSize(p->pAig->vObjs); i++ )
+        if ( p->pAig->pReprs[i] == Aig_ManConst1(p->pAig) )
+        {
+            pObj = Aig_ManObj( p->pAig, i );
+            if ( !p->pFuncNodeIsConst( p->pManData, pObj ) )
+            {
+                Vec_PtrPush( p->vClassNew, pObj );
+                Vec_PtrPush( p->vRefined, pObj );
+            }
+        }
+    // check if there is a new class
+    if ( Vec_PtrSize(p->vClassNew) == 0 )
+        return 0;
+    p->nCands1 -= Vec_PtrSize(p->vClassNew);
+    pReprNew = Vec_PtrEntry( p->vClassNew, 0 );
+    Aig_ObjSetRepr( p->pAig, pReprNew, NULL );
+    if ( Vec_PtrSize(p->vClassNew) == 1 )
+        return 1;
+    // create a new class composed of these nodes
+    ppClassNew = p->pMemClassesFree;
+    p->pMemClassesFree += Vec_PtrSize(p->vClassNew);
+    Vec_PtrForEachEntry( p->vClassNew, pObj, i )
+    {
+        ppClassNew[i] = pObj;
+        Aig_ObjSetRepr( p->pAig, pObj, i? pReprNew : NULL );
+    }
+    Ssw_ObjAddClass( p, pReprNew, ppClassNew, Vec_PtrSize(p->vClassNew) );
+    // refine them recursively
+    if ( fRecursive )
+        return 1 + Ssw_ClassesRefineOneClass( p, pReprNew, 1 );
+    return 1;
+}
+
+
+////////////////////////////////////////////////////////////////////////
+///                       END OF FILE                                ///
+////////////////////////////////////////////////////////////////////////
+
+
diff --git a/src/aig/ssw_old/sswCnf.c b/src/aig/ssw_old/sswCnf.c
new file mode 100644
index 00000000..e4b8f9f6
--- /dev/null
+++ b/src/aig/ssw_old/sswCnf.c
@@ -0,0 +1,335 @@
+/**CFile****************************************************************
+
+  FileName    [sswCnf.c]
+
+  SystemName  [ABC: Logic synthesis and verification system.]
+
+  PackageName [Inductive prover with constraints.]
+
+  Synopsis    [Computation of CNF.]
+
+  Author      [Alan Mishchenko]
+  
+  Affiliation [UC Berkeley]
+
+  Date        [Ver. 1.0. Started - September 1, 2008.]
+
+  Revision    [$Id: sswCnf.c,v 1.00 2008/09/01 00:00:00 alanmi Exp $]
+
+***********************************************************************/
+
+#include "sswInt.h"
+
+////////////////////////////////////////////////////////////////////////
+///                        DECLARATIONS                              ///
+////////////////////////////////////////////////////////////////////////
+
+////////////////////////////////////////////////////////////////////////
+///                     FUNCTION DEFINITIONS                         ///
+////////////////////////////////////////////////////////////////////////
+
+/**Function*************************************************************
+
+  Synopsis    [Addes clauses to the solver.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ssw_AddClausesMux( Ssw_Man_t * p, Aig_Obj_t * pNode )
+{
+    Aig_Obj_t * pNodeI, * pNodeT, * pNodeE;
+    int pLits[4], RetValue, VarF, VarI, VarT, VarE, fCompT, fCompE;
+
+    assert( !Aig_IsComplement( pNode ) );
+    assert( Aig_ObjIsMuxType( pNode ) );
+    // get nodes (I = if, T = then, E = else)
+    pNodeI = Aig_ObjRecognizeMux( pNode, &pNodeT, &pNodeE );
+    // get the variable numbers
+    VarF = Ssw_ObjSatNum(p,pNode);
+    VarI = Ssw_ObjSatNum(p,pNodeI);
+    VarT = Ssw_ObjSatNum(p,Aig_Regular(pNodeT));
+    VarE = Ssw_ObjSatNum(p,Aig_Regular(pNodeE));
+    // get the complementation flags
+    fCompT = Aig_IsComplement(pNodeT);
+    fCompE = Aig_IsComplement(pNodeE);
+
+    // f = ITE(i, t, e)
+
+    // i' + t' + f
+    // i' + t  + f'
+    // i  + e' + f
+    // i  + e  + f'
+
+    // create four clauses
+    pLits[0] = toLitCond(VarI, 1);
+    pLits[1] = toLitCond(VarT, 1^fCompT);
+    pLits[2] = toLitCond(VarF, 0);
+    if ( p->pPars->fPolarFlip )
+    {
+        if ( pNodeI->fPhase )               pLits[0] = lit_neg( pLits[0] );
+        if ( Aig_Regular(pNodeT)->fPhase )  pLits[1] = lit_neg( pLits[1] );
+        if ( pNode->fPhase )                pLits[2] = lit_neg( pLits[2] );
+    }
+    RetValue = sat_solver_addclause( p->pSat, pLits, pLits + 3 );
+    assert( RetValue );
+    pLits[0] = toLitCond(VarI, 1);
+    pLits[1] = toLitCond(VarT, 0^fCompT);
+    pLits[2] = toLitCond(VarF, 1);
+    if ( p->pPars->fPolarFlip )
+    {
+        if ( pNodeI->fPhase )               pLits[0] = lit_neg( pLits[0] );
+        if ( Aig_Regular(pNodeT)->fPhase )  pLits[1] = lit_neg( pLits[1] );
+        if ( pNode->fPhase )                pLits[2] = lit_neg( pLits[2] );
+    }
+    RetValue = sat_solver_addclause( p->pSat, pLits, pLits + 3 );
+    assert( RetValue );
+    pLits[0] = toLitCond(VarI, 0);
+    pLits[1] = toLitCond(VarE, 1^fCompE);
+    pLits[2] = toLitCond(VarF, 0);
+    if ( p->pPars->fPolarFlip )
+    {
+        if ( pNodeI->fPhase )               pLits[0] = lit_neg( pLits[0] );
+        if ( Aig_Regular(pNodeE)->fPhase )  pLits[1] = lit_neg( pLits[1] );
+        if ( pNode->fPhase )                pLits[2] = lit_neg( pLits[2] );
+    }
+    RetValue = sat_solver_addclause( p->pSat, pLits, pLits + 3 );
+    assert( RetValue );
+    pLits[0] = toLitCond(VarI, 0);
+    pLits[1] = toLitCond(VarE, 0^fCompE);
+    pLits[2] = toLitCond(VarF, 1);
+    if ( p->pPars->fPolarFlip )
+    {
+        if ( pNodeI->fPhase )               pLits[0] = lit_neg( pLits[0] );
+        if ( Aig_Regular(pNodeE)->fPhase )  pLits[1] = lit_neg( pLits[1] );
+        if ( pNode->fPhase )                pLits[2] = lit_neg( pLits[2] );
+    }
+    RetValue = sat_solver_addclause( p->pSat, pLits, pLits + 3 );
+    assert( RetValue );
+
+    // two additional clauses
+    // t' & e' -> f'
+    // t  & e  -> f 
+
+    // t  + e   + f'
+    // t' + e'  + f 
+
+    if ( VarT == VarE )
+    {
+//        assert( fCompT == !fCompE );
+        return;
+    }
+
+    pLits[0] = toLitCond(VarT, 0^fCompT);
+    pLits[1] = toLitCond(VarE, 0^fCompE);
+    pLits[2] = toLitCond(VarF, 1);
+    if ( p->pPars->fPolarFlip )
+    {
+        if ( Aig_Regular(pNodeT)->fPhase )  pLits[0] = lit_neg( pLits[0] );
+        if ( Aig_Regular(pNodeE)->fPhase )  pLits[1] = lit_neg( pLits[1] );
+        if ( pNode->fPhase )                pLits[2] = lit_neg( pLits[2] );
+    }
+    RetValue = sat_solver_addclause( p->pSat, pLits, pLits + 3 );
+    assert( RetValue );
+    pLits[0] = toLitCond(VarT, 1^fCompT);
+    pLits[1] = toLitCond(VarE, 1^fCompE);
+    pLits[2] = toLitCond(VarF, 0);
+    if ( p->pPars->fPolarFlip )
+    {
+        if ( Aig_Regular(pNodeT)->fPhase )  pLits[0] = lit_neg( pLits[0] );
+        if ( Aig_Regular(pNodeE)->fPhase )  pLits[1] = lit_neg( pLits[1] );
+        if ( pNode->fPhase )                pLits[2] = lit_neg( pLits[2] );
+    }
+    RetValue = sat_solver_addclause( p->pSat, pLits, pLits + 3 );
+    assert( RetValue );
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Addes clauses to the solver.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ssw_AddClausesSuper( Ssw_Man_t * p, Aig_Obj_t * pNode, Vec_Ptr_t * vSuper )
+{
+    Aig_Obj_t * pFanin;
+    int * pLits, nLits, RetValue, i;
+    assert( !Aig_IsComplement(pNode) );
+    assert( Aig_ObjIsNode( pNode ) );
+    // create storage for literals
+    nLits = Vec_PtrSize(vSuper) + 1;
+    pLits = ALLOC( int, nLits );
+    // suppose AND-gate is A & B = C
+    // add !A => !C   or   A + !C
+    Vec_PtrForEachEntry( vSuper, pFanin, i )
+    {
+        pLits[0] = toLitCond(Ssw_ObjSatNum(p,Aig_Regular(pFanin)), Aig_IsComplement(pFanin));
+        pLits[1] = toLitCond(Ssw_ObjSatNum(p,pNode), 1);
+        if ( p->pPars->fPolarFlip )
+        {
+            if ( Aig_Regular(pFanin)->fPhase )  pLits[0] = lit_neg( pLits[0] );
+            if ( pNode->fPhase )                pLits[1] = lit_neg( pLits[1] );
+        }
+        RetValue = sat_solver_addclause( p->pSat, pLits, pLits + 2 );
+        assert( RetValue );
+    }
+    // add A & B => C   or   !A + !B + C
+    Vec_PtrForEachEntry( vSuper, pFanin, i )
+    {
+        pLits[i] = toLitCond(Ssw_ObjSatNum(p,Aig_Regular(pFanin)), !Aig_IsComplement(pFanin));
+        if ( p->pPars->fPolarFlip )
+        {
+            if ( Aig_Regular(pFanin)->fPhase )  pLits[i] = lit_neg( pLits[i] );
+        }
+    }
+    pLits[nLits-1] = toLitCond(Ssw_ObjSatNum(p,pNode), 0);
+    if ( p->pPars->fPolarFlip )
+    {
+        if ( pNode->fPhase )  pLits[nLits-1] = lit_neg( pLits[nLits-1] );
+    }
+    RetValue = sat_solver_addclause( p->pSat, pLits, pLits + nLits );
+    assert( RetValue );
+    free( pLits );
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Collects the supergate.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ssw_CollectSuper_rec( Aig_Obj_t * pObj, Vec_Ptr_t * vSuper, int fFirst, int fUseMuxes )
+{
+    // if the new node is complemented or a PI, another gate begins
+    if ( Aig_IsComplement(pObj) || Aig_ObjIsPi(pObj) || 
+         (!fFirst && Aig_ObjRefs(pObj) > 1) || 
+         (fUseMuxes && Aig_ObjIsMuxType(pObj)) )
+    {
+        Vec_PtrPushUnique( vSuper, pObj );
+        return;
+    }
+    // go through the branches
+    Ssw_CollectSuper_rec( Aig_ObjChild0(pObj), vSuper, 0, fUseMuxes );
+    Ssw_CollectSuper_rec( Aig_ObjChild1(pObj), vSuper, 0, fUseMuxes );
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Collects the supergate.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ssw_CollectSuper( Aig_Obj_t * pObj, int fUseMuxes, Vec_Ptr_t * vSuper )
+{
+    assert( !Aig_IsComplement(pObj) );
+    assert( !Aig_ObjIsPi(pObj) );
+    Vec_PtrClear( vSuper );
+    Ssw_CollectSuper_rec( pObj, vSuper, 1, fUseMuxes );
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Updates the solver clause database.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ssw_ObjAddToFrontier( Ssw_Man_t * p, Aig_Obj_t * pObj, Vec_Ptr_t * vFrontier )
+{
+    assert( !Aig_IsComplement(pObj) );
+    if ( Ssw_ObjSatNum(p,pObj) )
+        return;
+    assert( Ssw_ObjSatNum(p,pObj) == 0 );
+    if ( Aig_ObjIsConst1(pObj) )
+        return;
+    if ( p->pPars->fLatchCorrOpt )
+    {
+        Vec_PtrPush( p->vUsedNodes, pObj );
+        if ( Aig_ObjIsPi(pObj) )
+            Vec_PtrPush( p->vUsedPis, pObj );
+    }
+    Ssw_ObjSetSatNum( p, pObj, p->nSatVars++ );
+    sat_solver_setnvars( p->pSat, 100 * (1 + p->nSatVars / 100) );
+    if ( Aig_ObjIsNode(pObj) )
+        Vec_PtrPush( vFrontier, pObj );
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Updates the solver clause database.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ssw_CnfNodeAddToSolver( Ssw_Man_t * p, Aig_Obj_t * pObj )
+{ 
+    Vec_Ptr_t * vFrontier;
+    Aig_Obj_t * pNode, * pFanin;
+    int i, k, fUseMuxes = 1;
+    // quit if CNF is ready
+    if ( Ssw_ObjSatNum(p,pObj) )
+        return;
+    // start the frontier
+    vFrontier = Vec_PtrAlloc( 100 );
+    Ssw_ObjAddToFrontier( p, pObj, vFrontier );
+    // explore nodes in the frontier
+    Vec_PtrForEachEntry( vFrontier, pNode, i )
+    {
+        // create the supergate
+        assert( Ssw_ObjSatNum(p,pNode) );
+        if ( fUseMuxes && Aig_ObjIsMuxType(pNode) )
+        {
+            Vec_PtrClear( p->vFanins );
+            Vec_PtrPushUnique( p->vFanins, Aig_ObjFanin0( Aig_ObjFanin0(pNode) ) );
+            Vec_PtrPushUnique( p->vFanins, Aig_ObjFanin0( Aig_ObjFanin1(pNode) ) );
+            Vec_PtrPushUnique( p->vFanins, Aig_ObjFanin1( Aig_ObjFanin0(pNode) ) );
+            Vec_PtrPushUnique( p->vFanins, Aig_ObjFanin1( Aig_ObjFanin1(pNode) ) );
+            Vec_PtrForEachEntry( p->vFanins, pFanin, k )
+                Ssw_ObjAddToFrontier( p, Aig_Regular(pFanin), vFrontier );
+            Ssw_AddClausesMux( p, pNode );
+        }
+        else
+        {
+            Ssw_CollectSuper( pNode, fUseMuxes, p->vFanins );
+            Vec_PtrForEachEntry( p->vFanins, pFanin, k )
+                Ssw_ObjAddToFrontier( p, Aig_Regular(pFanin), vFrontier );
+            Ssw_AddClausesSuper( p, pNode, p->vFanins );
+        }
+        assert( Vec_PtrSize(p->vFanins) > 1 );
+    }
+    Vec_PtrFree( vFrontier );
+}
+
+
+
+////////////////////////////////////////////////////////////////////////
+///                       END OF FILE                                ///
+////////////////////////////////////////////////////////////////////////
+
+
diff --git a/src/aig/ssw_old/sswCore.c b/src/aig/ssw_old/sswCore.c
new file mode 100644
index 00000000..5b33d96c
--- /dev/null
+++ b/src/aig/ssw_old/sswCore.c
@@ -0,0 +1,293 @@
+/**CFile****************************************************************
+
+  FileName    [sswCore.c]
+
+  SystemName  [ABC: Logic synthesis and verification system.]
+
+  PackageName [Inductive prover with constraints.]
+
+  Synopsis    [The core procedures.]
+
+  Author      [Alan Mishchenko]
+  
+  Affiliation [UC Berkeley]
+
+  Date        [Ver. 1.0. Started - September 1, 2008.]
+
+  Revision    [$Id: sswCore.c,v 1.00 2008/09/01 00:00:00 alanmi Exp $]
+
+***********************************************************************/
+
+#include "sswInt.h"
+
+////////////////////////////////////////////////////////////////////////
+///                        DECLARATIONS                              ///
+////////////////////////////////////////////////////////////////////////
+
+////////////////////////////////////////////////////////////////////////
+///                     FUNCTION DEFINITIONS                         ///
+////////////////////////////////////////////////////////////////////////
+
+/**Function*************************************************************
+
+  Synopsis    [This procedure sets default parameters.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ssw_ManSetDefaultParams( Ssw_Pars_t * p )
+{
+    memset( p, 0, sizeof(Ssw_Pars_t) );
+    p->nPartSize      =     0;  // size of the partition
+    p->nOverSize      =     0;  // size of the overlap between partitions
+    p->nFramesK       =     1;  // the induction depth
+    p->nFramesAddSim  =     0;  // additional frames to simulate
+    p->nConstrs       =     0;  // treat the last nConstrs POs as seq constraints
+    p->nBTLimit       =  1000;  // conflict limit at a node
+    p->nMinDomSize    =   100;  // min clock domain considered for optimization
+    p->fPolarFlip     =     0;  // uses polarity adjustment
+    p->fSkipCheck     =     0;  // do not run equivalence check for unaffected cones
+    p->fLatchCorr     =     0;  // performs register correspondence
+    p->fSemiFormal    =     0;  // enable semiformal filtering
+    p->fUniqueness    =     0;  // enable uniqueness constraints
+    p->fVerbose       =     0;  // verbose stats
+    // latch correspondence
+    p->fLatchCorrOpt  =     0;  // performs optimized register correspondence
+    p->nSatVarMax     =  1000;  // the max number of SAT variables
+    p->nRecycleCalls  =    50;  // calls to perform before recycling SAT solver
+    // return values
+    p->nIters         =     0;  // the number of iterations performed
+}
+
+/**Function*************************************************************
+
+  Synopsis    [This procedure sets default parameters.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ssw_ManSetDefaultParamsLcorr( Ssw_Pars_t * p )
+{
+    Ssw_ManSetDefaultParams( p );
+    p->fLatchCorrOpt = 1;
+    p->nBTLimit      = 10000;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Performs computation of signal correspondence with constraints.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Aig_Man_t * Ssw_SignalCorrespondenceRefine( Ssw_Man_t * p )
+{
+    int nSatProof, nSatCallsSat, nRecycles, nSatFailsReal;
+    Aig_Man_t * pAigNew;
+    int RetValue, nIter;
+    int clk, clkTotal = clock();
+    // get the starting stats
+    p->nLitsBeg  = Ssw_ClassesLitNum( p->ppClasses );
+    p->nNodesBeg = Aig_ManNodeNum(p->pAig);
+    p->nRegsBeg  = Aig_ManRegNum(p->pAig);
+    // refine classes using BMC
+    if ( p->pPars->fVerbose )
+    {
+        printf( "Before BMC: " );
+        Ssw_ClassesPrint( p->ppClasses, 0 );
+    }
+    if ( !p->pPars->fLatchCorr )
+    { 
+        Ssw_ManSweepBmc( p );
+        Ssw_ManCleanup( p );
+    }
+    if ( p->pPars->fVerbose )
+    {
+        printf( "After  BMC: " );
+        Ssw_ClassesPrint( p->ppClasses, 0 );
+    }
+    // apply semi-formal filtering
+    if ( p->pPars->fSemiFormal )
+    {
+        Aig_Man_t * pSRed;
+        Ssw_FilterUsingBmc( p, 0, 2000, p->pPars->fVerbose );
+//        Ssw_FilterUsingBmc( p, 1, 100000, p->pPars->fVerbose );
+        pSRed = Ssw_SpeculativeReduction( p );
+        Aig_ManDumpBlif( pSRed, "srm.blif", NULL, NULL );
+        Aig_ManStop( pSRed );
+    }
+    // refine classes using induction
+    nSatProof = nSatCallsSat = nRecycles = nSatFailsReal = 0;
+    for ( nIter = 0; ; nIter++ )
+    {
+clk = clock();
+        if ( p->pPars->fLatchCorrOpt )
+        {
+            RetValue = Ssw_ManSweepLatch( p );
+            if ( p->pPars->fVerbose )
+            {
+                printf( "%3d : Const = %6d. Cl = %6d. Pr = %5d. Cex = %5d. Rcl = %3d. F = %3d. ", 
+                    nIter, Ssw_ClassesCand1Num(p->ppClasses), Ssw_ClassesClassNum(p->ppClasses), 
+                    p->nSatProof-nSatProof, p->nSatCallsSat-nSatCallsSat, 
+                    p->nRecycles-nRecycles, p->nSatFailsReal-nSatFailsReal );
+                PRT( "T", clock() - clk );
+                nSatProof     = p->nSatProof;
+                nSatCallsSat  = p->nSatCallsSat;
+                nRecycles     = p->nRecycles;
+                nSatFailsReal = p->nSatFailsReal;
+            } 
+        }
+        else
+        {
+//            if ( nIter == 6 )
+//                p->pPars->fUniqueness = 0;
+
+            RetValue = Ssw_ManSweep( p );
+            if ( p->pPars->fVerbose )
+            {
+                printf( "%3d : Const = %6d. Cl = %6d. LR = %6d. NR = %6d. U = %3d. F = %2d. ", 
+                    nIter, Ssw_ClassesCand1Num(p->ppClasses), Ssw_ClassesClassNum(p->ppClasses), 
+                    p->nConstrReduced, Aig_ManNodeNum(p->pFrames), p->nUniques, p->nSatFailsReal );
+                if ( p->pPars->fSkipCheck )
+                    printf( "Use = %5d. Skip = %5d. ", 
+                        p->nRefUse, p->nRefSkip );
+                PRT( "T", clock() - clk );
+            } 
+        }
+        Ssw_ManCleanup( p );
+        if ( !RetValue )
+            break;
+/*
+        {
+            static int Flag = 0;
+            if ( Flag++ == 4 && nIter == 4 )
+            {
+                Aig_Man_t * pSRed;
+                pSRed = Ssw_SpeculativeReduction( p );
+                Aig_ManDumpBlif( pSRed, "srm.blif", NULL, NULL );
+                Aig_ManStop( pSRed );
+            }
+        }
+*/
+
+    } 
+    p->pPars->nIters = nIter + 1;
+p->timeTotal = clock() - clkTotal;
+    pAigNew = Aig_ManDupRepr( p->pAig, 0 );
+    Aig_ManSeqCleanup( pAigNew );
+    // get the final stats
+    p->nLitsEnd  = Ssw_ClassesLitNum( p->ppClasses );
+    p->nNodesEnd = Aig_ManNodeNum(pAigNew);
+    p->nRegsEnd  = Aig_ManRegNum(pAigNew);
+    return pAigNew;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Performs computation of signal correspondence with constraints.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Aig_Man_t * Ssw_SignalCorrespondence( Aig_Man_t * pAig, Ssw_Pars_t * pPars )
+{
+    Ssw_Pars_t Pars;
+    Aig_Man_t * pAigNew;
+    Ssw_Man_t * p;
+    assert( Aig_ManRegNum(pAig) > 0 );
+    // reset random numbers
+    Aig_ManRandom( 1 );
+    // if parameters are not given, create them
+    if ( pPars == NULL )
+        Ssw_ManSetDefaultParams( pPars = &Pars );
+    // consider the case of empty AIG
+    if ( Aig_ManNodeNum(pAig) == 0 )
+    {
+        pPars->nIters = 0;
+        // Ntl_ManFinalize() needs the following to satisfy an assertion
+        Aig_ManReprStart( pAig,Aig_ManObjNumMax(pAig) );
+        return Aig_ManDupOrdered(pAig);
+    }
+    // check and update parameters
+    if ( pPars->fLatchCorrOpt )
+    {
+        pPars->fLatchCorr = 1;
+        pPars->nFramesAddSim = 0;
+    }
+    else
+    {
+        assert( pPars->nFramesK > 0 );
+        if ( pPars->nFramesK > 1 )
+            pPars->fSkipCheck = 0;
+        // perform partitioning
+        if ( (pPars->nPartSize > 0 && pPars->nPartSize < Aig_ManRegNum(pAig))
+             || (pAig->vClockDoms && Vec_VecSize(pAig->vClockDoms) > 0)  )
+            return Ssw_SignalCorrespondencePart( pAig, pPars );
+    }
+    // start the induction manager
+    p = Ssw_ManCreate( pAig, pPars );
+    // compute candidate equivalence classes
+//    p->pPars->nConstrs = 1;
+    if ( p->pPars->nConstrs == 0 )
+    {
+        // perform one round of seq simulation and generate candidate equivalence classes
+        p->ppClasses = Ssw_ClassesPrepare( pAig, pPars->fLatchCorr, pPars->nMaxLevs, pPars->fVerbose );
+//        p->ppClasses = Ssw_ClassesPrepareTargets( pAig );
+//        p->pSml = Ssw_SmlStart( pAig, 0, p->nFrames + p->pPars->nFramesAddSim, 1 );
+        p->pSml = Ssw_SmlStart( pAig, 0, 1, 1 );
+        Ssw_ClassesSetData( p->ppClasses, p->pSml, Ssw_SmlObjHashWord, Ssw_SmlObjIsConstWord, Ssw_SmlObjsAreEqualWord );
+    }
+    else
+    {
+        // create trivial equivalence classes with all nodes being candidates for constant 1
+        p->ppClasses = Ssw_ClassesPrepareSimple( pAig, pPars->fLatchCorr, pPars->nMaxLevs );
+        Ssw_ClassesSetData( p->ppClasses, NULL, NULL, Ssw_SmlObjIsConstBit, Ssw_SmlObjsAreEqualBit );
+    }
+    // perform refinement of classes
+    pAigNew = Ssw_SignalCorrespondenceRefine( p );    
+    // cleanup
+    Ssw_ManStop( p );
+    return pAigNew;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Performs computation of latch correspondence.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Aig_Man_t * Ssw_LatchCorrespondence( Aig_Man_t * pAig, Ssw_Pars_t * pPars )
+{
+    Ssw_Pars_t Pars;
+    if ( pPars == NULL )
+        Ssw_ManSetDefaultParamsLcorr( pPars = &Pars );
+    return Ssw_SignalCorrespondence( pAig, pPars );
+}
+
+
+////////////////////////////////////////////////////////////////////////
+///                       END OF FILE                                ///
+////////////////////////////////////////////////////////////////////////
+
+
diff --git a/src/aig/ssw_old/sswInt.h b/src/aig/ssw_old/sswInt.h
new file mode 100644
index 00000000..d7bf46a8
--- /dev/null
+++ b/src/aig/ssw_old/sswInt.h
@@ -0,0 +1,232 @@
+/**CFile****************************************************************
+
+  FileName    [sswInt.h]
+
+  SystemName  [ABC: Logic synthesis and verification system.]
+
+  PackageName [Inductive prover with constraints.]
+
+  Synopsis    [External declarations.]
+
+  Author      [Alan Mishchenko]
+  
+  Affiliation [UC Berkeley]
+
+  Date        [Ver. 1.0. Started - September 1, 2008.]
+
+  Revision    [$Id: sswInt.h,v 1.00 2008/09/01 00:00:00 alanmi Exp $]
+
+***********************************************************************/
+ 
+#ifndef __SSW_INT_H__
+#define __SSW_INT_H__
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+////////////////////////////////////////////////////////////////////////
+///                          INCLUDES                                ///
+////////////////////////////////////////////////////////////////////////
+
+#include "saig.h"
+#include "satSolver.h"
+#include "ssw.h"
+
+////////////////////////////////////////////////////////////////////////
+///                         PARAMETERS                               ///
+////////////////////////////////////////////////////////////////////////
+
+////////////////////////////////////////////////////////////////////////
+///                         BASIC TYPES                              ///
+////////////////////////////////////////////////////////////////////////
+
+typedef struct Ssw_Man_t_ Ssw_Man_t; // signal correspondence manager
+typedef struct Ssw_Cla_t_ Ssw_Cla_t; // equivalence classe manager
+typedef struct Ssw_Sml_t_ Ssw_Sml_t; // sequential simulation manager
+
+struct Ssw_Man_t_
+{
+    // parameters
+    Ssw_Pars_t *     pPars;          // parameters
+    int              nFrames;        // for quick lookup
+    // AIGs used in the package
+    Aig_Man_t *      pAig;           // user-given AIG
+    Aig_Man_t *      pFrames;        // final AIG
+    Aig_Obj_t **     pNodeToFrames;  // mapping of AIG nodes into FRAIG nodes
+    // equivalence classes
+    Ssw_Cla_t *      ppClasses;      // equivalence classes of nodes
+    int              fRefined;       // is set to 1 when refinement happens
+    int              nRefUse;        // the number of equivalences used
+    int              nRefSkip;       // the number of equivalences skipped  
+    // SAT solving
+    sat_solver *     pSat;           // recyclable SAT solver
+    int              nSatVars;       // the counter of SAT variables
+    Vec_Int_t *      vSatVars;       // mapping of each node into its SAT var
+    int              nSatVarsTotal;  // the total number of SAT vars created
+    Vec_Ptr_t *      vFanins;        // fanins of the CNF node
+    // SAT solving (latch corr only)
+    Vec_Ptr_t *      vUsedNodes;     // the nodes with SAT variables
+    Vec_Ptr_t *      vUsedPis;       // the PIs with SAT variables
+    Vec_Ptr_t *      vSimInfo;       // simulation information for the framed PIs
+    int              nPatterns;      // the number of patterns saved
+    int              nSimRounds;     // the number of simulation rounds performed
+    int              nCallsCount;    // the number of calls in this round
+    int              nCallsDelta;    // the number of calls to skip
+    int              nCallsSat;      // the number of SAT calls in this round
+    int              nCallsUnsat;    // the number of UNSAT calls in this round
+    int              nRecycleCalls;  // the number of calls since last recycling
+    int              nRecycles;      // the number of time SAT solver was recycled
+    int              nConeMax;       // the maximum cone size
+    // uniqueness
+    Vec_Ptr_t *      vCommon;        // the set of common variables in the logic cones
+    int              iOutputLit;     // the output literal of the uniqueness constaint
+    int              nUniques;       // the number of uniqueness constaints used 
+    // sequential simulator
+    Ssw_Sml_t *      pSml;
+    // counter example storage
+    int              nPatWords;      // the number of words in the counter example
+    unsigned *       pPatWords;      // the counter example
+    unsigned *       pPatWords2;      // the counter example
+    // constraints
+    int              nConstrTotal;   // the number of total constraints
+    int              nConstrReduced; // the number of reduced constraints
+    int              nStrangers;     // the number of strange situations
+    // SAT calls statistics
+    int              nSatCalls;      // the number of SAT calls
+    int              nSatProof;      // the number of proofs
+    int              nSatFailsReal;  // the number of timeouts
+    int              nSatFailsTotal; // the number of timeouts
+    int              nSatCallsUnsat; // the number of unsat SAT calls
+    int              nSatCallsSat;   // the number of sat SAT calls
+    // node/register/lit statistics
+    int              nLitsBeg;
+    int              nLitsEnd;
+    int              nNodesBeg;
+    int              nNodesEnd;
+    int              nRegsBeg;
+    int              nRegsEnd;
+    // runtime stats
+    int              timeBmc;        // bounded model checking
+    int              timeReduce;     // speculative reduction
+    int              timeMarkCones;  // marking the cones not to be refined
+    int              timeSimSat;     // simulation of the counter-examples
+    int              timeSat;        // solving SAT
+    int              timeSatSat;     // sat
+    int              timeSatUnsat;   // unsat
+    int              timeSatUndec;   // undecided
+    int              timeOther;      // other runtime
+    int              timeTotal;      // total runtime
+};
+
+////////////////////////////////////////////////////////////////////////
+///                      MACRO DEFINITIONS                           ///
+////////////////////////////////////////////////////////////////////////
+
+static inline int  Ssw_ObjSatNum( Ssw_Man_t * p, Aig_Obj_t * pObj )             { return Vec_IntEntry( p->vSatVars, pObj->Id );         }
+static inline void Ssw_ObjSetSatNum( Ssw_Man_t * p, Aig_Obj_t * pObj, int Num ) { Vec_IntWriteEntryFill( p->vSatVars, pObj->Id, Num );  }
+
+static inline int  Ssw_ObjIsConst1Cand( Aig_Man_t * pAig, Aig_Obj_t * pObj ) 
+{
+    return Aig_ObjRepr(pAig, pObj) == Aig_ManConst1(pAig);
+}
+static inline void Ssw_ObjSetConst1Cand( Aig_Man_t * pAig, Aig_Obj_t * pObj ) 
+{
+    assert( !Ssw_ObjIsConst1Cand( pAig, pObj ) );
+    Aig_ObjSetRepr( pAig, pObj, Aig_ManConst1(pAig) );
+}
+
+static inline Aig_Obj_t * Ssw_ObjFrame( Ssw_Man_t * p, Aig_Obj_t * pObj, int i )                       { return p->pNodeToFrames[p->nFrames*pObj->Id + i];  }
+static inline void        Ssw_ObjSetFrame( Ssw_Man_t * p, Aig_Obj_t * pObj, int i, Aig_Obj_t * pNode ) { p->pNodeToFrames[p->nFrames*pObj->Id + i] = pNode; }
+
+static inline Aig_Obj_t * Ssw_ObjChild0Fra( Ssw_Man_t * p, Aig_Obj_t * pObj, int i ) { assert( !Aig_IsComplement(pObj) ); return Aig_ObjFanin0(pObj)? Aig_NotCond(Ssw_ObjFrame(p, Aig_ObjFanin0(pObj), i), Aig_ObjFaninC0(pObj)) : NULL;  }
+static inline Aig_Obj_t * Ssw_ObjChild1Fra( Ssw_Man_t * p, Aig_Obj_t * pObj, int i ) { assert( !Aig_IsComplement(pObj) ); return Aig_ObjFanin1(pObj)? Aig_NotCond(Ssw_ObjFrame(p, Aig_ObjFanin1(pObj), i), Aig_ObjFaninC1(pObj)) : NULL;  }
+
+////////////////////////////////////////////////////////////////////////
+///                    FUNCTION DECLARATIONS                         ///
+////////////////////////////////////////////////////////////////////////
+
+/*=== sswAig.c ===================================================*/
+extern Aig_Man_t *   Ssw_FramesWithClasses( Ssw_Man_t * p );
+extern Aig_Man_t *   Ssw_SpeculativeReduction( Ssw_Man_t * p );
+/*=== sswBmc.c ===================================================*/
+extern int           Ssw_FilterUsingBmc( Ssw_Man_t * pMan, int fCheckTargets, int nConfMax, int fVerbose );
+/*=== sswClass.c =================================================*/
+extern Ssw_Cla_t *   Ssw_ClassesStart( Aig_Man_t * pAig );
+extern void          Ssw_ClassesSetData( Ssw_Cla_t * p, void * pManData,
+                         unsigned (*pFuncNodeHash)(void *,Aig_Obj_t *),
+                         int (*pFuncNodeIsConst)(void *,Aig_Obj_t *),
+                         int (*pFuncNodesAreEqual)(void *,Aig_Obj_t *, Aig_Obj_t *) );
+extern void          Ssw_ClassesStop( Ssw_Cla_t * p );
+extern Aig_Man_t *   Ssw_ClassesReadAig( Ssw_Cla_t * p );
+extern Vec_Ptr_t *   Ssw_ClassesGetRefined( Ssw_Cla_t * p );
+extern void          Ssw_ClassesClearRefined( Ssw_Cla_t * p );
+extern int           Ssw_ClassesCand1Num( Ssw_Cla_t * p );
+extern int           Ssw_ClassesClassNum( Ssw_Cla_t * p );
+extern int           Ssw_ClassesLitNum( Ssw_Cla_t * p );
+extern Aig_Obj_t **  Ssw_ClassesReadClass( Ssw_Cla_t * p, Aig_Obj_t * pRepr, int * pnSize );
+extern void          Ssw_ClassesCollectClass( Ssw_Cla_t * p, Aig_Obj_t * pRepr, Vec_Ptr_t * vClass );
+extern void          Ssw_ClassesCheck( Ssw_Cla_t * p );
+extern void          Ssw_ClassesPrint( Ssw_Cla_t * p, int fVeryVerbose );
+extern void          Ssw_ClassesRemoveNode( Ssw_Cla_t * p, Aig_Obj_t * pObj );
+extern Ssw_Cla_t *   Ssw_ClassesPrepare( Aig_Man_t * pAig, int fLatchCorr, int nMaxLevs, int fVerbose );
+extern Ssw_Cla_t *   Ssw_ClassesPrepareSimple( Aig_Man_t * pAig, int fLatchCorr, int nMaxLevs );
+extern Ssw_Cla_t *   Ssw_ClassesPrepareTargets( Aig_Man_t * pAig );
+extern Ssw_Cla_t *   Ssw_ClassesPreparePairs( Aig_Man_t * pAig, Vec_Int_t ** pvClasses );
+extern int           Ssw_ClassesRefine( Ssw_Cla_t * p, int fRecursive );
+extern int           Ssw_ClassesRefineOneClass( Ssw_Cla_t * p, Aig_Obj_t * pRepr, int fRecursive );
+extern int           Ssw_ClassesRefineConst1Group( Ssw_Cla_t * p, Vec_Ptr_t * vRoots, int fRecursive );
+extern int           Ssw_ClassesRefineConst1( Ssw_Cla_t * p, int fRecursive );
+/*=== sswCnf.c ===================================================*/
+extern void          Ssw_CnfNodeAddToSolver( Ssw_Man_t * p, Aig_Obj_t * pObj );
+/*=== sswCore.c ===================================================*/
+extern Aig_Man_t *   Ssw_SignalCorrespondenceRefine( Ssw_Man_t * p );
+/*=== sswLcorr.c ==========================================================*/
+extern int           Ssw_ManSweepLatch( Ssw_Man_t * p );
+/*=== sswMan.c ===================================================*/
+extern Ssw_Man_t *   Ssw_ManCreate( Aig_Man_t * pAig, Ssw_Pars_t * pPars );
+extern void          Ssw_ManCleanup( Ssw_Man_t * p );
+extern void          Ssw_ManStop( Ssw_Man_t * p );
+extern void          Ssw_ManStartSolver( Ssw_Man_t * p );
+/*=== sswSat.c ===================================================*/
+extern int           Ssw_NodesAreEquiv( Ssw_Man_t * p, Aig_Obj_t * pOld, Aig_Obj_t * pNew );
+extern int           Ssw_NodesAreConstrained( Ssw_Man_t * p, Aig_Obj_t * pOld, Aig_Obj_t * pNew );
+/*=== sswSim.c ===================================================*/
+extern unsigned      Ssw_SmlObjHashWord( Ssw_Sml_t * p, Aig_Obj_t * pObj );
+extern int           Ssw_SmlObjIsConstWord( Ssw_Sml_t * p, Aig_Obj_t * pObj );
+extern int           Ssw_SmlObjsAreEqualWord( Ssw_Sml_t * p, Aig_Obj_t * pObj0, Aig_Obj_t * pObj1 );
+extern int           Ssw_SmlObjIsConstBit( void * p, Aig_Obj_t * pObj );
+extern int           Ssw_SmlObjsAreEqualBit( void * p, Aig_Obj_t * pObj0, Aig_Obj_t * pObj1 );
+extern Ssw_Sml_t *   Ssw_SmlStart( Aig_Man_t * pAig, int nPref, int nFrames, int nWordsFrame );
+extern void          Ssw_SmlClean( Ssw_Sml_t * p );
+extern void          Ssw_SmlStop( Ssw_Sml_t * p );
+extern void          Ssw_SmlObjAssignConst( Ssw_Sml_t * p, Aig_Obj_t * pObj, int fConst1, int iFrame );
+extern unsigned      Ssw_SmlObjGetWord( Ssw_Sml_t * p, Aig_Obj_t * pObj, int iWord, int iFrame );
+extern void          Ssw_SmlObjSetWord( Ssw_Sml_t * p, Aig_Obj_t * pObj, unsigned Word, int iWord, int iFrame );
+extern void          Ssw_SmlAssignDist1Plus( Ssw_Sml_t * p, unsigned * pPat );
+extern void          Ssw_SmlSimulateOne( Ssw_Sml_t * p );
+extern void          Ssw_SmlSimulateOneFrame( Ssw_Sml_t * p );
+extern Ssw_Sml_t *   Ssw_SmlSimulateSeq( Aig_Man_t * pAig, int nPref, int nFrames, int nWords );
+/*=== sswSimSat.c ===================================================*/
+extern void          Ssw_ManResimulateBit( Ssw_Man_t * p, Aig_Obj_t * pObj, Aig_Obj_t * pRepr );
+extern void          Ssw_ManResimulateWord( Ssw_Man_t * p, Aig_Obj_t * pCand, Aig_Obj_t * pRepr, int f );
+extern void          Ssw_ManResimulateWord2( Ssw_Man_t * p, Aig_Obj_t * pCand, Aig_Obj_t * pRepr, int f );
+/*=== sswSweep.c ===================================================*/
+extern int           Ssw_ManGetSatVarValue( Ssw_Man_t * p, Aig_Obj_t * pObj, int f );
+extern int           Ssw_ManSweepNode( Ssw_Man_t * p, Aig_Obj_t * pObj, int f, int fBmc );
+extern int           Ssw_ManSweepBmc( Ssw_Man_t * p );
+extern int           Ssw_ManSweep( Ssw_Man_t * p );
+/*=== sswUnique.c ===================================================*/
+extern int           Ssw_ManUniqueOne( Ssw_Man_t * p, Aig_Obj_t * pRepr, Aig_Obj_t * pObj );
+extern int           Ssw_ManUniqueAddConstraint( Ssw_Man_t * p, Vec_Ptr_t * vCommon, int f1, int f2 );
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
+
+////////////////////////////////////////////////////////////////////////
+///                       END OF FILE                                ///
+////////////////////////////////////////////////////////////////////////
+
diff --git a/src/aig/ssw_old/sswLcorr.c b/src/aig/ssw_old/sswLcorr.c
new file mode 100644
index 00000000..cde9b0c9
--- /dev/null
+++ b/src/aig/ssw_old/sswLcorr.c
@@ -0,0 +1,364 @@
+/**CFile****************************************************************
+
+  FileName    [sswLcorr.c]
+
+  SystemName  [ABC: Logic synthesis and verification system.]
+
+  PackageName [Inductive prover with constraints.]
+
+  Synopsis    [Latch correspondence.]
+
+  Author      [Alan Mishchenko]
+  
+  Affiliation [UC Berkeley]
+
+  Date        [Ver. 1.0. Started - September 1, 2008.]
+
+  Revision    [$Id: sswLcorr.c,v 1.00 2008/09/01 00:00:00 alanmi Exp $]
+
+***********************************************************************/
+
+#include "sswInt.h"
+//#include "bar.h"
+
+////////////////////////////////////////////////////////////////////////
+///                        DECLARATIONS                              ///
+////////////////////////////////////////////////////////////////////////
+
+////////////////////////////////////////////////////////////////////////
+///                     FUNCTION DEFINITIONS                         ///
+////////////////////////////////////////////////////////////////////////
+
+/**Function*************************************************************
+
+  Synopsis    [Recycles the SAT solver.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ssw_ManSatSolverRecycle( Ssw_Man_t * p )
+{
+    int Lit;
+    if ( p->pSat )
+    {
+        Aig_Obj_t * pObj;
+        int i;
+        Vec_PtrForEachEntry( p->vUsedNodes, pObj, i )
+            Ssw_ObjSetSatNum( p, pObj, 0 );
+        Vec_PtrClear( p->vUsedNodes );
+        Vec_PtrClear( p->vUsedPis );
+//        memset( p->pSatVars, 0, sizeof(int) * Aig_ManObjNumMax(p->pAigTotal) );
+        sat_solver_delete( p->pSat );
+    }
+    p->pSat = sat_solver_new();
+    sat_solver_setnvars( p->pSat, 1000 );
+    // var 0 is not used
+    // var 1 is reserved for const1 node - add the clause
+    p->nSatVars = 1;
+//    p->nSatVars = 0;
+    Lit = toLit( p->nSatVars );
+    if ( p->pPars->fPolarFlip )
+        Lit = lit_neg( Lit );
+    sat_solver_addclause( p->pSat, &Lit, &Lit + 1 );
+    Ssw_ObjSetSatNum( p, Aig_ManConst1(p->pFrames), p->nSatVars++ );
+
+    p->nRecycles++;
+    p->nRecycleCalls = 0;
+}
+
+
+/**Function*************************************************************
+
+  Synopsis    [Tranfers simulation information from FRAIG to AIG.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ssw_ManSweepTransfer( Ssw_Man_t * p )
+{
+    Aig_Obj_t * pObj, * pObjFraig;
+    unsigned * pInfo;
+    int i;
+    // transfer simulation information
+    Aig_ManForEachPi( p->pAig, pObj, i )
+    {
+        pObjFraig = Ssw_ObjFrame( p, pObj, 0 );
+        if ( pObjFraig == Aig_ManConst0(p->pFrames) )
+        {
+            Ssw_SmlObjAssignConst( p->pSml, pObj, 0, 0 );
+            continue;
+        }
+        assert( !Aig_IsComplement(pObjFraig) );
+        assert( Aig_ObjIsPi(pObjFraig) );
+        pInfo = Vec_PtrEntry( p->vSimInfo, Aig_ObjPioNum(pObjFraig) );
+        Ssw_SmlObjSetWord( p->pSml, pObj, pInfo[0], 0, 0 );
+    }
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Performs one round of simulation with counter-examples.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Ssw_ManSweepResimulate( Ssw_Man_t * p )
+{
+    int RetValue1, RetValue2, clk = clock();
+    // transfer PI simulation information from storage
+    Ssw_ManSweepTransfer( p );
+    // simulate internal nodes
+    Ssw_SmlSimulateOneFrame( p->pSml );
+    // check equivalence classes
+    RetValue1 = Ssw_ClassesRefineConst1( p->ppClasses, 1 );
+    RetValue2 = Ssw_ClassesRefine( p->ppClasses, 1 );
+    // prepare simulation info for the next round
+    Vec_PtrCleanSimInfo( p->vSimInfo, 0, 1 );
+    p->nPatterns = 0;
+    p->nSimRounds++;
+p->timeSimSat += clock() - clk;
+    return RetValue1 > 0 || RetValue2 > 0;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Saves one counter-example into internal storage.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ssw_SmlAddPattern( Ssw_Man_t * p, Aig_Obj_t * pRepr, Aig_Obj_t * pCand )
+{
+    Aig_Obj_t * pObj;
+    unsigned * pInfo;
+    int i, nVarNum, Value;
+    Vec_PtrForEachEntry( p->vUsedPis, pObj, i )
+    {
+        nVarNum = Ssw_ObjSatNum( p, pObj );
+        assert( nVarNum > 0 );
+        Value = sat_solver_var_value( p->pSat, nVarNum );
+        if ( Value == 0 )
+            continue;
+        pInfo = Vec_PtrEntry( p->vSimInfo, Aig_ObjPioNum(pObj) );
+        Aig_InfoSetBit( pInfo, p->nPatterns );
+    }
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Builds fraiged logic cone of the node.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ssw_ManBuildCone_rec( Ssw_Man_t * p, Aig_Obj_t * pObj )
+{
+    Aig_Obj_t * pObjNew;
+    assert( !Aig_IsComplement(pObj) );
+    if ( Ssw_ObjFrame( p, pObj, 0 ) )
+        return;
+    assert( Aig_ObjIsNode(pObj) );
+    Ssw_ManBuildCone_rec( p, Aig_ObjFanin0(pObj) );
+    Ssw_ManBuildCone_rec( p, Aig_ObjFanin1(pObj) );
+    pObjNew = Aig_And( p->pFrames, Ssw_ObjChild0Fra(p, pObj, 0), Ssw_ObjChild1Fra(p, pObj, 0) );
+    Ssw_ObjSetFrame( p, pObj, 0, pObjNew );
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Recycles the SAT solver.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ssw_ManSweepLatchOne( Ssw_Man_t * p, Aig_Obj_t * pObjRepr, Aig_Obj_t * pObj )
+{
+    Aig_Obj_t * pObjFraig, * pObjReprFraig, * pObjLi;
+    int RetValue, clk;
+    assert( Aig_ObjIsPi(pObj) );
+    assert( Aig_ObjIsPi(pObjRepr) || Aig_ObjIsConst1(pObjRepr) );
+    // check if it makes sense to skip some calls
+    if ( p->nCallsCount > 100 && p->nCallsUnsat < p->nCallsSat )
+    {
+        if ( ++p->nCallsDelta < 0 )
+            return;
+    }
+    p->nCallsDelta = 0;
+clk = clock();
+    // get the fraiged node
+    pObjLi = Saig_ObjLoToLi( p->pAig, pObj ); 
+    Ssw_ManBuildCone_rec( p, Aig_ObjFanin0(pObjLi) );
+    pObjFraig = Ssw_ObjChild0Fra( p, pObjLi, 0 );
+    // get the fraiged representative
+    if ( Aig_ObjIsPi(pObjRepr) )
+    {
+        pObjLi = Saig_ObjLoToLi( p->pAig, pObjRepr ); 
+        Ssw_ManBuildCone_rec( p, Aig_ObjFanin0(pObjLi) );
+        pObjReprFraig = Ssw_ObjChild0Fra( p, pObjLi, 0 );
+    }
+    else 
+        pObjReprFraig = Ssw_ObjFrame( p, pObjRepr, 0 );
+p->timeReduce += clock() - clk;
+    // if the fraiged nodes are the same, return
+    if ( Aig_Regular(pObjFraig) == Aig_Regular(pObjReprFraig) )
+        return;
+    p->nRecycleCalls++;
+    p->nCallsCount++;
+
+    // check equivalence of the two nodes
+    if ( (pObj->fPhase == pObjRepr->fPhase) != (Aig_ObjPhaseReal(pObjFraig) == Aig_ObjPhaseReal(pObjReprFraig)) )
+    {
+        p->nPatterns++;
+        p->nStrangers++;
+        p->fRefined = 1;
+    }
+    else
+    { 
+        RetValue = Ssw_NodesAreEquiv( p, Aig_Regular(pObjReprFraig), Aig_Regular(pObjFraig) );
+        if ( RetValue == 1 )  // proved equivalence
+        {
+            p->nCallsUnsat++;
+            return;
+        }
+        if ( RetValue == -1 ) // timed out
+        {
+            Ssw_ClassesRemoveNode( p->ppClasses, pObj );
+            p->nCallsUnsat++;
+            p->fRefined = 1;
+            return;
+        }
+        else // disproved equivalence
+        {       
+            Ssw_SmlAddPattern( p, pObjRepr, pObj );
+            p->nPatterns++;
+            p->nCallsSat++;
+            p->fRefined = 1;
+        }
+    }
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Performs one iteration of sweeping latches.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Ssw_ManSweepLatch( Ssw_Man_t * p )
+{
+//    Bar_Progress_t * pProgress = NULL;
+    Vec_Ptr_t * vClass;
+    Aig_Obj_t * pObj, * pRepr, * pTemp;
+    int i, k;
+
+    // start the timeframe
+    p->pFrames = Aig_ManStart( Aig_ManObjNumMax(p->pAig) );
+    // map constants and PIs
+    Ssw_ObjSetFrame( p, Aig_ManConst1(p->pAig), 0, Aig_ManConst1(p->pFrames) );
+    Saig_ManForEachPi( p->pAig, pObj, i )
+        Ssw_ObjSetFrame( p, pObj, 0, Aig_ObjCreatePi(p->pFrames) );
+
+    // implement equivalence classes
+    Saig_ManForEachLo( p->pAig, pObj, i )
+    {
+        pRepr = Aig_ObjRepr( p->pAig, pObj );
+        if ( pRepr == NULL )
+        {
+            pTemp = Aig_ObjCreatePi(p->pFrames);
+            pTemp->pData = pObj;
+        }
+        else
+            pTemp = Aig_NotCond( Ssw_ObjFrame(p, pRepr, 0), pRepr->fPhase ^ pObj->fPhase );
+        Ssw_ObjSetFrame( p, pObj, 0, pTemp );
+    }
+    Aig_ManSetPioNumbers( p->pFrames );
+
+    // prepare simulation info
+    assert( p->vSimInfo == NULL );
+    p->vSimInfo = Vec_PtrAllocSimInfo( Aig_ManPiNum(p->pFrames), 1 );
+    Vec_PtrCleanSimInfo( p->vSimInfo, 0, 1 );
+
+    // go through the registers
+//    if ( p->pPars->fVerbose )
+//        pProgress = Bar_ProgressStart( stdout, Aig_ManRegNum(p->pAig) );
+    vClass = Vec_PtrAlloc( 100 );
+    p->fRefined = 0;
+    p->nCallsCount = p->nCallsSat = p->nCallsUnsat = 0;
+    Saig_ManForEachLo( p->pAig, pObj, i )
+    {
+//        if ( p->pPars->fVerbose )
+//            Bar_ProgressUpdate( pProgress, i, NULL );
+        // consider the case of constant candidate
+        if ( Ssw_ObjIsConst1Cand( p->pAig, pObj ) )
+            Ssw_ManSweepLatchOne( p, Aig_ManConst1(p->pAig), pObj );
+        else
+        {
+            // consider the case of equivalence class
+            Ssw_ClassesCollectClass( p->ppClasses, pObj, vClass );
+            if ( Vec_PtrSize(vClass) == 0 )
+                continue;
+            // try to prove equivalences in this class
+            Vec_PtrForEachEntry( vClass, pTemp, k )
+                if ( Aig_ObjRepr(p->pAig, pTemp) == pObj )
+                {
+                    Ssw_ManSweepLatchOne( p, pObj, pTemp );
+                    if ( p->nPatterns == 32 )
+                        break;
+                }
+        }
+        // resimulate
+        if ( p->nPatterns == 32 )
+            Ssw_ManSweepResimulate( p );
+        // attempt recycling the SAT solver
+        if ( p->pPars->nSatVarMax && 
+             p->nSatVars > p->pPars->nSatVarMax &&
+             p->nRecycleCalls > p->pPars->nRecycleCalls )
+             Ssw_ManSatSolverRecycle( p );
+    }
+    // resimulate
+    if ( p->nPatterns > 0 )
+        Ssw_ManSweepResimulate( p );
+    // cleanup
+    Vec_PtrFree( vClass );
+    p->nSatFailsTotal += p->nSatFailsReal;
+//    if ( p->pPars->fVerbose )
+//        Bar_ProgressStop( pProgress );
+
+    // cleanup
+//    Ssw_ClassesCheck( p->ppClasses );
+    return p->fRefined;
+}
+
+////////////////////////////////////////////////////////////////////////
+///                       END OF FILE                                ///
+////////////////////////////////////////////////////////////////////////
+
+
diff --git a/src/aig/ssw_old/sswMan.c b/src/aig/ssw_old/sswMan.c
new file mode 100644
index 00000000..84b041b4
--- /dev/null
+++ b/src/aig/ssw_old/sswMan.c
@@ -0,0 +1,237 @@
+/**CFile****************************************************************
+
+  FileName    [sswMan.c]
+
+  SystemName  [ABC: Logic synthesis and verification system.]
+
+  PackageName [Inductive prover with constraints.]
+
+  Synopsis    [Calls to the SAT solver.]
+
+  Author      [Alan Mishchenko]
+  
+  Affiliation [UC Berkeley]
+
+  Date        [Ver. 1.0. Started - September 1, 2008.]
+
+  Revision    [$Id: sswMan.c,v 1.00 2008/09/01 00:00:00 alanmi Exp $]
+
+***********************************************************************/
+
+#include "sswInt.h"
+
+////////////////////////////////////////////////////////////////////////
+///                        DECLARATIONS                              ///
+////////////////////////////////////////////////////////////////////////
+
+////////////////////////////////////////////////////////////////////////
+///                     FUNCTION DEFINITIONS                         ///
+////////////////////////////////////////////////////////////////////////
+
+/**Function*************************************************************
+
+  Synopsis    [Creates the manager.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Ssw_Man_t * Ssw_ManCreate( Aig_Man_t * pAig, Ssw_Pars_t * pPars )
+{
+    Ssw_Man_t * p;
+    // prepare the sequential AIG
+    assert( Saig_ManRegNum(pAig) > 0 );
+    Aig_ManFanoutStart( pAig );
+    Aig_ManSetPioNumbers( pAig );
+    // create interpolation manager
+    p = ALLOC( Ssw_Man_t, 1 ); 
+    memset( p, 0, sizeof(Ssw_Man_t) );
+    p->pPars         = pPars;
+    p->pAig          = pAig;
+    p->nFrames       = pPars->nFramesK + 1;
+    p->pNodeToFrames = CALLOC( Aig_Obj_t *, Aig_ManObjNumMax(p->pAig) * p->nFrames );
+    // SAT solving
+    p->vSatVars      = Vec_IntStart( Aig_ManObjNumMax(p->pAig) * (p->nFrames+1) );
+    p->vFanins       = Vec_PtrAlloc( 100 );
+    // SAT solving (latch corr only)
+    p->vUsedNodes    = Vec_PtrAlloc( 1000 );
+    p->vUsedPis      = Vec_PtrAlloc( 1000 );
+    p->vCommon       = Vec_PtrAlloc( 100 );
+    p->iOutputLit    = -1;
+    // allocate storage for sim pattern
+    p->nPatWords     = Aig_BitWordNum( Saig_ManPiNum(pAig) * p->nFrames + Saig_ManRegNum(pAig) );
+    p->pPatWords     = ALLOC( unsigned, p->nPatWords ); 
+    p->pPatWords2     = ALLOC( unsigned, p->nPatWords ); 
+    return p;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Prints stats of the manager.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Ssw_ManCountEquivs( Ssw_Man_t * p )
+{
+    Aig_Obj_t * pObj;
+    int i, nEquivs = 0;
+    Aig_ManForEachObj( p->pAig, pObj, i )
+        nEquivs += ( Aig_ObjRepr(p->pAig, pObj) != NULL );
+    return nEquivs;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Prints stats of the manager.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ssw_ManPrintStats( Ssw_Man_t * p )
+{
+    double nMemory = 1.0*Aig_ManObjNumMax(p->pAig)*p->nFrames*(2*sizeof(int)+2*sizeof(void*))/(1<<20);
+
+    printf( "Parameters: F = %d. AddF = %d. C-lim = %d. Constr = %d. MaxLev = %d. Mem = %0.2f Mb.\n", 
+        p->pPars->nFramesK, p->pPars->nFramesAddSim, p->pPars->nBTLimit, p->pPars->nConstrs, p->pPars->nMaxLevs, nMemory );
+    printf( "AIG       : PI = %d. PO = %d. Latch = %d. Node = %d.  Ave SAT vars = %d.\n", 
+        Saig_ManPiNum(p->pAig), Saig_ManPoNum(p->pAig), Saig_ManRegNum(p->pAig), Aig_ManNodeNum(p->pAig), 
+        p->nSatVarsTotal/p->pPars->nIters );
+    printf( "SAT calls : Proof = %d. Cex = %d. Fail = %d. Equivs = %d. Str = %d.\n", 
+        p->nSatProof, p->nSatCallsSat, p->nSatFailsTotal, Ssw_ManCountEquivs(p), p->nStrangers );
+    printf( "SAT solver: Vars = %d. Max cone = %d. Recycles = %d. Rounds = %d.\n", 
+        p->nSatVars, p->nConeMax, p->nRecycles, p->nSimRounds );
+    printf( "NBeg = %d. NEnd = %d. (Gain = %6.2f %%).  RBeg = %d. REnd = %d. (Gain = %6.2f %%).\n", 
+        p->nNodesBeg, p->nNodesEnd, 100.0*(p->nNodesBeg-p->nNodesEnd)/(p->nNodesBeg?p->nNodesBeg:1), 
+        p->nRegsBeg, p->nRegsEnd, 100.0*(p->nRegsBeg-p->nRegsEnd)/(p->nRegsBeg?p->nRegsBeg:1) );
+
+    p->timeOther = p->timeTotal-p->timeBmc-p->timeReduce-p->timeMarkCones-p->timeSimSat-p->timeSat;
+    PRTP( "BMC        ", p->timeBmc,       p->timeTotal );
+    PRTP( "Spec reduce", p->timeReduce,    p->timeTotal );
+    PRTP( "Mark cones ", p->timeMarkCones, p->timeTotal );
+    PRTP( "Sim SAT    ", p->timeSimSat,    p->timeTotal );
+    PRTP( "SAT solving", p->timeSat,       p->timeTotal );
+    PRTP( "  unsat    ", p->timeSatUnsat,  p->timeTotal );
+    PRTP( "  sat      ", p->timeSatSat,    p->timeTotal );
+    PRTP( "  undecided", p->timeSatUndec,  p->timeTotal );
+    PRTP( "Other      ", p->timeOther,     p->timeTotal );
+    PRTP( "TOTAL      ", p->timeTotal,     p->timeTotal );
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Frees the manager.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ssw_ManCleanup( Ssw_Man_t * p )
+{
+    if ( p->pFrames )
+    {
+        Aig_ManStop( p->pFrames );
+        p->pFrames = NULL;
+        memset( p->pNodeToFrames, 0, sizeof(Aig_Obj_t *) * Aig_ManObjNumMax(p->pAig) * p->nFrames );
+    }
+    if ( p->pSat )
+    {
+        int i;
+//        printf( "Vars = %d. Clauses = %d. Learnts = %d.\n", p->pSat->size, p->pSat->clauses.size, p->pSat->learnts.size );
+        p->nSatVarsTotal += p->pSat->size;
+        sat_solver_delete( p->pSat );
+        p->pSat = NULL;
+//        memset( p->pSatVars, 0, sizeof(int) * Aig_ManObjNumMax(p->pAig) * (p->nFrames+1) );
+        for ( i = 0; i < Vec_IntSize(p->vSatVars); i++ )
+            p->vSatVars->pArray[i] = 0;
+    }
+    if ( p->vSimInfo )  
+    {
+        Vec_PtrFree( p->vSimInfo );
+        p->vSimInfo = NULL;
+    }
+    p->nConstrTotal = 0;
+    p->nConstrReduced = 0;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Frees the manager.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ssw_ManStop( Ssw_Man_t * p )
+{
+    Aig_ManCleanMarkA( p->pAig );
+    Aig_ManCleanMarkB( p->pAig );
+    if ( p->pPars->fVerbose )
+        Ssw_ManPrintStats( p );
+    if ( p->ppClasses )
+        Ssw_ClassesStop( p->ppClasses );
+    if ( p->pSml )      
+        Ssw_SmlStop( p->pSml );
+    Vec_PtrFree( p->vFanins );
+    Vec_PtrFree( p->vUsedNodes );
+    Vec_PtrFree( p->vUsedPis );
+    Vec_IntFree( p->vSatVars );
+    Vec_PtrFree( p->vCommon );
+    FREE( p->pNodeToFrames );
+    FREE( p->pPatWords );
+    FREE( p->pPatWords2 );
+    free( p );
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Starts the SAT solver.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ssw_ManStartSolver( Ssw_Man_t * p )
+{
+    int Lit;
+    assert( p->pSat == NULL );
+    p->pSat = sat_solver_new();
+    sat_solver_setnvars( p->pSat, 1000 );
+    // var 0 is not used
+    // var 1 is reserved for const1 node - add the clause
+    p->nSatVars = 1;
+    Lit = toLit( p->nSatVars );
+    if ( p->pPars->fPolarFlip )
+        Lit = lit_neg( Lit );
+    sat_solver_addclause( p->pSat, &Lit, &Lit + 1 );
+    Ssw_ObjSetSatNum( p, Aig_ManConst1(p->pAig), p->nSatVars++ );
+
+    Vec_PtrClear( p->vUsedNodes );
+    Vec_PtrClear( p->vUsedPis );
+}
+
+////////////////////////////////////////////////////////////////////////
+///                       END OF FILE                                ///
+////////////////////////////////////////////////////////////////////////
+
+
diff --git a/src/aig/ssw_old/sswPairs.c b/src/aig/ssw_old/sswPairs.c
new file mode 100644
index 00000000..c77ad30d
--- /dev/null
+++ b/src/aig/ssw_old/sswPairs.c
@@ -0,0 +1,470 @@
+/**CFile****************************************************************
+
+  FileName    [sswPairs.c]
+
+  SystemName  [ABC: Logic synthesis and verification system.]
+
+  PackageName [Inductive prover with constraints.]
+
+  Synopsis    [Calls to the SAT solver.]
+
+  Author      [Alan Mishchenko]
+  
+  Affiliation [UC Berkeley]
+
+  Date        [Ver. 1.0. Started - September 1, 2008.]
+
+  Revision    [$Id: sswPairs.c,v 1.00 2008/09/01 00:00:00 alanmi Exp $]
+
+***********************************************************************/
+
+#include "sswInt.h"
+
+////////////////////////////////////////////////////////////////////////
+///                        DECLARATIONS                              ///
+////////////////////////////////////////////////////////////////////////
+
+////////////////////////////////////////////////////////////////////////
+///                     FUNCTION DEFINITIONS                         ///
+////////////////////////////////////////////////////////////////////////
+
+/**Function*************************************************************
+
+  Synopsis    [Reports the status of the miter.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Ssw_MiterStatus( Aig_Man_t * p, int fVerbose )
+{
+    Aig_Obj_t * pObj, * pChild;
+    int i, CountConst0 = 0, CountNonConst0 = 0, CountUndecided = 0;
+//    if ( p->pData )
+//        return 0;
+    Saig_ManForEachPo( p, pObj, i )
+    {
+        pChild = Aig_ObjChild0(pObj);
+        // check if the output is constant 0
+        if ( pChild == Aig_ManConst0(p) )
+        {
+            CountConst0++;
+            continue;
+        }
+        // check if the output is constant 1
+        if ( pChild == Aig_ManConst1(p) )
+        {
+            CountNonConst0++;
+            continue;
+        }
+        // check if the output is a primary input
+        if ( p->nRegs == 0 && Aig_ObjIsPi(Aig_Regular(pChild)) )
+        {
+            CountNonConst0++;
+            continue;
+        }
+        // check if the output can be not constant 0
+        if ( Aig_Regular(pChild)->fPhase != (unsigned)Aig_IsComplement(pChild) )
+        {
+            CountNonConst0++;
+            continue;
+        }
+        CountUndecided++;
+    }
+
+    if ( fVerbose )
+    {
+        printf( "Miter has %d outputs. ", Saig_ManPoNum(p) );
+        printf( "Const0 = %d.  ", CountConst0 );
+        printf( "NonConst0 = %d.  ", CountNonConst0 );
+        printf( "Undecided = %d.  ", CountUndecided );
+        printf( "\n" );
+    }
+
+    if ( CountNonConst0 )
+        return 0;
+    if ( CountUndecided )
+        return -1;
+    return 1;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Transfer equivalent pairs to the miter.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Vec_Int_t * Ssw_TransferSignalPairs( Aig_Man_t * pMiter, Aig_Man_t * pAig1, Aig_Man_t * pAig2, Vec_Int_t * vIds1, Vec_Int_t * vIds2 )
+{
+    Vec_Int_t * vIds;
+    Aig_Obj_t * pObj1, * pObj2;
+    Aig_Obj_t * pObj1m, * pObj2m;
+    int i;
+    vIds = Vec_IntAlloc( 2 * Vec_IntSize(vIds1) );
+    for ( i = 0; i < Vec_IntSize(vIds1); i++ )
+    {
+        pObj1 = Aig_ManObj( pAig1, Vec_IntEntry(vIds1, i) );
+        pObj2 = Aig_ManObj( pAig2, Vec_IntEntry(vIds2, i) );
+        pObj1m = Aig_Regular(pObj1->pData);
+        pObj2m = Aig_Regular(pObj2->pData);
+        assert( pObj1m && pObj2m );
+        if ( pObj1m == pObj2m )
+            continue;
+        if ( pObj1m->Id < pObj2m->Id )
+        {
+            Vec_IntPush( vIds, pObj1m->Id );
+            Vec_IntPush( vIds, pObj2m->Id );
+        }
+        else
+        {
+            Vec_IntPush( vIds, pObj2m->Id );
+            Vec_IntPush( vIds, pObj1m->Id );
+        }
+    }
+    return vIds;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Transform pairs into class representation.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Vec_Int_t ** Ssw_TransformPairsIntoTempClasses( Vec_Int_t * vPairs, int nObjNumMax )
+{
+    Vec_Int_t ** pvClasses;   // vector of classes
+    int * pReprs;             // mapping nodes into their representatives
+    int Entry, idObj, idRepr, idReprObj, idReprRepr, i;
+    // allocate data-structures
+    pvClasses = CALLOC( Vec_Int_t *, nObjNumMax );
+    pReprs    = ALLOC( int, nObjNumMax );
+    for ( i = 0; i < nObjNumMax; i++ )
+        pReprs[i] = -1;
+    // consider pairs
+    for ( i = 0; i < Vec_IntSize(vPairs); i += 2 )
+    {
+        // get both objects
+        idRepr = Vec_IntEntry( vPairs, i   );
+        idObj  = Vec_IntEntry( vPairs, i+1 );
+        assert( idObj > 0 );
+        assert( (pReprs[idRepr] == -1) || (pvClasses[pReprs[idRepr]] != NULL) );
+        assert( (pReprs[idObj]  == -1) || (pvClasses[pReprs[idObj] ] != NULL) );
+        // get representatives of both objects
+        idReprRepr = pReprs[idRepr];
+        idReprObj  = pReprs[idObj];
+        // check different situations
+        if ( idReprRepr == -1 && idReprObj == -1 )
+        {   // they do not have classes
+            // create a class
+            pvClasses[idRepr] = Vec_IntAlloc( 4 );
+            Vec_IntPush( pvClasses[idRepr], idRepr );
+            Vec_IntPush( pvClasses[idRepr], idObj );
+            pReprs[ idRepr ] = idRepr;
+            pReprs[ idObj  ] = idRepr;
+        }
+        else if ( idReprRepr >= 0 && idReprObj == -1 )
+        {   // representative has a class
+            // add iObj to the same class
+            Vec_IntPushUniqueOrder( pvClasses[idReprRepr], idObj );
+            pReprs[ idObj ] = idReprRepr;
+        }
+        else if ( idReprRepr == -1 && idReprObj >= 0 )
+        {   // object has a class
+            assert( idReprObj != idRepr );
+            if ( idReprObj < idRepr ) 
+            { // add idRepr to the same class
+                Vec_IntPushUniqueOrder( pvClasses[idReprObj], idRepr );
+                pReprs[ idRepr ] = idReprObj;
+            }
+            else // if ( idReprObj > idRepr ) 
+            { // make idRepr new representative
+                Vec_IntPushFirst( pvClasses[idReprObj], idRepr );
+                pvClasses[idRepr] = pvClasses[idReprObj];
+                pvClasses[idReprObj] = NULL;
+                // set correct representatives of each node
+                Vec_IntForEachEntry( pvClasses[idRepr], Entry, i )
+                    pReprs[ Entry ] = idRepr;
+            }
+        }
+        else // if ( idReprRepr >= 0 && idReprObj >= 0 )
+        {   // both have classes
+            if ( idReprRepr == idReprObj )
+            {  // the classes are the same
+                // nothing to do
+            }
+            else
+            {  // the classes are different
+                // find the repr of the new class
+                if ( idReprRepr < idReprObj )
+                {
+                    Vec_IntForEachEntry( pvClasses[idReprObj], Entry, i )
+                    {
+                        Vec_IntPushUniqueOrder( pvClasses[idReprRepr], Entry );
+                        pReprs[ Entry ] = idReprRepr;
+                    }
+                    Vec_IntFree( pvClasses[idReprObj] );
+                    pvClasses[idReprObj] = NULL;
+                }
+                else // if ( idReprRepr > idReprObj )
+                {
+                    Vec_IntForEachEntry( pvClasses[idReprRepr], Entry, i )
+                    {
+                        Vec_IntPushUniqueOrder( pvClasses[idReprObj], Entry );
+                        pReprs[ Entry ] = idReprObj;
+                    }
+                    Vec_IntFree( pvClasses[idReprRepr] );
+                    pvClasses[idReprRepr] = NULL;
+                }
+            }
+        }
+    }
+    free( pReprs );
+    return pvClasses;
+}
+
+/**Function*************************************************************
+
+  Synopsis    []
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ssw_FreeTempClasses( Vec_Int_t ** pvClasses, int nObjNumMax )
+{
+    int i;
+    for ( i = 0; i < nObjNumMax; i++ )
+        if ( pvClasses[i] ) 
+            Vec_IntFree( pvClasses[i] );
+    free( pvClasses );
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Performs signal correspondence for the miter of two AIGs with node pairs defined.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Aig_Man_t * Ssw_SignalCorrespondenceWithPairs( Aig_Man_t * pAig1, Aig_Man_t * pAig2, Vec_Int_t * vIds1, Vec_Int_t * vIds2, Ssw_Pars_t * pPars )
+{
+    Ssw_Man_t * p; 
+    Aig_Man_t * pAigNew, * pMiter;
+    Ssw_Pars_t Pars;
+    Vec_Int_t * vPairs;
+    Vec_Int_t ** pvClasses;
+    assert( Vec_IntSize(vIds1) == Vec_IntSize(vIds2) );
+    // create sequential miter
+    pMiter = Saig_ManCreateMiter( pAig1, pAig2, 0 );
+    // transfer information to the miter
+    vPairs = Ssw_TransferSignalPairs( pMiter, pAig1, pAig2, vIds1, vIds2 );
+    // create representation of the classes
+    pvClasses = Ssw_TransformPairsIntoTempClasses( vPairs, Aig_ManObjNumMax(pMiter) );
+    Vec_IntFree( vPairs );
+    // if parameters are not given, create them
+    if ( pPars == NULL )
+        Ssw_ManSetDefaultParams( pPars = &Pars );
+    // start the induction manager
+    p = Ssw_ManCreate( pMiter, pPars );
+    // create equivalence classes using these IDs
+    p->ppClasses = Ssw_ClassesPreparePairs( pMiter, pvClasses );
+    p->pSml = Ssw_SmlStart( pMiter, 0, p->nFrames + p->pPars->nFramesAddSim, 1 );
+    Ssw_ClassesSetData( p->ppClasses, p->pSml, Ssw_SmlObjHashWord, Ssw_SmlObjIsConstWord, Ssw_SmlObjsAreEqualWord );
+    // perform refinement of classes
+    pAigNew = Ssw_SignalCorrespondenceRefine( p );
+    // cleanup
+    Ssw_FreeTempClasses( pvClasses, Aig_ManObjNumMax(pMiter) );
+    Ssw_ManStop( p );
+    Aig_ManStop( pMiter );
+    return pAigNew;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Runs inductive SEC for the miter of two AIGs with node pairs defined.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Aig_Man_t * Ssw_SignalCorrespondeceTestPairs( Aig_Man_t * pAig )
+{
+    Aig_Man_t * pAigNew, * pAigRes;
+    Ssw_Pars_t Pars, * pPars = &Pars;
+    Vec_Int_t * vIds1, * vIds2;
+    Aig_Obj_t * pObj, * pRepr;
+    int RetValue, i, clk = clock();
+    Ssw_ManSetDefaultParams( pPars );
+    pPars->fVerbose = 1;
+    pAigNew = Ssw_SignalCorrespondence( pAig, pPars );
+    // record pairs of equivalent nodes
+    vIds1 = Vec_IntAlloc( Aig_ManObjNumMax(pAig) );
+    vIds2 = Vec_IntAlloc( Aig_ManObjNumMax(pAig) );
+    Aig_ManForEachObj( pAig, pObj, i )
+    {
+        pRepr = Aig_Regular(pObj->pData);
+        if ( pRepr == NULL )
+            continue;
+        if ( Aig_ManObj(pAigNew, pRepr->Id) == NULL )
+            continue;
+/*
+        if ( Aig_ObjIsNode(pObj) )
+            printf( "n " );
+        else if ( Saig_ObjIsPi(pAig, pObj) )
+            printf( "pi " );
+        else if ( Saig_ObjIsLo(pAig, pObj) )
+            printf( "lo " );
+*/
+        Vec_IntPush( vIds1, Aig_ObjId(pObj) );
+        Vec_IntPush( vIds2, Aig_ObjId(pRepr) );
+    }
+    printf( "Recorded %d pairs (before: %d  after: %d).\n", Vec_IntSize(vIds1), Aig_ManObjNumMax(pAig), Aig_ManObjNumMax(pAigNew) );
+    // try the new AIGs
+    pAigRes = Ssw_SignalCorrespondenceWithPairs( pAig, pAigNew, vIds1, vIds2, pPars );
+    Vec_IntFree( vIds1 );
+    Vec_IntFree( vIds2 );
+    // report the results
+    RetValue = Ssw_MiterStatus( pAigRes, 1 );
+    if ( RetValue == 1 )
+        printf( "Verification successful.  " );
+    else if ( RetValue == 0 )
+        printf( "Verification failed with the counter-example.  " );
+    else
+        printf( "Verification UNDECIDED. Remaining registers %d (total %d).  ", 
+            Aig_ManRegNum(pAigRes), Aig_ManRegNum(pAig) + Aig_ManRegNum(pAigNew) );
+    PRT( "Time", clock() - clk );
+    // cleanup
+    Aig_ManStop( pAigNew );
+    return pAigRes;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Runs inductive SEC for the miter of two AIGs with node pairs defined.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Ssw_SecWithPairs( Aig_Man_t * pAig1, Aig_Man_t * pAig2, Vec_Int_t * vIds1, Vec_Int_t * vIds2, Ssw_Pars_t * pPars )
+{
+    Aig_Man_t * pAigRes;
+    int RetValue, clk = clock();
+    assert( vIds1 != NULL && vIds2 != NULL );
+    // try the new AIGs
+    printf( "Performing specialized verification with node pairs.\n" );
+    pAigRes = Ssw_SignalCorrespondenceWithPairs( pAig1, pAig2, vIds1, vIds2, pPars );
+    // report the results
+    RetValue = Ssw_MiterStatus( pAigRes, 1 );
+    if ( RetValue == 1 )
+        printf( "Verification successful.  " );
+    else if ( RetValue == 0 )
+        printf( "Verification failed with a counter-example.  " );
+    else
+        printf( "Verification UNDECIDED. The number of remaining regs = %d (total = %d).  ", 
+            Aig_ManRegNum(pAigRes), Aig_ManRegNum(pAig1) + Aig_ManRegNum(pAig2) );
+    PRT( "Time", clock() - clk );
+    // cleanup
+    Aig_ManStop( pAigRes );
+    return RetValue;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Runs inductive SEC for the miter of two AIGs.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Ssw_SecGeneral( Aig_Man_t * pAig1, Aig_Man_t * pAig2, Ssw_Pars_t * pPars )
+{
+    Aig_Man_t * pAigRes, * pMiter;
+    int RetValue, clk = clock();
+    // try the new AIGs
+    printf( "Performing general verification without node pairs.\n" );
+    pMiter = Saig_ManCreateMiter( pAig1, pAig2, 0 );
+    pAigRes = Ssw_SignalCorrespondence( pMiter, pPars );
+    Aig_ManStop( pMiter );
+    // report the results
+    RetValue = Ssw_MiterStatus( pAigRes, 1 );
+    if ( RetValue == 1 )
+        printf( "Verification successful.  " );
+    else if ( RetValue == 0 )
+        printf( "Verification failed with a counter-example.  " );
+    else
+        printf( "Verification UNDECIDED. The number of remaining regs = %d (total = %d).  ", 
+            Aig_ManRegNum(pAigRes), Aig_ManRegNum(pAig1) + Aig_ManRegNum(pAig2) );
+    PRT( "Time", clock() - clk );
+    // cleanup
+    Aig_ManStop( pAigRes );
+    return RetValue;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Runs inductive SEC for the miter of two AIGs.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Ssw_SecGeneralMiter( Aig_Man_t * pMiter, Ssw_Pars_t * pPars )
+{
+    Aig_Man_t * pAigRes;
+    int RetValue, clk = clock();
+    // try the new AIGs
+//    printf( "Performing general verification without node pairs.\n" );
+    pAigRes = Ssw_SignalCorrespondence( pMiter, pPars );
+    // report the results
+    RetValue = Ssw_MiterStatus( pAigRes, 1 );
+    if ( RetValue == 1 )
+        printf( "Verification successful.  " );
+    else if ( RetValue == 0 )
+        printf( "Verification failed with a counter-example.  " );
+    else
+        printf( "Verification UNDECIDED. The number of remaining regs = %d (total = %d).  ", 
+            Aig_ManRegNum(pAigRes), Aig_ManRegNum(pMiter) );
+    PRT( "Time", clock() - clk );
+    // cleanup
+    Aig_ManStop( pAigRes );
+    return RetValue;
+}
+
+////////////////////////////////////////////////////////////////////////
+///                       END OF FILE                                ///
+////////////////////////////////////////////////////////////////////////
+
+
diff --git a/src/aig/ssw_old/sswPart.c b/src/aig/ssw_old/sswPart.c
new file mode 100644
index 00000000..7eb6b8fe
--- /dev/null
+++ b/src/aig/ssw_old/sswPart.c
@@ -0,0 +1,129 @@
+/**CFile****************************************************************
+
+  FileName    [sswPart.c]
+
+  SystemName  [ABC: Logic synthesis and verification system.]
+
+  PackageName [Inductive prover with constraints.]
+
+  Synopsis    [Partitioned signal correspondence.]
+
+  Author      [Alan Mishchenko]
+  
+  Affiliation [UC Berkeley]
+
+  Date        [Ver. 1.0. Started - September 1, 2008.]
+
+  Revision    [$Id: sswPart.c,v 1.00 2008/09/01 00:00:00 alanmi Exp $]
+
+***********************************************************************/
+
+#include "sswInt.h"
+
+////////////////////////////////////////////////////////////////////////
+///                        DECLARATIONS                              ///
+////////////////////////////////////////////////////////////////////////
+
+////////////////////////////////////////////////////////////////////////
+///                     FUNCTION DEFINITIONS                         ///
+////////////////////////////////////////////////////////////////////////
+
+/**Function*************************************************************
+
+  Synopsis    [Performs partitioned sequential SAT sweepingG.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Aig_Man_t * Ssw_SignalCorrespondencePart( Aig_Man_t * pAig, Ssw_Pars_t * pPars )
+{
+    int fPrintParts = 0;
+    char Buffer[100];
+    Aig_Man_t * pTemp, * pNew;
+    Vec_Ptr_t * vResult;
+    Vec_Int_t * vPart;
+    int * pMapBack;
+    int i, nCountPis, nCountRegs;
+    int nClasses, nPartSize, fVerbose;
+    int clk = clock();
+
+    // save parameters
+    nPartSize = pPars->nPartSize; pPars->nPartSize = 0;
+    fVerbose  = pPars->fVerbose;  pPars->fVerbose = 0;
+    // generate partitions
+    if ( pAig->vClockDoms )
+    {
+        // divide large clock domains into separate partitions
+        vResult = Vec_PtrAlloc( 100 );
+        Vec_PtrForEachEntry( (Vec_Ptr_t *)pAig->vClockDoms, vPart, i )
+        {
+            if ( nPartSize && Vec_IntSize(vPart) > nPartSize )
+                Aig_ManPartDivide( vResult, vPart, nPartSize, pPars->nOverSize );
+            else
+                Vec_PtrPush( vResult, Vec_IntDup(vPart) );
+        }
+    }
+    else
+        vResult = Aig_ManRegPartitionSimple( pAig, nPartSize, pPars->nOverSize );
+//    vResult = Aig_ManPartitionSmartRegisters( pAig, nPartSize, 0 ); 
+//    vResult = Aig_ManRegPartitionSmart( pAig, nPartSize );
+    if ( fPrintParts )
+    {
+        // print partitions
+        printf( "Simple partitioning. %d partitions are saved:\n", Vec_PtrSize(vResult) );
+        Vec_PtrForEachEntry( vResult, vPart, i )
+        {
+            extern void Ioa_WriteAiger( Aig_Man_t * pMan, char * pFileName, int fWriteSymbols, int fCompact );
+            sprintf( Buffer, "part%03d.aig", i );
+            pTemp = Aig_ManRegCreatePart( pAig, vPart, &nCountPis, &nCountRegs, NULL );
+            Ioa_WriteAiger( pTemp, Buffer, 0, 0 );
+            printf( "part%03d.aig : Reg = %4d. PI = %4d. (True = %4d. Regs = %4d.) And = %5d.\n", 
+                i, Vec_IntSize(vPart), Aig_ManPiNum(pTemp)-Vec_IntSize(vPart), nCountPis, nCountRegs, Aig_ManNodeNum(pTemp) );
+            Aig_ManStop( pTemp );
+        }
+    }
+
+    // perform SSW with partitions
+    Aig_ManReprStart( pAig, Aig_ManObjNumMax(pAig) );
+    Vec_PtrForEachEntry( vResult, vPart, i )
+    {
+        pTemp = Aig_ManRegCreatePart( pAig, vPart, &nCountPis, &nCountRegs, &pMapBack );
+        Aig_ManSetRegNum( pTemp, pTemp->nRegs );
+        // create the projection of 1-hot registers
+        if ( pAig->vOnehots )
+            pTemp->vOnehots = Aig_ManRegProjectOnehots( pAig, pTemp, pAig->vOnehots, fVerbose );
+        // run SSW
+        pNew = Ssw_SignalCorrespondence( pTemp, pPars );
+        nClasses = Aig_TransferMappedClasses( pAig, pTemp, pMapBack );
+        if ( fVerbose )
+            printf( "%3d : Reg = %4d. PI = %4d. (True = %4d. Regs = %4d.) And = %5d. It = %3d. Cl = %5d.\n", 
+                i, Vec_IntSize(vPart), Aig_ManPiNum(pTemp)-Vec_IntSize(vPart), nCountPis, nCountRegs, Aig_ManNodeNum(pTemp), pPars->nIters, nClasses );
+        Aig_ManStop( pNew );
+        Aig_ManStop( pTemp );
+        free( pMapBack );
+    }
+    // remap the AIG
+    pNew = Aig_ManDupRepr( pAig, 0 );
+    Aig_ManSeqCleanup( pNew );
+//    Aig_ManPrintStats( pAig );
+//    Aig_ManPrintStats( pNew );
+    Vec_VecFree( (Vec_Vec_t *)vResult );
+    pPars->nPartSize = nPartSize;
+    pPars->fVerbose = fVerbose;
+    if ( fVerbose )
+    {
+        PRT( "Total time", clock() - clk );
+    }
+    return pNew;
+}
+
+
+////////////////////////////////////////////////////////////////////////
+///                       END OF FILE                                ///
+////////////////////////////////////////////////////////////////////////
+
+
diff --git a/src/aig/ssw_old/sswSat.c b/src/aig/ssw_old/sswSat.c
new file mode 100644
index 00000000..85d3b8c1
--- /dev/null
+++ b/src/aig/ssw_old/sswSat.c
@@ -0,0 +1,264 @@
+/**CFile****************************************************************
+
+  FileName    [sswSat.c]
+
+  SystemName  [ABC: Logic synthesis and verification system.]
+
+  PackageName [Inductive prover with constraints.]
+
+  Synopsis    [Calls to the SAT solver.]
+
+  Author      [Alan Mishchenko]
+  
+  Affiliation [UC Berkeley]
+
+  Date        [Ver. 1.0. Started - September 1, 2008.]
+
+  Revision    [$Id: sswSat.c,v 1.00 2008/09/01 00:00:00 alanmi Exp $]
+
+***********************************************************************/
+
+#include "sswInt.h"
+
+////////////////////////////////////////////////////////////////////////
+///                        DECLARATIONS                              ///
+////////////////////////////////////////////////////////////////////////
+
+////////////////////////////////////////////////////////////////////////
+///                     FUNCTION DEFINITIONS                         ///
+////////////////////////////////////////////////////////////////////////
+
+/**Function*************************************************************
+
+  Synopsis    [Runs equivalence test for the two nodes.]
+
+  Description [Both nodes should be regular and different from each other.]
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Ssw_NodesAreEquiv( Ssw_Man_t * p, Aig_Obj_t * pOld, Aig_Obj_t * pNew )
+{
+    int nBTLimit = p->pPars->nBTLimit;
+    int pLits[3], nLits, RetValue, RetValue1, clk;//, status;
+    p->nSatCalls++;
+
+    // sanity checks
+    assert( !Aig_IsComplement(pOld) );
+    assert( !Aig_IsComplement(pNew) );
+    assert( pOld != pNew );
+
+    if ( p->pSat == NULL )
+        Ssw_ManStartSolver( p );
+
+    // if the nodes do not have SAT variables, allocate them
+    Ssw_CnfNodeAddToSolver( p, pOld );
+    Ssw_CnfNodeAddToSolver( p, pNew );
+
+    if ( p->pSat->qtail != p->pSat->qhead )
+    {
+        RetValue = sat_solver_simplify(p->pSat);
+        assert( RetValue != 0 );
+    }
+
+    // solve under assumptions
+    // A = 1; B = 0     OR     A = 1; B = 1 
+    nLits = 2;
+    pLits[0] = toLitCond( Ssw_ObjSatNum(p,pOld), 0 );
+    pLits[1] = toLitCond( Ssw_ObjSatNum(p,pNew), pOld->fPhase == pNew->fPhase );
+    if ( p->iOutputLit > -1 )
+        pLits[nLits++] = p->iOutputLit;
+    if ( p->pPars->fPolarFlip )
+    {
+        if ( pOld->fPhase )  pLits[0] = lit_neg( pLits[0] );
+        if ( pNew->fPhase )  pLits[1] = lit_neg( pLits[1] );
+    }
+//Sat_SolverWriteDimacs( p->pSat, "temp.cnf", pLits, pLits + 2, 1 );
+
+clk = clock();
+    RetValue1 = sat_solver_solve( p->pSat, pLits, pLits + nLits, 
+        (sint64)nBTLimit, (sint64)0, (sint64)0, (sint64)0 );
+p->timeSat += clock() - clk;
+    if ( RetValue1 == l_False )
+    {
+p->timeSatUnsat += clock() - clk;
+        if ( nLits == 2 )
+        {
+            pLits[0] = lit_neg( pLits[0] );
+            pLits[1] = lit_neg( pLits[1] );
+            RetValue = sat_solver_addclause( p->pSat, pLits, pLits + 2 );
+            assert( RetValue );
+        }
+        p->nSatCallsUnsat++;
+    }
+    else if ( RetValue1 == l_True )
+    {
+p->timeSatSat += clock() - clk;
+        p->nSatCallsSat++;
+        return 0;
+    }
+    else // if ( RetValue1 == l_Undef )
+    {
+p->timeSatUndec += clock() - clk;
+        p->nSatFailsReal++;
+        return -1;
+    }
+
+    // if the old node was constant 0, we already know the answer
+    if ( pOld == Aig_ManConst1(p->pFrames) )
+    {
+        p->nSatProof++;
+        return 1;
+    }
+
+    // solve under assumptions
+    // A = 0; B = 1     OR     A = 0; B = 0 
+    nLits = 2;
+    pLits[0] = toLitCond( Ssw_ObjSatNum(p,pOld), 1 );
+    pLits[1] = toLitCond( Ssw_ObjSatNum(p,pNew), pOld->fPhase ^ pNew->fPhase );
+    if ( p->iOutputLit > -1 )
+        pLits[nLits++] = p->iOutputLit;
+    if ( p->pPars->fPolarFlip )
+    {
+        if ( pOld->fPhase )  pLits[0] = lit_neg( pLits[0] );
+        if ( pNew->fPhase )  pLits[1] = lit_neg( pLits[1] );
+    }
+/*
+    if ( p->pSat->qtail != p->pSat->qhead )
+    {
+        RetValue = sat_solver_simplify(p->pSat);
+        assert( RetValue != 0 );
+    }
+*/
+clk = clock();
+    RetValue1 = sat_solver_solve( p->pSat, pLits, pLits + nLits, 
+        (sint64)nBTLimit, (sint64)0, (sint64)0, (sint64)0 );
+p->timeSat += clock() - clk;
+    if ( RetValue1 == l_False )
+    {
+p->timeSatUnsat += clock() - clk;
+        if ( nLits == 2 )
+        {
+            pLits[0] = lit_neg( pLits[0] );
+            pLits[1] = lit_neg( pLits[1] );
+            RetValue = sat_solver_addclause( p->pSat, pLits, pLits + 2 );
+            assert( RetValue );
+        }
+        p->nSatCallsUnsat++;
+    }
+    else if ( RetValue1 == l_True )
+    {
+p->timeSatSat += clock() - clk;
+        p->nSatCallsSat++;
+        return 0;
+    }
+    else // if ( RetValue1 == l_Undef )
+    {
+p->timeSatUndec += clock() - clk;
+        p->nSatFailsReal++;
+        return -1;
+    }
+    // return SAT proof
+    p->nSatProof++;
+    return 1;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Constrains two nodes to be equivalent in the SAT solver.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Ssw_NodesAreConstrained( Ssw_Man_t * p, Aig_Obj_t * pOld, Aig_Obj_t * pNew )
+{
+    int pLits[2], RetValue, fComplNew;
+    Aig_Obj_t * pTemp;
+
+    // sanity checks
+    assert( Aig_Regular(pOld) != Aig_Regular(pNew) );
+
+    // move constant to the old node
+    if ( Aig_Regular(pNew) == Aig_ManConst1(p->pFrames) )
+    {
+        assert( Aig_Regular(pOld) != Aig_ManConst1(p->pFrames) );
+        pTemp = pOld;
+        pOld  = pNew;
+        pNew  = pTemp;
+    }
+
+    // move complement to the new node
+    if ( Aig_IsComplement(pOld) )
+    {
+        pOld = Aig_Regular(pOld);
+        pNew = Aig_Not(pNew);
+    }
+
+    // start the solver
+    if ( p->pSat == NULL )
+        Ssw_ManStartSolver( p );
+
+    // if the nodes do not have SAT variables, allocate them
+    Ssw_CnfNodeAddToSolver( p, pOld );
+    Ssw_CnfNodeAddToSolver( p, Aig_Regular(pNew) );
+
+    // transform the new node
+    fComplNew = Aig_IsComplement( pNew );
+    pNew = Aig_Regular( pNew );
+
+    // consider the constant 1 case
+    if ( pOld == Aig_ManConst1(p->pFrames) )
+    {
+        // add constaint A = 1  ---->  A
+        pLits[0] = toLitCond( Ssw_ObjSatNum(p,pNew), fComplNew );
+        if ( p->pPars->fPolarFlip )
+        {
+            if ( pNew->fPhase )  pLits[0] = lit_neg( pLits[0] );
+        }
+        RetValue = sat_solver_addclause( p->pSat, pLits, pLits + 1 );
+        assert( RetValue );
+    }
+    else
+    {
+        // add constaint A = B  ---->  (A v !B)(!A v B)
+
+        // (A v !B)
+        pLits[0] = toLitCond( Ssw_ObjSatNum(p,pOld), 0 );
+        pLits[1] = toLitCond( Ssw_ObjSatNum(p,pNew), !fComplNew );
+        if ( p->pPars->fPolarFlip )
+        {
+            if ( pOld->fPhase )  pLits[0] = lit_neg( pLits[0] );
+            if ( pNew->fPhase )  pLits[1] = lit_neg( pLits[1] );
+        }
+        pLits[0] = lit_neg( pLits[0] );
+        pLits[1] = lit_neg( pLits[1] );
+        RetValue = sat_solver_addclause( p->pSat, pLits, pLits + 2 );
+        assert( RetValue );
+
+        // (!A v B)
+        pLits[0] = toLitCond( Ssw_ObjSatNum(p,pOld), 1 );
+        pLits[1] = toLitCond( Ssw_ObjSatNum(p,pNew), fComplNew);
+        if ( p->pPars->fPolarFlip )
+        {
+            if ( pOld->fPhase )  pLits[0] = lit_neg( pLits[0] );
+            if ( pNew->fPhase )  pLits[1] = lit_neg( pLits[1] );
+        }
+        pLits[0] = lit_neg( pLits[0] );
+        pLits[1] = lit_neg( pLits[1] );
+        RetValue = sat_solver_addclause( p->pSat, pLits, pLits + 2 );
+        assert( RetValue );
+    }
+    return 1;
+}
+
+////////////////////////////////////////////////////////////////////////
+///                       END OF FILE                                ///
+////////////////////////////////////////////////////////////////////////
+
+
diff --git a/src/aig/ssw_old/sswSim.c b/src/aig/ssw_old/sswSim.c
new file mode 100644
index 00000000..3fdb5cbc
--- /dev/null
+++ b/src/aig/ssw_old/sswSim.c
@@ -0,0 +1,1334 @@
+/**CFile****************************************************************
+
+  FileName    [sswSim.c]
+
+  SystemName  [ABC: Logic synthesis and verification system.]
+
+  PackageName [Inductive prover with constraints.]
+
+  Synopsis    [Sequential simulator used by the inductive prover.]
+
+  Author      [Alan Mishchenko]
+  
+  Affiliation [UC Berkeley]
+
+  Date        [Ver. 1.0. Started - September 1, 2008.]
+
+  Revision    [$Id: sswSim.c,v 1.00 2008/09/01 00:00:00 alanmi Exp $]
+
+***********************************************************************/
+
+#include "sswInt.h"
+
+////////////////////////////////////////////////////////////////////////
+///                        DECLARATIONS                              ///
+////////////////////////////////////////////////////////////////////////
+
+// simulation manager
+struct Ssw_Sml_t_
+{
+    Aig_Man_t *      pAig;              // the original AIG manager
+    int              nPref;             // the number of timeframes in the prefix
+    int              nFrames;           // the number of timeframes 
+    int              nWordsFrame;       // the number of words in each timeframe
+    int              nWordsTotal;       // the total number of words at a node
+    int              nWordsPref;        // the number of word in the prefix
+    int              fNonConstOut;      // have seen a non-const-0 output during simulation
+    int              nSimRounds;        // statistics
+    int              timeSim;           // statistics
+    unsigned         pData[0];          // simulation data for the nodes
+};
+
+static inline unsigned * Ssw_ObjSim( Ssw_Sml_t * p, int Id )  { return p->pData + p->nWordsTotal * Id; }
+static inline unsigned   Ssw_ObjRandomSim()                   { return Aig_ManRandom(0);               }
+
+////////////////////////////////////////////////////////////////////////
+///                     FUNCTION DEFINITIONS                         ///
+////////////////////////////////////////////////////////////////////////
+
+/**Function*************************************************************
+
+  Synopsis    [Computes hash value of the node using its simulation info.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+unsigned Ssw_SmlObjHashWord( Ssw_Sml_t * p, Aig_Obj_t * pObj )
+{
+    static int s_SPrimes[128] = { 
+        1009, 1049, 1093, 1151, 1201, 1249, 1297, 1361, 1427, 1459, 
+        1499, 1559, 1607, 1657, 1709, 1759, 1823, 1877, 1933, 1997, 
+        2039, 2089, 2141, 2213, 2269, 2311, 2371, 2411, 2467, 2543, 
+        2609, 2663, 2699, 2741, 2797, 2851, 2909, 2969, 3037, 3089, 
+        3169, 3221, 3299, 3331, 3389, 3461, 3517, 3557, 3613, 3671, 
+        3719, 3779, 3847, 3907, 3943, 4013, 4073, 4129, 4201, 4243, 
+        4289, 4363, 4441, 4493, 4549, 4621, 4663, 4729, 4793, 4871, 
+        4933, 4973, 5021, 5087, 5153, 5227, 5281, 5351, 5417, 5471, 
+        5519, 5573, 5651, 5693, 5749, 5821, 5861, 5923, 6011, 6073, 
+        6131, 6199, 6257, 6301, 6353, 6397, 6481, 6563, 6619, 6689, 
+        6737, 6803, 6863, 6917, 6977, 7027, 7109, 7187, 7237, 7309, 
+        7393, 7477, 7523, 7561, 7607, 7681, 7727, 7817, 7877, 7933, 
+        8011, 8039, 8059, 8081, 8093, 8111, 8123, 8147
+    };
+    unsigned * pSims;
+    unsigned uHash;
+    int i;
+    assert( p->nWordsTotal <= 128 );
+    uHash = 0;
+    pSims = Ssw_ObjSim(p, pObj->Id);
+    for ( i = p->nWordsPref; i < p->nWordsTotal; i++ )
+        uHash ^= pSims[i] * s_SPrimes[i & 0x7F];
+    return uHash;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Returns 1 if simulation info is composed of all zeros.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Ssw_SmlObjIsConstWord( Ssw_Sml_t * p, Aig_Obj_t * pObj )
+{
+    unsigned * pSims;
+    int i;
+    pSims = Ssw_ObjSim(p, pObj->Id);
+    for ( i = p->nWordsPref; i < p->nWordsTotal; i++ )
+        if ( pSims[i] )
+            return 0;
+    return 1;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Returns 1 if simulation infos are equal.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Ssw_SmlObjsAreEqualWord( Ssw_Sml_t * p, Aig_Obj_t * pObj0, Aig_Obj_t * pObj1 )
+{
+    unsigned * pSims0, * pSims1;
+    int i;
+    pSims0 = Ssw_ObjSim(p, pObj0->Id);
+    pSims1 = Ssw_ObjSim(p, pObj1->Id);
+    for ( i = p->nWordsPref; i < p->nWordsTotal; i++ )
+        if ( pSims0[i] != pSims1[i] )
+            return 0;
+    return 1;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Returns 1 if the node appears to be constant 1 candidate.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Ssw_SmlObjIsConstBit( void * p, Aig_Obj_t * pObj )
+{
+    return pObj->fPhase == pObj->fMarkB;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Returns 1 if the nodes appear equal.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Ssw_SmlObjsAreEqualBit( void * p, Aig_Obj_t * pObj0, Aig_Obj_t * pObj1 )
+{
+    return (pObj0->fPhase == pObj1->fPhase) == (pObj0->fMarkB == pObj1->fMarkB);
+}
+
+
+/**Function*************************************************************
+
+  Synopsis    [Counts the number of 1s in the XOR of simulation data.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Ssw_SmlNodeNotEquWeight( Ssw_Sml_t * p, int Left, int Right )
+{
+    unsigned * pSimL, * pSimR;
+    int k, Counter = 0;
+    pSimL = Ssw_ObjSim( p, Left );
+    pSimR = Ssw_ObjSim( p, Right );
+    for ( k = p->nWordsPref; k < p->nWordsTotal; k++ )
+        Counter += Aig_WordCountOnes( pSimL[k] ^ pSimR[k] );
+    return Counter;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Returns 1 if simulation info is composed of all zeros.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Ssw_SmlNodeIsZero( Ssw_Sml_t * p, Aig_Obj_t * pObj )
+{
+    unsigned * pSims;
+    int i;
+    pSims = Ssw_ObjSim(p, pObj->Id);
+    for ( i = p->nWordsPref; i < p->nWordsTotal; i++ )
+        if ( pSims[i] )
+            return 0;
+    return 1;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Counts the number of one's in the patten of the output.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Ssw_SmlNodeCountOnes( Ssw_Sml_t * p, Aig_Obj_t * pObj )
+{
+    unsigned * pSims;
+    int i, Counter = 0;
+    pSims = Ssw_ObjSim(p, pObj->Id);
+    for ( i = 0; i < p->nWordsTotal; i++ )
+        Counter += Aig_WordCountOnes( pSims[i] );
+    return Counter;
+}
+
+
+
+/**Function*************************************************************
+
+  Synopsis    [Generated const 0 pattern.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ssw_SmlSavePattern0( Ssw_Man_t * p, int fInit )
+{
+    memset( p->pPatWords, 0, sizeof(unsigned) * p->nPatWords );
+}
+
+/**Function*************************************************************
+
+  Synopsis    [[Generated const 1 pattern.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ssw_SmlSavePattern1( Ssw_Man_t * p, int fInit )
+{
+    Aig_Obj_t * pObj;
+    int i, k, nTruePis;
+    memset( p->pPatWords, 0xff, sizeof(unsigned) * p->nPatWords );
+    if ( !fInit )
+        return;
+    // clear the state bits to correspond to all-0 initial state
+    nTruePis = Saig_ManPiNum(p->pAig);
+    k = 0;
+    Saig_ManForEachLo( p->pAig, pObj, i )
+        Aig_InfoXorBit( p->pPatWords, nTruePis * p->nFrames + k++ );
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Copy pattern from the solver into the internal storage.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ssw_SmlSavePattern( Ssw_Man_t * p )
+{
+    Aig_Obj_t * pObj;
+    int i;
+    memset( p->pPatWords, 0, sizeof(unsigned) * p->nPatWords );
+    Aig_ManForEachPi( p->pFrames, pObj, i )
+        if ( p->pSat->model.ptr[Ssw_ObjSatNum(p, pObj)] == l_True )
+            Aig_InfoSetBit( p->pPatWords, i );
+/*
+    if ( p->vCex )
+    {
+        Vec_IntClear( p->vCex );
+        for ( i = 0; i < Saig_ManPiNum(p->pAig); i++ )
+            Vec_IntPush( p->vCex, Aig_InfoHasBit( p->pPatWords, i ) );
+        for ( i = Saig_ManPiNum(p->pFrames); i < Aig_ManPiNum(p->pFrames); i++ )
+            Vec_IntPush( p->vCex, Aig_InfoHasBit( p->pPatWords, i ) );
+    }
+*/
+
+/*
+    printf( "Pattern: " );
+    Aig_ManForEachPi( p->pFrames, pObj, i )
+        printf( "%d", Aig_InfoHasBit( p->pPatWords, i ) );
+    printf( "\n" );
+*/
+}
+
+
+
+/**Function*************************************************************
+
+  Synopsis    [Creates the counter-example from the successful pattern.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int * Ssw_SmlCheckOutputSavePattern( Ssw_Sml_t * p, Aig_Obj_t * pObjPo )
+{ 
+    Aig_Obj_t * pFanin, * pObjPi;
+    unsigned * pSims;
+    int i, k, BestPat, * pModel;
+    // find the word of the pattern
+    pFanin = Aig_ObjFanin0(pObjPo);
+    pSims = Ssw_ObjSim(p, pFanin->Id);
+    for ( i = 0; i < p->nWordsTotal; i++ )
+        if ( pSims[i] )
+            break;
+    assert( i < p->nWordsTotal );
+    // find the bit of the pattern
+    for ( k = 0; k < 32; k++ )
+        if ( pSims[i] & (1 << k) )
+            break;
+    assert( k < 32 );
+    // determine the best pattern
+    BestPat = i * 32 + k;
+    // fill in the counter-example data
+    pModel = ALLOC( int, Aig_ManPiNum(p->pAig)+1 );
+    Aig_ManForEachPi( p->pAig, pObjPi, i )
+    {
+        pModel[i] = Aig_InfoHasBit(Ssw_ObjSim(p, pObjPi->Id), BestPat);
+//        printf( "%d", pModel[i] );
+    }
+    pModel[Aig_ManPiNum(p->pAig)] = pObjPo->Id;
+//    printf( "\n" );
+    return pModel;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Returns 1 if the one of the output is already non-constant 0.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int * Ssw_SmlCheckOutput( Ssw_Sml_t * p )
+{
+    Aig_Obj_t * pObj;
+    int i;
+    // make sure the reference simulation pattern does not detect the bug
+    pObj = Aig_ManPo( p->pAig, 0 );
+    assert( Aig_ObjFanin0(pObj)->fPhase == (unsigned)Aig_ObjFaninC0(pObj) ); 
+    Aig_ManForEachPo( p->pAig, pObj, i )
+    {
+        if ( !Ssw_SmlObjIsConstWord( p, Aig_ObjFanin0(pObj) ) )
+        {
+            // create the counter-example from this pattern
+            return Ssw_SmlCheckOutputSavePattern( p, pObj );
+        }
+    }
+    return NULL;
+}
+
+
+
+/**Function*************************************************************
+
+  Synopsis    [Assigns random patterns to the PI node.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ssw_SmlAssignRandom( Ssw_Sml_t * p, Aig_Obj_t * pObj )
+{
+    unsigned * pSims;
+    int i;
+    assert( Aig_ObjIsPi(pObj) );
+    pSims = Ssw_ObjSim( p, pObj->Id );
+    for ( i = 0; i < p->nWordsTotal; i++ )
+        pSims[i] = Ssw_ObjRandomSim();
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Assigns random patterns to the PI node.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ssw_SmlAssignRandomFrame( Ssw_Sml_t * p, Aig_Obj_t * pObj, int iFrame )
+{
+    unsigned * pSims;
+    int i;
+    assert( Aig_ObjIsPi(pObj) );
+    pSims = Ssw_ObjSim( p, pObj->Id ) + p->nWordsFrame * iFrame;
+    for ( i = 0; i < p->nWordsFrame; i++ )
+        pSims[i] = Ssw_ObjRandomSim();
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Assigns constant patterns to the PI node.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ssw_SmlObjAssignConst( Ssw_Sml_t * p, Aig_Obj_t * pObj, int fConst1, int iFrame )
+{
+    unsigned * pSims;
+    int i;
+    assert( Aig_ObjIsPi(pObj) );
+    pSims = Ssw_ObjSim( p, pObj->Id ) + p->nWordsFrame * iFrame;
+    for ( i = 0; i < p->nWordsFrame; i++ )
+        pSims[i] = fConst1? ~(unsigned)0 : 0;
+} 
+
+/**Function*************************************************************
+
+  Synopsis    [Assigns constant patterns to the PI node.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+unsigned Ssw_SmlObjGetWord( Ssw_Sml_t * p, Aig_Obj_t * pObj, int iWord, int iFrame )
+{
+    unsigned * pSims;
+//    assert( Aig_ObjIsPi(pObj) );
+    pSims = Ssw_ObjSim( p, pObj->Id ) + p->nWordsFrame * iFrame;
+    return pSims[iWord];
+} 
+
+/**Function*************************************************************
+
+  Synopsis    [Assigns constant patterns to the PI node.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ssw_SmlObjSetWord( Ssw_Sml_t * p, Aig_Obj_t * pObj, unsigned Word, int iWord, int iFrame )
+{
+    unsigned * pSims;
+    assert( Aig_ObjIsPi(pObj) );
+    pSims = Ssw_ObjSim( p, pObj->Id ) + p->nWordsFrame * iFrame;
+    pSims[iWord] = Word;
+} 
+
+/**Function*************************************************************
+
+  Synopsis    [Assings random simulation info for the PIs.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ssw_SmlInitialize( Ssw_Sml_t * p, int fInit )
+{
+    Aig_Obj_t * pObj;
+    int i;
+    if ( fInit )
+    {
+        assert( Aig_ManRegNum(p->pAig) > 0 );
+        assert( Aig_ManRegNum(p->pAig) < Aig_ManPiNum(p->pAig) );
+        // assign random info for primary inputs
+        Saig_ManForEachPi( p->pAig, pObj, i )
+            Ssw_SmlAssignRandom( p, pObj );
+        // assign the initial state for the latches
+        Saig_ManForEachLo( p->pAig, pObj, i )
+            Ssw_SmlObjAssignConst( p, pObj, 0, 0 );
+    }
+    else
+    {
+        Aig_ManForEachPi( p->pAig, pObj, i )
+            Ssw_SmlAssignRandom( p, pObj );
+    }
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Assings distance-1 simulation info for the PIs.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ssw_SmlAssignDist1( Ssw_Sml_t * p, unsigned * pPat )
+{
+    Aig_Obj_t * pObj;
+    int f, i, k, Limit, nTruePis;
+    assert( p->nFrames > 0 );
+    if ( p->nFrames == 1 )
+    {
+        // copy the PI info 
+        Aig_ManForEachPi( p->pAig, pObj, i )
+            Ssw_SmlObjAssignConst( p, pObj, Aig_InfoHasBit(pPat, i), 0 );
+        // flip one bit
+        Limit = AIG_MIN( Aig_ManPiNum(p->pAig), p->nWordsTotal * 32 - 1 );
+        for ( i = 0; i < Limit; i++ )
+            Aig_InfoXorBit( Ssw_ObjSim( p, Aig_ManPi(p->pAig,i)->Id ), i+1 );
+    }
+    else
+    {
+        int fUseDist1 = 0;
+
+        // copy the PI info for each frame
+        nTruePis = Aig_ManPiNum(p->pAig) - Aig_ManRegNum(p->pAig);
+        for ( f = 0; f < p->nFrames; f++ )
+            Saig_ManForEachPi( p->pAig, pObj, i )
+                Ssw_SmlObjAssignConst( p, pObj, Aig_InfoHasBit(pPat, nTruePis * f + i), f );
+        // copy the latch info 
+        k = 0;
+        Saig_ManForEachLo( p->pAig, pObj, i )
+            Ssw_SmlObjAssignConst( p, pObj, Aig_InfoHasBit(pPat, nTruePis * p->nFrames + k++), 0 );
+//        assert( p->pFrames == NULL || nTruePis * p->nFrames + k == Aig_ManPiNum(p->pFrames) );
+
+        // flip one bit of the last frame
+        if ( fUseDist1 ) //&& p->nFrames == 2 )
+        {
+            Limit = AIG_MIN( nTruePis, p->nWordsFrame * 32 - 1 );
+            for ( i = 0; i < Limit; i++ )
+                Aig_InfoXorBit( Ssw_ObjSim( p, Aig_ManPi(p->pAig, i)->Id ) + p->nWordsFrame*(p->nFrames-1), i+1 );
+        }
+    }
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Assings distance-1 simulation info for the PIs.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ssw_SmlAssignDist1Plus( Ssw_Sml_t * p, unsigned * pPat )
+{
+    Aig_Obj_t * pObj;
+    int f, i, Limit;
+    assert( p->nFrames > 0 );
+
+    // copy the pattern into the primary inputs
+    Aig_ManForEachPi( p->pAig, pObj, i )
+        Ssw_SmlObjAssignConst( p, pObj, Aig_InfoHasBit(pPat, i), 0 );
+/*
+    // set distance one PIs for the first frame
+    Limit = AIG_MIN( Saig_ManPiNum(p->pAig), p->nWordsFrame * 32 - 1 );
+    for ( i = 0; i < Limit; i++ )
+        Aig_InfoXorBit( Ssw_ObjSim( p, Aig_ManPi(p->pAig, i)->Id ), i+1 );
+*/
+    // create random info for the remaining timeframes
+    for ( f = 1; f < p->nFrames; f++ )
+        Saig_ManForEachPi( p->pAig, pObj, i )
+            Ssw_SmlAssignRandomFrame( p, pObj, f );
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Simulates one node.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ssw_SmlNodeSimulate( Ssw_Sml_t * p, Aig_Obj_t * pObj, int iFrame )
+{
+    unsigned * pSims, * pSims0, * pSims1;
+    int fCompl, fCompl0, fCompl1, i;
+    assert( !Aig_IsComplement(pObj) );
+    assert( Aig_ObjIsNode(pObj) );
+    assert( iFrame == 0 || p->nWordsFrame < p->nWordsTotal );
+    // get hold of the simulation information
+    pSims  = Ssw_ObjSim(p, pObj->Id) + p->nWordsFrame * iFrame;
+    pSims0 = Ssw_ObjSim(p, Aig_ObjFanin0(pObj)->Id) + p->nWordsFrame * iFrame;
+    pSims1 = Ssw_ObjSim(p, Aig_ObjFanin1(pObj)->Id) + p->nWordsFrame * iFrame;
+    // get complemented attributes of the children using their random info
+    fCompl  = pObj->fPhase;
+    fCompl0 = Aig_ObjPhaseReal(Aig_ObjChild0(pObj));
+    fCompl1 = Aig_ObjPhaseReal(Aig_ObjChild1(pObj));
+    // simulate
+    if ( fCompl0 && fCompl1 )
+    {
+        if ( fCompl )
+            for ( i = 0; i < p->nWordsFrame; i++ )
+                pSims[i] = (pSims0[i] | pSims1[i]);
+        else
+            for ( i = 0; i < p->nWordsFrame; i++ )
+                pSims[i] = ~(pSims0[i] | pSims1[i]);
+    }
+    else if ( fCompl0 && !fCompl1 )
+    {
+        if ( fCompl )
+            for ( i = 0; i < p->nWordsFrame; i++ )
+                pSims[i] = (pSims0[i] | ~pSims1[i]);
+        else
+            for ( i = 0; i < p->nWordsFrame; i++ )
+                pSims[i] = (~pSims0[i] & pSims1[i]);
+    }
+    else if ( !fCompl0 && fCompl1 )
+    {
+        if ( fCompl )
+            for ( i = 0; i < p->nWordsFrame; i++ )
+                pSims[i] = (~pSims0[i] | pSims1[i]);
+        else
+            for ( i = 0; i < p->nWordsFrame; i++ )
+                pSims[i] = (pSims0[i] & ~pSims1[i]);
+    }
+    else // if ( !fCompl0 && !fCompl1 )
+    {
+        if ( fCompl )
+            for ( i = 0; i < p->nWordsFrame; i++ )
+                pSims[i] = ~(pSims0[i] & pSims1[i]);
+        else
+            for ( i = 0; i < p->nWordsFrame; i++ )
+                pSims[i] = (pSims0[i] & pSims1[i]);
+    }
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Simulates one node.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Ssw_SmlNodesCompareInFrame( Ssw_Sml_t * p, Aig_Obj_t * pObj0, Aig_Obj_t * pObj1, int iFrame0, int iFrame1 )
+{
+    unsigned * pSims0, * pSims1;
+    int i;
+    assert( !Aig_IsComplement(pObj0) );
+    assert( !Aig_IsComplement(pObj1) );
+    assert( iFrame0 == 0 || p->nWordsFrame < p->nWordsTotal );
+    assert( iFrame1 == 0 || p->nWordsFrame < p->nWordsTotal );
+    // get hold of the simulation information
+    pSims0  = Ssw_ObjSim(p, pObj0->Id) + p->nWordsFrame * iFrame0;
+    pSims1  = Ssw_ObjSim(p, pObj1->Id) + p->nWordsFrame * iFrame1;
+    // compare
+    for ( i = 0; i < p->nWordsFrame; i++ )
+        if ( pSims0[i] != pSims1[i] )
+            return 0;
+    return 1;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Simulates one node.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ssw_SmlNodeCopyFanin( Ssw_Sml_t * p, Aig_Obj_t * pObj, int iFrame )
+{
+    unsigned * pSims, * pSims0;
+    int fCompl, fCompl0, i;
+    assert( !Aig_IsComplement(pObj) );
+    assert( Aig_ObjIsPo(pObj) );
+    assert( iFrame == 0 || p->nWordsFrame < p->nWordsTotal );
+    // get hold of the simulation information
+    pSims  = Ssw_ObjSim(p, pObj->Id) + p->nWordsFrame * iFrame;
+    pSims0 = Ssw_ObjSim(p, Aig_ObjFanin0(pObj)->Id) + p->nWordsFrame * iFrame;
+    // get complemented attributes of the children using their random info
+    fCompl  = pObj->fPhase;
+    fCompl0 = Aig_ObjPhaseReal(Aig_ObjChild0(pObj));
+    // copy information as it is
+    if ( fCompl0 )
+        for ( i = 0; i < p->nWordsFrame; i++ )
+            pSims[i] = ~pSims0[i];
+    else
+        for ( i = 0; i < p->nWordsFrame; i++ )
+            pSims[i] = pSims0[i];
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Simulates one node.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ssw_SmlNodeTransferNext( Ssw_Sml_t * p, Aig_Obj_t * pOut, Aig_Obj_t * pIn, int iFrame )
+{
+    unsigned * pSims0, * pSims1;
+    int i;
+    assert( !Aig_IsComplement(pOut) );
+    assert( !Aig_IsComplement(pIn) );
+    assert( Aig_ObjIsPo(pOut) );
+    assert( Aig_ObjIsPi(pIn) );
+    assert( iFrame == 0 || p->nWordsFrame < p->nWordsTotal );
+    // get hold of the simulation information
+    pSims0 = Ssw_ObjSim(p, pOut->Id) + p->nWordsFrame * iFrame;
+    pSims1 = Ssw_ObjSim(p, pIn->Id) + p->nWordsFrame * (iFrame+1);
+    // copy information as it is
+    for ( i = 0; i < p->nWordsFrame; i++ )
+        pSims1[i] = pSims0[i];
+}
+
+
+/**Function*************************************************************
+
+  Synopsis    [Check if any of the POs becomes non-constant.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Ssw_SmlCheckNonConstOutputs( Ssw_Sml_t * p )
+{
+    Aig_Obj_t * pObj;
+    int i;
+    Saig_ManForEachPo( p->pAig, pObj, i )
+        if ( !Ssw_SmlNodeIsZero(p, pObj) )
+            return 1;
+    return 0;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Simulates AIG manager.]
+
+  Description [Assumes that the PI simulation info is attached.]
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ssw_SmlSimulateOne( Ssw_Sml_t * p )
+{
+    Aig_Obj_t * pObj, * pObjLi, * pObjLo;
+    int f, i, clk;
+clk = clock();
+    for ( f = 0; f < p->nFrames; f++ )
+    {
+        // simulate the nodes
+        Aig_ManForEachNode( p->pAig, pObj, i )
+            Ssw_SmlNodeSimulate( p, pObj, f );
+        // copy simulation info into outputs
+        Saig_ManForEachPo( p->pAig, pObj, i )
+            Ssw_SmlNodeCopyFanin( p, pObj, f );
+        // quit if this is the last timeframe
+        if ( f == p->nFrames - 1 )
+            break;
+        // copy simulation info into outputs
+        Saig_ManForEachLi( p->pAig, pObj, i )
+            Ssw_SmlNodeCopyFanin( p, pObj, f );
+        // copy simulation info into the inputs
+        Saig_ManForEachLiLo( p->pAig, pObjLi, pObjLo, i )
+            Ssw_SmlNodeTransferNext( p, pObjLi, pObjLo, f );
+    }
+p->timeSim += clock() - clk;
+p->nSimRounds++;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Simulates AIG manager.]
+
+  Description [Assumes that the PI simulation info is attached.]
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ssw_SmlSimulateOneFrame( Ssw_Sml_t * p )
+{
+    Aig_Obj_t * pObj, * pObjLi, * pObjLo;
+    int i, clk;
+clk = clock();
+    // simulate the nodes
+    Aig_ManForEachNode( p->pAig, pObj, i )
+        Ssw_SmlNodeSimulate( p, pObj, 0 );
+    // copy simulation info into outputs
+    Saig_ManForEachLi( p->pAig, pObj, i )
+        Ssw_SmlNodeCopyFanin( p, pObj, 0 );
+    // copy simulation info into the inputs
+    Saig_ManForEachLiLo( p->pAig, pObjLi, pObjLo, i )
+        Ssw_SmlNodeTransferNext( p, pObjLi, pObjLo, 0 );
+p->timeSim += clock() - clk;
+p->nSimRounds++;
+}
+
+
+/**Function*************************************************************
+
+  Synopsis    [Allocates simulation manager.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Ssw_Sml_t * Ssw_SmlStart( Aig_Man_t * pAig, int nPref, int nFrames, int nWordsFrame )
+{
+    Ssw_Sml_t * p;
+    p = (Ssw_Sml_t *)malloc( sizeof(Ssw_Sml_t) + sizeof(unsigned) * Aig_ManObjNumMax(pAig) * (nPref + nFrames) * nWordsFrame );
+    memset( p, 0, sizeof(Ssw_Sml_t) + sizeof(unsigned) * (nPref + nFrames) * nWordsFrame );
+    p->pAig        = pAig;
+    p->nPref       = nPref;
+    p->nFrames     = nPref + nFrames;
+    p->nWordsFrame = nWordsFrame;
+    p->nWordsTotal = (nPref + nFrames) * nWordsFrame;
+    p->nWordsPref  = nPref * nWordsFrame;
+    return p;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Allocates simulation manager.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ssw_SmlClean( Ssw_Sml_t * p )
+{
+    memset( p->pData, 0, sizeof(unsigned) * Aig_ManObjNumMax(p->pAig) * p->nWordsTotal );
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Deallocates simulation manager.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ssw_SmlStop( Ssw_Sml_t * p )
+{
+    free( p );
+}
+
+
+/**Function*************************************************************
+
+  Synopsis    [Performs simulation of the uninitialized circuit.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Ssw_Sml_t * Ssw_SmlSimulateComb( Aig_Man_t * pAig, int nWords )
+{
+    Ssw_Sml_t * p;
+    p = Ssw_SmlStart( pAig, 0, 1, nWords );
+    Ssw_SmlInitialize( p, 0 );
+    Ssw_SmlSimulateOne( p );
+    return p;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Performs simulation of the initialized circuit.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Ssw_Sml_t * Ssw_SmlSimulateSeq( Aig_Man_t * pAig, int nPref, int nFrames, int nWords )
+{
+    Ssw_Sml_t * p;
+    p = Ssw_SmlStart( pAig, nPref, nFrames, nWords );
+    Ssw_SmlInitialize( p, 1 );
+    Ssw_SmlSimulateOne( p );
+    p->fNonConstOut = Ssw_SmlCheckNonConstOutputs( p );
+    return p;
+}
+
+
+
+/**Function*************************************************************
+
+  Synopsis    [Allocates a counter-example.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Ssw_Cex_t * Ssw_SmlAllocCounterExample( int nRegs, int nRealPis, int nFrames )
+{
+    Ssw_Cex_t * pCex;
+    int nWords = Aig_BitWordNum( nRegs + nRealPis * nFrames );
+    pCex = (Ssw_Cex_t *)malloc( sizeof(Ssw_Cex_t) + sizeof(unsigned) * nWords );
+    memset( pCex, 0, sizeof(Ssw_Cex_t) + sizeof(unsigned) * nWords );
+    pCex->nRegs  = nRegs;
+    pCex->nPis   = nRealPis;
+    pCex->nBits  = nRegs + nRealPis * nFrames;
+    return pCex;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Frees the counter-example.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ssw_SmlFreeCounterExample( Ssw_Cex_t * pCex )
+{
+    free( pCex );
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Resimulates the counter-example.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Ssw_SmlRunCounterExample( Aig_Man_t * pAig, Ssw_Cex_t * p )
+{
+    Ssw_Sml_t * pSml;
+    Aig_Obj_t * pObj;
+    int RetValue, i, k, iBit;
+    assert( Aig_ManRegNum(pAig) > 0 );
+    assert( Aig_ManRegNum(pAig) < Aig_ManPiNum(pAig) );
+    // start a new sequential simulator
+    pSml = Ssw_SmlStart( pAig, 0, p->iFrame+1, 1 );
+    // assign simulation info for the registers
+    iBit = 0;
+    Saig_ManForEachLo( pAig, pObj, i )
+        Ssw_SmlObjAssignConst( pSml, pObj, Aig_InfoHasBit(p->pData, iBit++), 0 );
+    // assign simulation info for the primary inputs
+    for ( i = 0; i <= p->iFrame; i++ )
+        Saig_ManForEachPi( pAig, pObj, k )
+            Ssw_SmlObjAssignConst( pSml, pObj, Aig_InfoHasBit(p->pData, iBit++), i );
+    assert( iBit == p->nBits );
+    // run random simulation
+    Ssw_SmlSimulateOne( pSml );
+    // check if the given output has failed
+    RetValue = !Ssw_SmlNodeIsZero( pSml, Aig_ManPo(pAig, p->iPo) );
+    Ssw_SmlStop( pSml );
+    return RetValue;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Resimulates the counter-example.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Ssw_SmlFindOutputCounterExample( Aig_Man_t * pAig, Ssw_Cex_t * p )
+{
+    Ssw_Sml_t * pSml;
+    Aig_Obj_t * pObj;
+    int i, k, iBit, iOut;
+    assert( Aig_ManRegNum(pAig) > 0 );
+    assert( Aig_ManRegNum(pAig) < Aig_ManPiNum(pAig) );
+    // start a new sequential simulator
+    pSml = Ssw_SmlStart( pAig, 0, p->iFrame+1, 1 );
+    // assign simulation info for the registers
+    iBit = 0;
+    Saig_ManForEachLo( pAig, pObj, i )
+        Ssw_SmlObjAssignConst( pSml, pObj, Aig_InfoHasBit(p->pData, iBit++), 0 );
+    // assign simulation info for the primary inputs
+    for ( i = 0; i <= p->iFrame; i++ )
+        Saig_ManForEachPi( pAig, pObj, k )
+            Ssw_SmlObjAssignConst( pSml, pObj, Aig_InfoHasBit(p->pData, iBit++), i );
+    assert( iBit == p->nBits );
+    // run random simulation
+    Ssw_SmlSimulateOne( pSml );
+    // check if the given output has failed
+    iOut = -1;
+    Saig_ManForEachPo( pAig, pObj, k )
+        if ( !Ssw_SmlNodeIsZero( pSml, Aig_ManPo(pAig, k) ) )
+        {
+            iOut = k;
+            break;
+        }
+    Ssw_SmlStop( pSml );
+    return iOut;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Creates sequential counter-example from the simulation info.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Ssw_Cex_t * Ssw_SmlGetCounterExample( Ssw_Sml_t * p )
+{
+    Ssw_Cex_t * pCex;
+    Aig_Obj_t * pObj;
+    unsigned * pSims;
+    int iPo, iFrame, iBit, i, k;
+
+    // make sure the simulation manager has it
+    assert( p->fNonConstOut );
+
+    // find the first output that failed
+    iPo = -1;
+    iBit = -1;
+    iFrame = -1;
+    Saig_ManForEachPo( p->pAig, pObj, iPo )
+    {
+        if ( Ssw_SmlNodeIsZero(p, pObj) )
+            continue;
+        pSims = Ssw_ObjSim( p, pObj->Id );
+        for ( i = p->nWordsPref; i < p->nWordsTotal; i++ )
+            if ( pSims[i] )
+            {
+                iFrame = i / p->nWordsFrame;
+                iBit = 32 * (i % p->nWordsFrame) + Aig_WordFindFirstBit( pSims[i] );
+                break;
+            }
+        break;
+    }
+    assert( iPo < Aig_ManPoNum(p->pAig)-Aig_ManRegNum(p->pAig) );
+    assert( iFrame < p->nFrames );
+    assert( iBit < 32 * p->nWordsFrame );
+
+    // allocate the counter example
+    pCex = Ssw_SmlAllocCounterExample( Aig_ManRegNum(p->pAig), Aig_ManPiNum(p->pAig) - Aig_ManRegNum(p->pAig), iFrame + 1 );
+    pCex->iPo    = iPo;
+    pCex->iFrame = iFrame;
+
+    // copy the bit data
+    Saig_ManForEachLo( p->pAig, pObj, k )
+    {
+        pSims = Ssw_ObjSim( p, pObj->Id );
+        if ( Aig_InfoHasBit( pSims, iBit ) )
+            Aig_InfoSetBit( pCex->pData, k );
+    }
+    for ( i = 0; i <= iFrame; i++ )
+    {
+        Saig_ManForEachPi( p->pAig, pObj, k )
+        {
+            pSims = Ssw_ObjSim( p, pObj->Id );
+            if ( Aig_InfoHasBit( pSims, 32 * p->nWordsFrame * i + iBit ) )
+                Aig_InfoSetBit( pCex->pData, pCex->nRegs + pCex->nPis * i + k );
+        }
+    }
+    // verify the counter example
+    if ( !Ssw_SmlRunCounterExample( p->pAig, pCex ) )
+    {
+        printf( "Ssw_SmlGetCounterExample(): Counter-example is invalid.\n" );
+        Ssw_SmlFreeCounterExample( pCex );
+        pCex = NULL;
+    }
+    return pCex;
+}
+ 
+/**Function*************************************************************
+
+  Synopsis    [Generates seq counter-example from the combinational one.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Ssw_Cex_t * Ssw_SmlCopyCounterExample( Aig_Man_t * pAig, Aig_Man_t * pFrames, int * pModel )
+{
+    Ssw_Cex_t * pCex;
+    Aig_Obj_t * pObj;
+    int i, nFrames, nTruePis, nTruePos, iPo, iFrame;
+    // get the number of frames
+    assert( Aig_ManRegNum(pAig) > 0 );
+    assert( Aig_ManRegNum(pFrames) == 0 );
+    nTruePis = Aig_ManPiNum(pAig)-Aig_ManRegNum(pAig);
+    nTruePos = Aig_ManPoNum(pAig)-Aig_ManRegNum(pAig);
+    nFrames = Aig_ManPiNum(pFrames) / nTruePis;
+    assert( nTruePis * nFrames == Aig_ManPiNum(pFrames) );
+    assert( nTruePos * nFrames == Aig_ManPoNum(pFrames) );
+    // find the PO that failed
+    iPo = -1;
+    iFrame = -1;
+    Aig_ManForEachPo( pFrames, pObj, i )
+        if ( pObj->Id == pModel[Aig_ManPiNum(pFrames)] )
+        {
+            iPo = i % nTruePos;
+            iFrame = i / nTruePos;
+            break;
+        }
+    assert( iPo >= 0 );
+    // allocate the counter example
+    pCex = Ssw_SmlAllocCounterExample( Aig_ManRegNum(pAig), nTruePis, iFrame + 1 );
+    pCex->iPo    = iPo;
+    pCex->iFrame = iFrame;
+
+    // copy the bit data
+    for ( i = 0; i < Aig_ManPiNum(pFrames); i++ )
+    {
+        if ( pModel[i] )
+            Aig_InfoSetBit( pCex->pData, pCex->nRegs + i );
+        if ( pCex->nRegs + i == pCex->nBits - 1 )
+            break;
+    }
+
+    // verify the counter example
+    if ( !Ssw_SmlRunCounterExample( pAig, pCex ) )
+    {
+        printf( "Ssw_SmlGetCounterExample(): Counter-example is invalid.\n" );
+        Ssw_SmlFreeCounterExample( pCex );
+        pCex = NULL;
+    }
+    return pCex;
+
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Make the trivial counter-example for the trivially asserted output.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Ssw_Cex_t * Ssw_SmlTrivCounterExample( Aig_Man_t * pAig, int iFrameOut )
+{
+    Ssw_Cex_t * pCex;
+    int nTruePis, nTruePos, iPo, iFrame;
+    assert( Aig_ManRegNum(pAig) > 0 );
+    nTruePis = Aig_ManPiNum(pAig)-Aig_ManRegNum(pAig);
+    nTruePos = Aig_ManPoNum(pAig)-Aig_ManRegNum(pAig);
+    iPo = iFrameOut % nTruePos;
+    iFrame = iFrameOut / nTruePos;
+    // allocate the counter example
+    pCex = Ssw_SmlAllocCounterExample( Aig_ManRegNum(pAig), nTruePis, iFrame + 1 );
+    pCex->iPo    = iPo;
+    pCex->iFrame = iFrame;
+    return pCex;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Make the trivial counter-example for the trivially asserted output.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Ssw_Cex_t * Ssw_SmlDupCounterExample( Ssw_Cex_t * p, int nRegsNew )
+{
+    Ssw_Cex_t * pCex;
+    int i;
+    pCex = Ssw_SmlAllocCounterExample( nRegsNew, p->nPis, p->iFrame+1 );
+    pCex->iPo    = p->iPo;
+    pCex->iFrame = p->iFrame;
+    for ( i = p->nRegs; i < p->nBits; i++ )
+        if ( Aig_InfoHasBit(p->pData, i) )
+            Aig_InfoSetBit( pCex->pData, pCex->nRegs + i - p->nRegs );
+    return pCex;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Resimulates the counter-example.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Ssw_SmlWriteCounterExample( FILE * pFile, Aig_Man_t * pAig, Ssw_Cex_t * p )
+{
+    Ssw_Sml_t * pSml;
+    Aig_Obj_t * pObj;
+    int RetValue, i, k, iBit;
+    unsigned * pSims;
+    assert( Aig_ManRegNum(pAig) > 0 );
+    assert( Aig_ManRegNum(pAig) < Aig_ManPiNum(pAig) );
+    // start a new sequential simulator
+    pSml = Ssw_SmlStart( pAig, 0, p->iFrame+1, 1 );
+    // assign simulation info for the registers
+    iBit = 0;
+    Saig_ManForEachLo( pAig, pObj, i )
+//        Ssw_SmlObjAssignConst( pSml, pObj, Aig_InfoHasBit(p->pData, iBit++), 0 );
+        Ssw_SmlObjAssignConst( pSml, pObj, 0, 0 );
+    // assign simulation info for the primary inputs
+    iBit = p->nRegs;
+    for ( i = 0; i <= p->iFrame; i++ )
+        Saig_ManForEachPi( pAig, pObj, k )
+            Ssw_SmlObjAssignConst( pSml, pObj, Aig_InfoHasBit(p->pData, iBit++), i );
+    assert( iBit == p->nBits );
+    // run random simulation
+    Ssw_SmlSimulateOne( pSml );
+    // check if the given output has failed
+    RetValue = !Ssw_SmlNodeIsZero( pSml, Aig_ManPo(pAig, p->iPo) );
+
+    // write the output file
+    for ( i = 0; i <= p->iFrame; i++ )
+    {
+/*
+        Saig_ManForEachLo( pAig, pObj, k )
+        {
+            pSims = Ssw_ObjSim(pSml, pObj->Id);
+            fprintf( pFile, "%d", (int)(pSims[i] != 0) );
+        }
+        fprintf( pFile, " " );
+*/
+        Saig_ManForEachPi( pAig, pObj, k )
+        {
+            pSims = Ssw_ObjSim(pSml, pObj->Id);
+            fprintf( pFile, "%d", (int)(pSims[i] != 0) );
+        }
+/*
+        fprintf( pFile, " " );
+        Saig_ManForEachPo( pAig, pObj, k )
+        {
+            pSims = Ssw_ObjSim(pSml, pObj->Id);
+            fprintf( pFile, "%d", (int)(pSims[i] != 0) );
+        }
+        fprintf( pFile, " " );
+        Saig_ManForEachLi( pAig, pObj, k )
+        {
+            pSims = Ssw_ObjSim(pSml, pObj->Id);
+            fprintf( pFile, "%d", (int)(pSims[i] != 0) );
+        }
+*/
+        fprintf( pFile, "\n" );
+    }
+
+    Ssw_SmlStop( pSml );
+    return RetValue;
+}
+
+
+
+////////////////////////////////////////////////////////////////////////
+///                       END OF FILE                                ///
+////////////////////////////////////////////////////////////////////////
+
+
diff --git a/src/aig/ssw_old/sswSimSat.c b/src/aig/ssw_old/sswSimSat.c
new file mode 100644
index 00000000..cbb6d0c1
--- /dev/null
+++ b/src/aig/ssw_old/sswSimSat.c
@@ -0,0 +1,199 @@
+/**CFile****************************************************************
+
+  FileName    [sswSimSat.c]
+
+  SystemName  [ABC: Logic synthesis and verification system.]
+
+  PackageName [Inductive prover with constraints.]
+
+  Synopsis    [Performs resimulation using counter-examples.]
+
+  Author      [Alan Mishchenko]
+  
+  Affiliation [UC Berkeley]
+
+  Date        [Ver. 1.0. Started - September 1, 2008.]
+
+  Revision    [$Id: sswSimSat.c,v 1.00 2008/09/01 00:00:00 alanmi Exp $]
+
+***********************************************************************/
+
+#include "sswInt.h"
+
+////////////////////////////////////////////////////////////////////////
+///                        DECLARATIONS                              ///
+////////////////////////////////////////////////////////////////////////
+
+////////////////////////////////////////////////////////////////////////
+///                     FUNCTION DEFINITIONS                         ///
+////////////////////////////////////////////////////////////////////////
+
+/**Function*************************************************************
+
+  Synopsis    [Handle the counter-example.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ssw_ManResimulateBit( Ssw_Man_t * p, Aig_Obj_t * pCand, Aig_Obj_t * pRepr )
+{
+    Aig_Obj_t * pObj;
+    int i, RetValue1, RetValue2, clk = clock();
+    // set the PI simulation information
+    Aig_ManConst1(p->pAig)->fMarkB = 1;
+    Aig_ManForEachPi( p->pAig, pObj, i )
+        pObj->fMarkB = Aig_InfoHasBit( p->pPatWords, i );
+    // simulate internal nodes
+    Aig_ManForEachNode( p->pAig, pObj, i )
+        pObj->fMarkB = ( Aig_ObjFanin0(pObj)->fMarkB ^ Aig_ObjFaninC0(pObj) )
+                     & ( Aig_ObjFanin1(pObj)->fMarkB ^ Aig_ObjFaninC1(pObj) );
+    // check equivalence classes
+    RetValue1 = Ssw_ClassesRefineConst1( p->ppClasses, 0 );
+    RetValue2 = Ssw_ClassesRefine( p->ppClasses, 0 );
+    // make sure refinement happened
+    if ( Aig_ObjIsConst1(pRepr) ) 
+    {
+        assert( RetValue1 );
+        if ( RetValue1 == 0 )
+            printf( "\nSsw_ManResimulateBit() Error: RetValue1 does not hold.\n" );
+    }
+    else
+    {
+        assert( RetValue2 );
+        if ( RetValue2 == 0 )
+            printf( "\nSsw_ManResimulateBit() Error: RetValue2 does not hold.\n" );
+    }
+p->timeSimSat += clock() - clk;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Verifies the result of simulation.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ssw_ManResimulateWordVerify( Ssw_Man_t * p, int f )
+{
+    Aig_Obj_t * pObj, * pObjFraig;
+    unsigned uWord;
+    int Value1, Value2;
+    int i, nVarNum, Counter = 0;
+    Aig_ManForEachObj( p->pAig, pObj, i )
+    {
+        pObjFraig = Ssw_ObjFrame( p, pObj, f );
+        if ( pObjFraig == NULL )
+            continue;
+        nVarNum = Ssw_ObjSatNum( p, Aig_Regular(pObjFraig) );
+        if ( nVarNum == 0 )
+            continue;
+        Value1 = Ssw_ManGetSatVarValue( p, pObj, f );
+        uWord  = Ssw_SmlObjGetWord( p->pSml, pObj, 0, 0 );
+        Value2 = ((uWord != 0) ^ pObj->fPhase);
+        Counter += (Value1 != Value2);
+        if ( Value1 != Value2 )
+        {
+/*
+            int Value1f = Ssw_ManGetSatVarValue( p, Aig_ObjFanin0(pObj), f );
+            int Value2f = Ssw_ManGetSatVarValue( p, Aig_ObjFanin1(pObj), f );
+*/
+            int x = 0;
+            int Value3 = Ssw_ManGetSatVarValue( p, pObj, f );
+        }
+    }
+    if ( Counter )
+        printf( "Counter = %d.\n", Counter );
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Handle the counter-example.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ssw_ManResimulateWord( Ssw_Man_t * p, Aig_Obj_t * pCand, Aig_Obj_t * pRepr, int f )
+{
+    int RetValue1, RetValue2, clk = clock();
+    // set the PI simulation information
+    Ssw_SmlAssignDist1Plus( p->pSml, p->pPatWords );
+    // simulate internal nodes
+    Ssw_SmlSimulateOne( p->pSml );
+    Ssw_ManResimulateWordVerify( p, f );
+
+    // check equivalence classes
+    RetValue1 = Ssw_ClassesRefineConst1( p->ppClasses, 1 );
+    RetValue2 = Ssw_ClassesRefine( p->ppClasses, 1 );
+    // make sure refinement happened
+    if ( Aig_ObjIsConst1(pRepr) )
+    {
+        assert( RetValue1 );
+        if ( RetValue1 == 0 )
+            printf( "\nSsw_ManResimulateWord() Error: RetValue1 does not hold.\n" );
+    }
+    else
+    {
+        assert( RetValue2 );
+        if ( RetValue2 == 0 )
+            printf( "\nSsw_ManResimulateWord() Error: RetValue2 does not hold.\n" );
+    }
+p->timeSimSat += clock() - clk;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Handle the counter-example.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ssw_ManResimulateWord2( Ssw_Man_t * p, Aig_Obj_t * pCand, Aig_Obj_t * pRepr, int f )
+{
+    int RetValue1, RetValue2, clk = clock();
+    // set the PI simulation information
+    Ssw_SmlAssignDist1Plus( p->pSml, p->pPatWords2 );
+    // simulate internal nodes
+    Ssw_SmlSimulateOne( p->pSml );
+    Ssw_ManResimulateWordVerify( p, f );
+
+    // check equivalence classes
+    RetValue1 = Ssw_ClassesRefineConst1( p->ppClasses, 1 );
+    RetValue2 = Ssw_ClassesRefine( p->ppClasses, 1 );
+    // make sure refinement happened
+    if ( Aig_ObjIsConst1(pRepr) )
+    {
+        assert( RetValue1 );
+        if ( RetValue1 == 0 )
+            printf( "\nSsw_ManResimulateWord() Error: RetValue1 does not hold.\n" );
+    }
+    else
+    {
+        assert( RetValue2 );
+        if ( RetValue2 == 0 )
+            printf( "\nSsw_ManResimulateWord() Error: RetValue2 does not hold.\n" );
+    }
+p->timeSimSat += clock() - clk;
+
+}
+
+////////////////////////////////////////////////////////////////////////
+///                       END OF FILE                                ///
+////////////////////////////////////////////////////////////////////////
+
+
diff --git a/src/aig/ssw_old/sswSweep.c b/src/aig/ssw_old/sswSweep.c
new file mode 100644
index 00000000..b9d4ad63
--- /dev/null
+++ b/src/aig/ssw_old/sswSweep.c
@@ -0,0 +1,473 @@
+/**CFile****************************************************************
+
+  FileName    [sswSweep.c]
+
+  SystemName  [ABC: Logic synthesis and verification system.]
+
+  PackageName [Inductive prover with constraints.]
+
+  Synopsis    [One round of SAT sweeping.]
+
+  Author      [Alan Mishchenko]
+  
+  Affiliation [UC Berkeley]
+
+  Date        [Ver. 1.0. Started - September 1, 2008.]
+
+  Revision    [$Id: sswSweep.c,v 1.00 2008/09/01 00:00:00 alanmi Exp $]
+
+***********************************************************************/
+
+#include "sswInt.h"
+#include "bar.h"
+
+////////////////////////////////////////////////////////////////////////
+///                        DECLARATIONS                              ///
+////////////////////////////////////////////////////////////////////////
+
+////////////////////////////////////////////////////////////////////////
+///                     FUNCTION DEFINITIONS                         ///
+////////////////////////////////////////////////////////////////////////
+
+/**Function*************************************************************
+
+  Synopsis    [Mark nodes affected by sweep in the previous iteration.]
+
+  Description [Assumes that affected nodes are in p->ppClasses->vRefined.]
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ssw_ManSweepMarkRefinement( Ssw_Man_t * p )
+{
+    Vec_Ptr_t * vRefined, * vSupp;
+    Aig_Obj_t * pObj, * pObjLo, * pObjLi;
+    int i, k;
+    vRefined = Ssw_ClassesGetRefined( p->ppClasses );
+    if ( Vec_PtrSize(vRefined) == 0 )
+    {
+        Aig_ManForEachObj( p->pAig, pObj, i )
+            pObj->fMarkA = 1;
+        return;
+    }
+    // mark the nodes to be refined
+    Aig_ManCleanMarkA( p->pAig );
+    Vec_PtrForEachEntry( vRefined, pObj, i )
+    {
+        if ( Aig_ObjIsPi(pObj) )
+        {
+            pObj->fMarkA = 1;
+            continue;
+        }
+        assert( Aig_ObjIsNode(pObj) );
+        vSupp = Aig_Support( p->pAig, pObj );
+        Vec_PtrForEachEntry( vSupp, pObjLo, k )
+            pObjLo->fMarkA = 1;
+        Vec_PtrFree( vSupp );
+    }
+    // mark refinement
+    Aig_ManForEachNode( p->pAig, pObj, i )
+        pObj->fMarkA = Aig_ObjFanin0(pObj)->fMarkA | Aig_ObjFanin1(pObj)->fMarkA;
+    Saig_ManForEachLi( p->pAig, pObj, i )
+        pObj->fMarkA |= Aig_ObjFanin0(pObj)->fMarkA;
+    Saig_ManForEachLiLo( p->pAig, pObjLi, pObjLo, i )
+        pObjLo->fMarkA |= pObjLi->fMarkA;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Retrives value of the PI in the original AIG.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Ssw_ManGetSatVarValue( Ssw_Man_t * p, Aig_Obj_t * pObj, int f )
+{
+    Aig_Obj_t * pObjFraig;
+    int nVarNum, Value;
+//    assert( Aig_ObjIsPi(pObj) );
+    pObjFraig = Ssw_ObjFrame( p, pObj, f );
+    nVarNum = Ssw_ObjSatNum( p, Aig_Regular(pObjFraig) );
+    assert( nVarNum > 0 );
+    if ( nVarNum == 0 )
+        printf( "Variable is not assigned.\n" );
+    Value = (!nVarNum)? 0 : (Aig_IsComplement(pObjFraig) ^ sat_solver_var_value( p->pSat, nVarNum ));
+//    Value = (Aig_IsComplement(pObjFraig) ^ ((!nVarNum)? 0 : sat_solver_var_value( p->pSat, nVarNum )));
+//    Value = (!nVarNum)? Aig_ManRandom(0) & 1 : (Aig_IsComplement(pObjFraig) ^ sat_solver_var_value( p->pSat, nVarNum ));
+    if ( p->pPars->fPolarFlip )
+    {
+        if ( Aig_Regular(pObjFraig)->fPhase )  Value ^= 1;
+    }
+    return Value;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Copy pattern from the solver into the internal storage.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ssw_SmlSavePatternAig( Ssw_Man_t * p, int f )
+{
+    Aig_Obj_t * pObj;
+    int i;
+    memset( p->pPatWords, 0, sizeof(unsigned) * p->nPatWords );
+    Aig_ManForEachPi( p->pAig, pObj, i )
+        if ( Ssw_ManGetSatVarValue( p, pObj, f ) )
+            Aig_InfoSetBit( p->pPatWords, i );
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Copy pattern from the solver into the internal storage.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ssw_SmlSavePatternAig2( Ssw_Man_t * p, int f )
+{
+    Aig_Obj_t * pObj;
+    int i;
+    memset( p->pPatWords2, 0, sizeof(unsigned) * p->nPatWords );
+    Aig_ManForEachPi( p->pAig, pObj, i )
+        if ( Ssw_ManGetSatVarValue( p, pObj, f ) )
+            Aig_InfoSetBit( p->pPatWords2, i );
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Copy pattern from the solver into the internal storage.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ssw_SmlSavePatternAigPhase( Ssw_Man_t * p, int f )
+{
+    Aig_Obj_t * pObj;
+    int i;
+    memset( p->pPatWords, 0, sizeof(unsigned) * p->nPatWords );
+    Aig_ManForEachPi( p->pAig, pObj, i )
+        if ( Aig_ObjPhaseReal( Ssw_ObjFrame(p, pObj, f) ) )
+            Aig_InfoSetBit( p->pPatWords, i );
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Performs fraiging for one node.]
+
+  Description [Returns the fraiged node.]
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Ssw_ManSweepNode( Ssw_Man_t * p, Aig_Obj_t * pObj, int f, int fBmc )
+{ 
+    Aig_Obj_t * pObjRepr, * pObjFraig, * pObjFraig2, * pObjReprFraig;
+    int RetValue;
+    // get representative of this class
+    pObjRepr = Aig_ObjRepr( p->pAig, pObj );
+    if ( pObjRepr == NULL )
+        return 0;
+    // get the fraiged node
+    pObjFraig = Ssw_ObjFrame( p, pObj, f );
+    // get the fraiged representative
+    pObjReprFraig = Ssw_ObjFrame( p, pObjRepr, f );
+    // check if constant 0 pattern distinquishes these nodes
+    assert( pObjFraig != NULL && pObjReprFraig != NULL );
+    if ( (pObj->fPhase == pObjRepr->fPhase) != (Aig_ObjPhaseReal(pObjFraig) == Aig_ObjPhaseReal(pObjReprFraig)) )
+    {
+        p->nStrangers++;
+        Ssw_SmlSavePatternAigPhase( p, f );
+    }
+    else
+    { 
+        // if the fraiged nodes are the same, return
+        if ( Aig_Regular(pObjFraig) == Aig_Regular(pObjReprFraig) )
+            return 0; 
+        // count the number of skipped calls
+        if ( !pObj->fMarkA && !pObjRepr->fMarkA )
+            p->nRefSkip++;
+        else
+            p->nRefUse++;
+        // call equivalence checking
+        if ( p->pPars->fSkipCheck && !fBmc && !pObj->fMarkA && !pObjRepr->fMarkA )
+            RetValue = 1;
+        else if ( Aig_Regular(pObjFraig) != Aig_ManConst1(p->pFrames) )
+            RetValue = Ssw_NodesAreEquiv( p, Aig_Regular(pObjReprFraig), Aig_Regular(pObjFraig) );
+        else
+            RetValue = Ssw_NodesAreEquiv( p, Aig_Regular(pObjFraig), Aig_Regular(pObjReprFraig) );
+        if ( RetValue == 1 )  // proved equivalent
+        {
+            pObjFraig2 = Aig_NotCond( pObjReprFraig, pObj->fPhase ^ pObjRepr->fPhase );
+            Ssw_ObjSetFrame( p, pObj, f, pObjFraig2 );
+            return 0;
+        } 
+        if ( RetValue == -1 ) // timed out
+        {
+            Ssw_ClassesRemoveNode( p->ppClasses, pObj );
+            return 1;
+        }
+        // check if skipping calls works correctly
+        if ( p->pPars->fSkipCheck && !fBmc && !pObj->fMarkA && !pObjRepr->fMarkA )
+        {
+            assert( 0 );
+            printf( "\nSsw_ManSweepNode(): Error!\n" );
+        }
+        // disproved the equivalence
+        Ssw_SmlSavePatternAig( p, f );
+    } 
+    if ( !fBmc && p->pPars->fUniqueness && p->pPars->nFramesK > 1 && 
+        Ssw_ManUniqueOne( p, pObjRepr, pObj ) && p->iOutputLit == -1 )
+    { 
+        if ( Ssw_ManUniqueAddConstraint( p, p->vCommon, 0, 1 ) )
+        {
+            int RetValue2 = Ssw_NodesAreEquiv( p, Aig_Regular(pObjReprFraig), Aig_Regular(pObjFraig) );
+            p->iOutputLit = -1;
+
+            {
+                int Flag = 0;
+                if ( Flag )
+                {
+                    Aig_Obj_t * pFan0 = Aig_ObjFanin0(pObj);
+                    Aig_Obj_t * pFan1 = Aig_ObjFanin1(pObj);
+                    Aig_Obj_t * pFan00 = Aig_ObjFanin0(pFan0);
+                    Aig_Obj_t * pFan01 = Aig_ObjFanin1(pFan0);
+                    Aig_Obj_t * pFan10 = Aig_ObjFanin0(pFan1);
+                    Aig_Obj_t * pFan11 = Aig_ObjFanin1(pFan1);
+                }
+            }
+
+            if ( RetValue2 == 0 )
+            {
+                int x = Ssw_ManUniqueOne( p, pObjRepr, pObj );
+//                Ssw_SmlSavePatternAig2( p, f );
+//                Ssw_ManResimulateWord2( p, pObj, pObjRepr, f );
+                Ssw_SmlSavePatternAig( p, f );
+                Ssw_ManResimulateWord( p, pObj, pObjRepr, f );
+                if ( Aig_ObjRepr( p->pAig, pObj ) == pObjRepr )
+                    printf( "Ssw_ManSweepNode(): Refinement did not happen!!!!!!!!!!!!!!!!!!!!.\n" );
+                return 1;
+            }
+            return 0;
+
+
+/*
+            int RetValue;
+            assert( p->iOutputLit > -1 );
+            RetValue = Ssw_ManSweepNode( p, pObj, f, 0 );
+            p->iOutputLit = -1;
+            return RetValue;
+*/
+        }
+    }
+    if ( p->pPars->nConstrs == 0 )
+        Ssw_ManResimulateWord( p, pObj, pObjRepr, f );
+    else
+        Ssw_ManResimulateBit( p, pObj, pObjRepr );
+    assert( Aig_ObjRepr( p->pAig, pObj ) != pObjRepr );
+    if ( Aig_ObjRepr( p->pAig, pObj ) == pObjRepr )
+        printf( "Ssw_ManSweepNode(): Refinement did not happen.\n" );
+    return 1;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Performs fraiging for the internal nodes.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Ssw_ManSweepBmc( Ssw_Man_t * p )
+{
+    Bar_Progress_t * pProgress = NULL;
+    Aig_Obj_t * pObj, * pObjNew, * pObjLi, * pObjLo;
+    int i, f, clk;
+clk = clock();
+
+    // start initialized timeframes
+    p->pFrames = Aig_ManStart( Aig_ManObjNumMax(p->pAig) * p->pPars->nFramesK );
+    Saig_ManForEachLo( p->pAig, pObj, i )
+        Ssw_ObjSetFrame( p, pObj, 0, Aig_ManConst0(p->pFrames) );
+
+    // sweep internal nodes
+    p->fRefined = 0;
+    if ( p->pPars->fVerbose )
+        pProgress = Bar_ProgressStart( stdout, Aig_ManObjNumMax(p->pAig) * p->pPars->nFramesK );
+    Ssw_ManStartSolver( p );
+    for ( f = 0; f < p->pPars->nFramesK; f++ )
+    {
+        // map constants and PIs
+        Ssw_ObjSetFrame( p, Aig_ManConst1(p->pAig), f, Aig_ManConst1(p->pFrames) );
+        Saig_ManForEachPi( p->pAig, pObj, i )
+        { 
+            pObjNew = Aig_ObjCreatePi(p->pFrames);
+            Ssw_ObjSetFrame( p, pObj, f, pObjNew );
+            Ssw_CnfNodeAddToSolver( p, Aig_Regular(pObjNew) );
+        }
+        // sweep internal nodes
+        Aig_ManForEachNode( p->pAig, pObj, i )
+        {
+            if ( p->pPars->fVerbose )
+                Bar_ProgressUpdate( pProgress, Aig_ManObjNumMax(p->pAig) * f + i, NULL );
+            pObjNew = Aig_And( p->pFrames, Ssw_ObjChild0Fra(p, pObj, f), Ssw_ObjChild1Fra(p, pObj, f) );
+            Ssw_ObjSetFrame( p, pObj, f, pObjNew );
+            p->fRefined |= Ssw_ManSweepNode( p, pObj, f, 1 );
+        }
+        // quit if this is the last timeframe
+        if ( f == p->pPars->nFramesK - 1 )
+            break;
+        // transfer latch input to the latch outputs 
+        // build logic cones for register outputs
+        Saig_ManForEachLiLo( p->pAig, pObjLi, pObjLo, i )
+        {
+            pObjNew = Ssw_ObjChild0Fra(p, pObjLi,f);
+            Ssw_ObjSetFrame( p, pObjLo, f+1, pObjNew );
+            Ssw_CnfNodeAddToSolver( p, Aig_Regular(pObjNew) );
+        }
+    }
+    if ( p->pPars->fVerbose )
+        Bar_ProgressStop( pProgress );
+
+    // cleanup
+//    Ssw_ClassesCheck( p->ppClasses );
+p->timeBmc += clock() - clk;
+    return p->fRefined;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Performs fraiging for the internal nodes.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Ssw_ManSweep( Ssw_Man_t * p )
+{
+    Bar_Progress_t * pProgress = NULL;
+    Aig_Obj_t * pObj, * pObj2, * pObjNew;
+    int nConstrPairs, clk, i, f;
+    int v;
+
+    // perform speculative reduction
+clk = clock();
+    // create timeframes
+    p->pFrames = Ssw_FramesWithClasses( p );
+    // add constraints
+    Ssw_ManStartSolver( p );
+//    nConstrPairs = Aig_ManPoNum(p->pFrames)-Aig_ManRegNum(p->pAig);
+    nConstrPairs = Aig_ManPoNum(p->pFrames)-p->nFrames*Aig_ManRegNum(p->pAig);
+    assert( (nConstrPairs & 1) == 0 );
+    for ( i = 0; i < nConstrPairs; i += 2 )
+    {
+        pObj  = Aig_ManPo( p->pFrames, i   );
+        pObj2 = Aig_ManPo( p->pFrames, i+1 );
+        Ssw_NodesAreConstrained( p, Aig_ObjChild0(pObj), Aig_ObjChild0(pObj2) );
+    }
+/*
+    // build logic cones for register inputs
+    for ( i = 0; i < Aig_ManRegNum(p->pAig); i++ )
+    {
+        pObj  = Aig_ManPo( p->pFrames, nConstrPairs + i );
+        Ssw_CnfNodeAddToSolver( p, Aig_ObjFanin0(pObj) );
+    }
+*/
+p->timeReduce += clock() - clk;
+
+    // mark nodes that do not have to be refined
+clk = clock();
+    if ( p->pPars->fSkipCheck )
+        Ssw_ManSweepMarkRefinement( p );
+p->timeMarkCones += clock() - clk;
+
+//Ssw_ManUnique( p );
+
+    // map constants and PIs of the last frame
+    f = p->pPars->nFramesK;
+    Ssw_ObjSetFrame( p, Aig_ManConst1(p->pAig), f, Aig_ManConst1(p->pFrames) );
+    Saig_ManForEachPi( p->pAig, pObj, i )
+        Ssw_ObjSetFrame( p, pObj, f, Aig_ObjCreatePi(p->pFrames) );
+////    
+    // bring up the previous frames
+//    if ( p->pPars->fUniqueness )
+        for ( v = 0; v <= f; v++ )
+//            Saig_ManForEachLo( p->pAig, pObj, i )
+            Aig_ManForEachPi( p->pAig, pObj, i )
+        {
+/*
+            if ( i == 53 && v == 1 )
+            {
+                int x = 0;
+            }
+*/
+                Ssw_CnfNodeAddToSolver( p, Aig_Regular(Ssw_ObjFrame(p, pObj, v)) );
+        }
+////
+    sat_solver_simplify( p->pSat );
+    // make sure LOs are assigned
+    Saig_ManForEachLo( p->pAig, pObj, i )
+        assert( Ssw_ObjFrame( p, pObj, f ) != NULL );
+    // sweep internal nodes
+    p->fRefined = 0;
+    p->nSatFailsReal = 0;
+    p->nRefUse = p->nRefSkip = 0;
+    p->nUniques = 0;
+    Ssw_ClassesClearRefined( p->ppClasses );
+    if ( p->pPars->fVerbose )
+        pProgress = Bar_ProgressStart( stdout, Aig_ManObjNumMax(p->pAig) );
+    Aig_ManForEachObj( p->pAig, pObj, i )
+    {
+        if ( p->pPars->fVerbose )
+            Bar_ProgressUpdate( pProgress, i, NULL );
+        if ( Saig_ObjIsLo(p->pAig, pObj) )
+            p->fRefined |= Ssw_ManSweepNode( p, pObj, f, 0 );
+        else if ( Aig_ObjIsNode(pObj) )
+        { 
+            pObj->fMarkA = Aig_ObjFanin0(pObj)->fMarkA | Aig_ObjFanin1(pObj)->fMarkA;
+            pObjNew = Aig_And( p->pFrames, Ssw_ObjChild0Fra(p, pObj, f), Ssw_ObjChild1Fra(p, pObj, f) );
+            Ssw_ObjSetFrame( p, pObj, f, pObjNew );
+            p->fRefined |= Ssw_ManSweepNode( p, pObj, f, 0 );
+        }
+    }
+    p->nSatFailsTotal += p->nSatFailsReal;
+    if ( p->pPars->fVerbose )
+        Bar_ProgressStop( pProgress );
+
+    // cleanup
+//    Ssw_ClassesCheck( p->ppClasses );
+    return p->fRefined;
+}
+
+////////////////////////////////////////////////////////////////////////
+///                       END OF FILE                                ///
+////////////////////////////////////////////////////////////////////////
+
+
diff --git a/src/aig/ssw_old/sswUnique.c b/src/aig/ssw_old/sswUnique.c
new file mode 100644
index 00000000..2beeed09
--- /dev/null
+++ b/src/aig/ssw_old/sswUnique.c
@@ -0,0 +1,290 @@
+/**CFile****************************************************************
+
+  FileName    [sswSat.c]
+
+  SystemName  [ABC: Logic synthesis and verification system.]
+
+  PackageName [Inductive prover with constraints.]
+
+  Synopsis    [On-demand uniqueness constraints.]
+
+  Author      [Alan Mishchenko]
+  
+  Affiliation [UC Berkeley]
+
+  Date        [Ver. 1.0. Started - September 1, 2008.]
+
+  Revision    [$Id: sswSat.c,v 1.00 2008/09/01 00:00:00 alanmi Exp $]
+
+***********************************************************************/
+
+#include "sswInt.h"
+
+////////////////////////////////////////////////////////////////////////
+///                        DECLARATIONS                              ///
+////////////////////////////////////////////////////////////////////////
+
+////////////////////////////////////////////////////////////////////////
+///                     FUNCTION DEFINITIONS                         ///
+////////////////////////////////////////////////////////////////////////
+
+/**Function*************************************************************
+
+  Synopsis    [Returns the result of merging the two vectors.]
+
+  Description [Assumes that the vectors are sorted in the increasing order.]
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+static inline void Vec_PtrTwoMerge( Vec_Ptr_t * vArr1, Vec_Ptr_t * vArr2, Vec_Ptr_t * vArr )
+{
+    Aig_Obj_t ** pBeg  = (Aig_Obj_t **)vArr->pArray;
+    Aig_Obj_t ** pBeg1 = (Aig_Obj_t **)vArr1->pArray;
+    Aig_Obj_t ** pBeg2 = (Aig_Obj_t **)vArr2->pArray;
+    Aig_Obj_t ** pEnd1 = (Aig_Obj_t **)vArr1->pArray + vArr1->nSize;
+    Aig_Obj_t ** pEnd2 = (Aig_Obj_t **)vArr2->pArray + vArr2->nSize;
+    Vec_PtrGrow( vArr, Vec_PtrSize(vArr1) + Vec_PtrSize(vArr2) );
+    pBeg  = (Aig_Obj_t **)vArr->pArray;
+    while ( pBeg1 < pEnd1 && pBeg2 < pEnd2 )
+    {
+        if ( (*pBeg1)->Id == (*pBeg2)->Id )
+            *pBeg++ = *pBeg1++, pBeg2++;
+        else if ( (*pBeg1)->Id < (*pBeg2)->Id )
+            *pBeg++ = *pBeg1++;
+        else 
+            *pBeg++ = *pBeg2++;
+    }
+    while ( pBeg1 < pEnd1 )
+        *pBeg++ = *pBeg1++;
+    while ( pBeg2 < pEnd2 )
+        *pBeg++ = *pBeg2++;
+    vArr->nSize = pBeg - (Aig_Obj_t **)vArr->pArray;
+    assert( vArr->nSize <= vArr->nCap );
+    assert( vArr->nSize >= vArr1->nSize );
+    assert( vArr->nSize >= vArr2->nSize );
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Returns the result of merging the two vectors.]
+
+  Description [Assumes that the vectors are sorted in the increasing order.]
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+static inline void Vec_PtrTwoCommon( Vec_Ptr_t * vArr1, Vec_Ptr_t * vArr2, Vec_Ptr_t * vArr )
+{
+    Aig_Obj_t ** pBeg  = (Aig_Obj_t **)vArr->pArray;
+    Aig_Obj_t ** pBeg1 = (Aig_Obj_t **)vArr1->pArray;
+    Aig_Obj_t ** pBeg2 = (Aig_Obj_t **)vArr2->pArray;
+    Aig_Obj_t ** pEnd1 = (Aig_Obj_t **)vArr1->pArray + vArr1->nSize;
+    Aig_Obj_t ** pEnd2 = (Aig_Obj_t **)vArr2->pArray + vArr2->nSize;
+    Vec_PtrGrow( vArr, AIG_MIN( Vec_PtrSize(vArr1), Vec_PtrSize(vArr2) ) );
+    pBeg  = (Aig_Obj_t **)vArr->pArray;
+    while ( pBeg1 < pEnd1 && pBeg2 < pEnd2 )
+    {
+        if ( (*pBeg1)->Id == (*pBeg2)->Id )
+            *pBeg++ = *pBeg1++, pBeg2++;
+        else if ( (*pBeg1)->Id < (*pBeg2)->Id )
+//            *pBeg++ = *pBeg1++;
+            pBeg1++;
+        else 
+//            *pBeg++ = *pBeg2++;
+            pBeg2++;
+    }
+//    while ( pBeg1 < pEnd1 )
+//        *pBeg++ = *pBeg1++;
+//    while ( pBeg2 < pEnd2 )
+//        *pBeg++ = *pBeg2++;
+    vArr->nSize = pBeg - (Aig_Obj_t **)vArr->pArray;
+    assert( vArr->nSize <= vArr->nCap );
+    assert( vArr->nSize <= vArr1->nSize );
+    assert( vArr->nSize <= vArr2->nSize );
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Returns 1 if uniqueness constraints can be added.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Ssw_ManUniqueOne( Ssw_Man_t * p, Aig_Obj_t * pRepr, Aig_Obj_t * pObj )
+{
+    int fVerbose = 1;
+    Aig_Obj_t * ppObjs[2], * pTemp;
+    Vec_Ptr_t * vSupp, * vSupp2;
+    int i, k, Value0, Value1, RetValue;
+    assert( p->pPars->nFramesK > 1 );
+
+    vSupp  = Vec_PtrAlloc( 100 );
+    vSupp2 = Vec_PtrAlloc( 100 );
+    Vec_PtrClear( p->vCommon );
+
+    // compute the first support in terms of LOs
+    ppObjs[0] = pRepr; 
+    ppObjs[1] = pObj;
+    Aig_SupportNodes( p->pAig, ppObjs, 2, vSupp );
+    // modify support to be in terms of LIs
+    k = 0;
+    Vec_PtrForEachEntry( vSupp, pTemp, i )
+        if ( Saig_ObjIsLo(p->pAig, pTemp) )
+            Vec_PtrWriteEntry( vSupp, k++, Saig_ObjLoToLi(p->pAig, pTemp) );
+    Vec_PtrShrink( vSupp, k );
+    // compute the support of support
+    Aig_SupportNodes( p->pAig, (Aig_Obj_t **)Vec_PtrArray(vSupp), Vec_PtrSize(vSupp), vSupp2 );
+    // return support to LO
+    Vec_PtrForEachEntry( vSupp, pTemp, i )
+        Vec_PtrWriteEntry( vSupp, i, Saig_ObjLiToLo(p->pAig, pTemp) );
+    // find the number of common vars
+    Vec_PtrSort( vSupp, Aig_ObjCompareIdIncrease );
+    Vec_PtrSort( vSupp2, Aig_ObjCompareIdIncrease );
+    Vec_PtrTwoCommon( vSupp, vSupp2, p->vCommon );
+//    Vec_PtrTwoMerge( vSupp, vSupp2, p->vCommon );
+
+/*
+    {
+        Vec_Ptr_t * vNew = Vec_PtrDup(vSupp);
+        Vec_PtrUniqify( vNew, Aig_ObjCompareIdIncrease );
+        if ( Vec_PtrSize(vNew) != Vec_PtrSize(vSupp) )
+            printf( "Not unique!\n" );
+        Vec_PtrFree( vNew );
+        Vec_PtrForEachEntry( vSupp, pTemp, i )
+            printf( "%d ", pTemp->Id );
+        printf( "\n" );
+    }
+    {
+        Vec_Ptr_t * vNew = Vec_PtrDup(vSupp2);
+        Vec_PtrUniqify( vNew, Aig_ObjCompareIdIncrease );
+        if ( Vec_PtrSize(vNew) != Vec_PtrSize(vSupp2) )
+            printf( "Not unique!\n" );
+        Vec_PtrFree( vNew );
+        Vec_PtrForEachEntry( vSupp2, pTemp, i )
+            printf( "%d ", pTemp->Id );
+        printf( "\n" );
+    }
+    {
+        Vec_Ptr_t * vNew = Vec_PtrDup(p->vCommon);
+        Vec_PtrUniqify( vNew, Aig_ObjCompareIdIncrease );
+        if ( Vec_PtrSize(vNew) != Vec_PtrSize(p->vCommon) )
+            printf( "Not unique!\n" );
+        Vec_PtrFree( vNew );
+        Vec_PtrForEachEntry( p->vCommon, pTemp, i )
+            printf( "%d ", pTemp->Id );
+        printf( "\n" );
+    }
+*/
+
+    if ( fVerbose )
+        printf( "Node = %5d : One = %3d. Two = %3d. Common = %3d.  ",
+            Aig_ObjId(pObj), Vec_PtrSize(vSupp), Vec_PtrSize(vSupp2), Vec_PtrSize(p->vCommon) );
+
+//    Vec_PtrClear( vSupp );
+//    Vec_PtrForEachEntry( vSupp2, pTemp, i )
+//        Vec_PtrPush( vSupp, pTemp );
+
+    // check the current values
+    RetValue = 1;
+//    Vec_PtrForEachEntry( p->vCommon, pTemp, i )
+    Vec_PtrForEachEntry( vSupp, pTemp, i )
+    {
+        Value0 = Ssw_ManGetSatVarValue( p, pTemp, 0 );
+        Value1 = Ssw_ManGetSatVarValue( p, pTemp, 1 );
+        if ( Value0 != Value1 )
+            RetValue = 0;
+        if ( fVerbose )
+            printf( "%d", Value0 ^ Value1 );
+    }
+    if ( Vec_PtrSize(p->vCommon) == 0 )
+        RetValue = 0;
+
+    Vec_PtrForEachEntry( vSupp, pTemp, i )
+        printf( " %d", pTemp->Id );
+
+    if ( fVerbose )
+        printf( "\n" );
+
+
+    Vec_PtrClear( p->vCommon );
+    Vec_PtrForEachEntry( vSupp, pTemp, i )
+        Vec_PtrPush( p->vCommon, pTemp );
+
+    Vec_PtrFree( vSupp );
+    Vec_PtrFree( vSupp2 );
+    return RetValue;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Returns the output of the uniqueness constraint.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Ssw_ManUniqueAddConstraint( Ssw_Man_t * p, Vec_Ptr_t * vCommon, int f1, int f2 )
+{
+    Aig_Obj_t * pObj, * pObj1New, * pObj2New, * pMiter, * pTotal;
+    int i, pLits[2];
+//    int RetValue;
+    assert( Vec_PtrSize(vCommon) > 0 );
+    // generate the constraint
+    pTotal = Aig_ManConst0(p->pFrames);
+    Vec_PtrForEachEntry( vCommon, pObj, i )
+    {
+        assert( Saig_ObjIsLo(p->pAig, pObj) );
+        pObj1New = Ssw_ObjFrame( p, pObj, f1 );
+        pObj2New = Ssw_ObjFrame( p, pObj, f2 );
+        pMiter = Aig_Exor( p->pFrames, pObj1New, pObj2New );
+        pTotal = Aig_Or( p->pFrames, pTotal, pMiter );
+    }
+/*
+    if ( Aig_ObjIsConst1(Aig_Regular(pTotal)) )
+    {
+//        printf( "Skipped\n" );
+        return 0;
+    }
+*/
+    p->nUniques++;
+    // create CNF
+//    {
+//        int Num1 = p->nSatVars;
+    Ssw_CnfNodeAddToSolver( p, Aig_Regular(pTotal) );
+//    printf( "Created variable %d while vars are %d. (diff = %d)\n", 
+//        Ssw_ObjSatNum( p, Aig_Regular(pTotal) ), p->nSatVars, p->nSatVars - Num1 );
+//    }
+    // add output constraint
+    pLits[0] = toLitCond( Ssw_ObjSatNum(p,Aig_Regular(pTotal)), Aig_IsComplement(pTotal) );
+/*
+    RetValue = sat_solver_addclause( p->pSat, pLits, pLits + 1 );
+    assert( RetValue );
+    // simplify the solver
+    if ( p->pSat->qtail != p->pSat->qhead )
+    {
+        RetValue = sat_solver_simplify(p->pSat);
+        assert( RetValue != 0 );
+    }
+*/
+    assert( p->iOutputLit == -1 );
+    p->iOutputLit = pLits[0];
+    return 1;
+}
+
+////////////////////////////////////////////////////////////////////////
+///                       END OF FILE                                ///
+////////////////////////////////////////////////////////////////////////
+
+
diff --git a/src/base/abci/abc.c b/src/base/abci/abc.c
index 4f46f3a2..50fb11ac 100644
--- a/src/base/abci/abc.c
+++ b/src/base/abci/abc.c
@@ -254,6 +254,7 @@ static int Abc_CommandAbc8Zero       ( Abc_Frame_t * pAbc, int argc, char ** arg
 static int Abc_CommandAbc8Cec        ( Abc_Frame_t * pAbc, int argc, char ** argv );
 static int Abc_CommandAbc8DSec       ( Abc_Frame_t * pAbc, int argc, char ** argv );
 
+static int Abc_CommandAbcTestNew     ( Abc_Frame_t * pAbc, int argc, char ** argv );
 
 ////////////////////////////////////////////////////////////////////////
 ///                     FUNCTION DEFINITIONS                         ///
@@ -518,6 +519,7 @@ void Abc_Init( Abc_Frame_t * pAbc )
     Cmd_CommandAdd( pAbc, "ABC8",         "*cec",          Abc_CommandAbc8Cec,          0 );
     Cmd_CommandAdd( pAbc, "ABC8",         "*dsec",         Abc_CommandAbc8DSec,         0 );
  
+    Cmd_CommandAdd( pAbc, "Various",      "testnew",         Abc_CommandAbcTestNew,     0 );
 
 //    Cmd_CommandAdd( pAbc, "Verification", "trace_start",   Abc_CommandTraceStart,       0 );
 //    Cmd_CommandAdd( pAbc, "Verification", "trace_check",   Abc_CommandTraceCheck,       0 );
@@ -4919,22 +4921,24 @@ int Abc_CommandDemiter( Abc_Frame_t * pAbc, int argc, char ** argv )
 {
     FILE * pOut, * pErr;
     Abc_Ntk_t * pNtk;//, * pNtkRes;
-    int fComb;
+    int fSeq;
     int c;
     extern int Abc_NtkDemiter( Abc_Ntk_t * pNtk );
+    extern int Abc_NtkDarDemiter( Abc_Ntk_t * pNtk );
 
     pNtk = Abc_FrameReadNtk(pAbc);
     pOut = Abc_FrameReadOut(pAbc);
     pErr = Abc_FrameReadErr(pAbc);
 
     // set defaults
+    fSeq = 1;
     Extra_UtilGetoptReset();
-    while ( ( c = Extra_UtilGetopt( argc, argv, "ch" ) ) != EOF )
+    while ( ( c = Extra_UtilGetopt( argc, argv, "sh" ) ) != EOF )
     {
         switch ( c )
         {
-        case 'c':
-            fComb ^= 1;
+        case 's':
+            fSeq ^= 1;
             break;
         default:
             goto usage;
@@ -4947,12 +4951,6 @@ int Abc_CommandDemiter( Abc_Frame_t * pAbc, int argc, char ** argv )
         return 1;
     }
 
-    if ( Abc_NtkPoNum(pNtk) != 1 )
-    {
-        fprintf( pErr, "The network is not a miter.\n" );
-        return 1;
-    }
-
     if ( !Abc_NodeIsExorType(Abc_ObjFanin0(Abc_NtkPo(pNtk,0))) )
     {
         fprintf( pErr, "The miter's PO is not an EXOR.\n" );
@@ -4960,19 +4958,35 @@ int Abc_CommandDemiter( Abc_Frame_t * pAbc, int argc, char ** argv )
     }
 
     // get the new network
-    if ( !Abc_NtkDemiter( pNtk ) )
+    if ( fSeq )
     {
-        fprintf( pErr, "Demitering has failed.\n" );
-        return 1;
+        if ( !Abc_NtkDarDemiter( pNtk ) )
+        {
+            fprintf( pErr, "Demitering has failed.\n" );
+            return 1;
+        }
+    }
+    else
+    {
+        if ( Abc_NtkPoNum(pNtk) != 1 )
+        {
+            fprintf( pErr, "The network is not a single-output miter.\n" );
+            return 1;
+        }
+        if ( !Abc_NtkDemiter( pNtk ) )
+        {
+            fprintf( pErr, "Demitering has failed.\n" );
+            return 1;
+        }
     }
     // replace the current network
 //    Abc_FrameReplaceCurrentNetwork( pAbc, pNtkRes );
     return 0;
 
 usage:
-    fprintf( pErr, "usage: demiter [-h]\n" );
+    fprintf( pErr, "usage: demiter [-sh]\n" );
     fprintf( pErr, "\t        removes topmost EXOR from the miter to create two POs\n" );
-//    fprintf( pErr, "\t-c    : computes combinational miter (latches as POs) [default = %s]\n", fComb? "yes": "no" );
+    fprintf( pErr, "\t-s    : applied multi-output algorithm [default = %s]\n", fSeq? "yes": "no" );
     fprintf( pErr, "\t-h    : print the command usage\n");
     return 1;
 }
@@ -7720,7 +7734,7 @@ int Abc_CommandTest( Abc_Frame_t * pAbc, int argc, char ** argv )
 //    extern void Aig_ProcedureTest();
     extern void Abc_NtkDarTest( Abc_Ntk_t * pNtk );
     extern Abc_Ntk_t * Abc_NtkDarTestNtk( Abc_Ntk_t * pNtk );
-
+    extern int Ssw_SecSpecialMiter( Aig_Man_t * pMiter, int fVerbose );
 
     pNtk = Abc_FrameReadNtk(pAbc);
     pOut = Abc_FrameReadOut(pAbc);
@@ -7922,6 +7936,7 @@ int Abc_CommandTest( Abc_Frame_t * pAbc, int argc, char ** argv )
     Abc_FrameReplaceCurrentNetwork( pAbc, pNtkRes );
 */
 
+/*
     pNtkRes = Abc_NtkDarTestNtk( pNtk );
     if ( pNtkRes == NULL )
     {
@@ -7930,6 +7945,9 @@ int Abc_CommandTest( Abc_Frame_t * pAbc, int argc, char ** argv )
     }
     // replace the current network
     Abc_FrameReplaceCurrentNetwork( pAbc, pNtkRes );
+*/
+
+    Abc_NtkDarTest( pNtk );
 
     return 0;
 usage:
@@ -13541,7 +13559,7 @@ int Abc_CommandSeqSweep2( Abc_Frame_t * pAbc, int argc, char ** argv )
     // set defaults
     Ssw_ManSetDefaultParams( pPars );
     Extra_UtilGetoptReset();
-    while ( ( c = Extra_UtilGetopt( argc, argv, "PQFCLNSplsfuvh" ) ) != EOF )
+    while ( ( c = Extra_UtilGetopt( argc, argv, "PQFCLNSplsfuvwh" ) ) != EOF )
     {
         switch ( c )
         {
@@ -13640,6 +13658,9 @@ int Abc_CommandSeqSweep2( Abc_Frame_t * pAbc, int argc, char ** argv )
         case 'v':
             pPars->fVerbose ^= 1;
             break;
+        case 'w':
+            pPars->fFlopVerbose ^= 1;
+            break;
         case 'h':
             goto usage;
         default:
@@ -13689,7 +13710,7 @@ int Abc_CommandSeqSweep2( Abc_Frame_t * pAbc, int argc, char ** argv )
     return 0;
 
 usage:
-    fprintf( pErr, "usage: scorr [-PQFCLNS <num>] [-plsfuvh]\n" );
+    fprintf( pErr, "usage: scorr [-PQFCLNS <num>] [-plsfuvwh]\n" );
     fprintf( pErr, "\t         performs sequential sweep using K-step induction\n" );
     fprintf( pErr, "\t-P num : max partition size (0 = no partitioning) [default = %d]\n", pPars->nPartSize );
     fprintf( pErr, "\t-Q num : partition overlap (0 = no overlap) [default = %d]\n", pPars->nOverSize );
@@ -13704,6 +13725,7 @@ usage:
     fprintf( pErr, "\t-f     : toggle filtering using interative BMC [default = %s]\n", pPars->fSemiFormal? "yes": "no" );
     fprintf( pErr, "\t-u     : toggle using uniqueness constraints [default = %s]\n", pPars->fUniqueness? "yes": "no" );
     fprintf( pErr, "\t-v     : toggle verbose output [default = %s]\n", pPars->fVerbose? "yes": "no" );
+    fprintf( pErr, "\t-w     : toggle printout of flop equivalences [default = %s]\n", pPars->fFlopVerbose? "yes": "no" );
     fprintf( pErr, "\t-h     : print the command usage\n");
     return 1;
 }
@@ -19634,6 +19656,64 @@ usage:
 }
 
 
+
+/**Function*************************************************************
+
+  Synopsis    []
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Abc_CommandAbcTestNew( Abc_Frame_t * pAbc, int argc, char ** argv )
+{
+    extern int Abc_NtkTestProcedure( Abc_Ntk_t * pNtk1, Abc_Ntk_t * pNtk2 );
+
+    Abc_Ntk_t * pNtk;
+    int c;
+
+    pNtk = Abc_FrameReadNtk(pAbc);
+
+    // set defaults
+    Extra_UtilGetoptReset();
+    while ( ( c = Extra_UtilGetopt( argc, argv, "h" ) ) != EOF )
+    {
+        switch ( c )
+        {
+        case 'h':
+            goto usage;
+        default:
+            goto usage;
+        }
+    }
+
+    if ( pNtk == NULL )
+    {
+        fprintf( stdout, "Empty network.\n" );
+        return 1;
+    }
+
+    if ( !Abc_NtkIsStrash( pNtk) )
+    {
+        fprintf( stdout, "The current network is not an AIG. Cannot continue.\n" );
+        return 1;
+    }
+
+//    Abc_NtkTestProcedure( pNtk, NULL );
+
+    return 0;
+
+usage:
+    fprintf( stdout, "usage: testnew [-h]\n" );
+    fprintf( stdout, "\t        new testing procedure\n" );
+    fprintf( stdout, "\t-h    : print the command usage\n");
+    return 1;
+}
+
+
 ////////////////////////////////////////////////////////////////////////
 ///                       END OF FILE                                ///
 ////////////////////////////////////////////////////////////////////////
diff --git a/src/base/abci/abc.zip b/src/base/abci/abc.zip
new file mode 100644
index 00000000..34df9a63
--- /dev/null
+++ b/src/base/abci/abc.zip
diff --git a/src/base/abci/abcDar.c b/src/base/abci/abcDar.c
index 98228c56..c64fb0f5 100644
--- a/src/base/abci/abcDar.c
+++ b/src/base/abci/abcDar.c
@@ -1240,6 +1240,96 @@ PRT( "Initial fraiging time", clock() - clk );
 
 /**Function*************************************************************
 
+  Synopsis    [Print Latch Equivalence Classes.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Abc_NtkPrintLatchEquivClasses( Abc_Ntk_t * pNtk, Aig_Man_t * pAig )
+{
+    bool header_dumped = false;
+    int num_orig_latches = Abc_NtkLatchNum(pNtk);
+    char **pNames = ALLOC( char *, num_orig_latches );
+    bool *p_irrelevant = ALLOC( bool, num_orig_latches );
+    char * pFlopName, * pReprName;
+    Aig_Obj_t * pFlop, * pRepr;
+    Abc_Obj_t * pNtkFlop; 
+    int repr_idx;
+    int i;
+
+    Abc_NtkForEachLatch( pNtk, pNtkFlop, i )
+    {
+        char *temp_name = Abc_ObjName( Abc_ObjFanout0(pNtkFlop) );
+        pNames[i] = ALLOC( char , strlen(temp_name)+1);
+        strcpy(pNames[i], temp_name);
+    }
+    i = 0;
+    
+    Aig_ManSetPioNumbers( pAig );
+    Saig_ManForEachLo( pAig, pFlop, i )
+    {
+        p_irrelevant[i] = false;
+        
+        pFlopName = pNames[i];
+
+        pRepr = Aig_ObjRepr(pAig, pFlop);
+
+        if ( pRepr == NULL )
+        {
+            // printf("Nothing equivalent to flop %s\n", pFlopName);
+            p_irrelevant[i] = true;
+            continue;
+        }
+
+        if (!header_dumped)
+        {
+            printf("Here are the flop equivalences:\n");
+            header_dumped = true;
+        }
+
+        // pRepr is representative of the equivalence class, to which pFlop belongs
+        if ( Aig_ObjIsConst1(pRepr) )
+        {
+            printf( "Original flop %s is proved equivalent to constant.\n", pFlopName );
+            // printf( "Original flop # %d is proved equivalent to constant.\n", i );
+            continue;
+        }
+
+        assert( Saig_ObjIsLo( pAig, pRepr ) );
+        repr_idx = Aig_ObjPioNum(pRepr) - Saig_ManPiNum(pAig);
+        pReprName = pNames[repr_idx];
+        printf( "Original flop %s is proved equivalent to flop %s.\n",  pFlopName, pReprName );
+        // printf( "Original flop # %d is proved equivalent to flop # %d.\n",  i, repr_idx );
+    }
+
+    header_dumped = false;
+    for (i=0; i<num_orig_latches; ++i)
+    {
+        if (p_irrelevant[i])
+        {
+            if (!header_dumped)
+            {
+                printf("The following flops have been deemed irrelevant:\n");
+                header_dumped = true;
+            }
+            printf("%s ", pNames[i]);
+        }
+        
+        FREE(pNames[i]);
+    }
+    if (header_dumped)
+        printf("\n");
+    
+    FREE(pNames);
+    FREE(p_irrelevant);
+}
+
+/**Function*************************************************************
+
   Synopsis    [Gives the current ABC network to AIG manager for processing.]
 
   Description []
@@ -1259,7 +1349,11 @@ Abc_Ntk_t * Abc_NtkDarSeqSweep2( Abc_Ntk_t * pNtk, Ssw_Pars_t * pPars )
         return NULL;
 
     pMan = Ssw_SignalCorrespondence( pTemp = pMan, pPars );
-    Aig_ManStop( pTemp );
+
+    if ( pPars->fFlopVerbose )
+        Abc_NtkPrintLatchEquivClasses(pNtk, pTemp);
+
+        Aig_ManStop( pTemp );
     if ( pMan == NULL )
         return NULL;
 
@@ -1474,6 +1568,47 @@ PRT( "Time", clock() - clk );
   SeeAlso     []
 
 ***********************************************************************/
+int Abc_NtkDarDemiter( Abc_Ntk_t * pNtk )
+{ 
+    Aig_Man_t * pMan, * pPart0, * pPart1, * pMiter;
+    // derive the AIG manager
+    pMan = Abc_NtkToDar( pNtk, 0, 1 );
+    if ( pMan == NULL )
+    {
+        printf( "Converting network into AIG has failed.\n" );
+        return 0;
+    }
+    if ( !Saig_ManDemiterSimple( pMan, &pPart0, &pPart1 ) )
+    {
+        printf( "Demitering has failed.\n" );
+        return 0;
+    }
+    Aig_ManDumpBlif( pPart0, "part0.blif", NULL, NULL );
+    Aig_ManDumpBlif( pPart1, "part1.blif", NULL, NULL );
+    printf( "The result of demitering is written into files \"%s\" and \"%s\".\n", "part0.blif", "part1.blif" );
+    // create two-level miter
+    pMiter = Saig_ManCreateMiterTwo( pPart0, pPart1, 2 );
+    Aig_ManDumpBlif( pMiter, "miter01.blif", NULL, NULL );
+    Aig_ManStop( pMiter );
+    printf( "The new miter is written into file \"%s\".\n", "miter01.blif" );
+
+    Aig_ManStop( pPart0 );
+    Aig_ManStop( pPart1 );
+    Aig_ManStop( pMan );
+    return 1;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Gives the current ABC network to AIG manager for processing.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
 int Abc_NtkDarProve( Abc_Ntk_t * pNtk, Fra_Sec_t * pSecPar )
 {
     Aig_Man_t * pMan;
@@ -2457,9 +2592,9 @@ void Abc_NtkDarReach( Abc_Ntk_t * pNtk, int nBddMax, int nIterMax, int fPartitio
 ***********************************************************************/
 void Abc_NtkDarTest( Abc_Ntk_t * pNtk )
 {
-    extern Aig_Man_t * Ssw_SignalCorrespondeceTestPairs( Aig_Man_t * pAig );
+//    extern Aig_Man_t * Ssw_SignalCorrespondeceTestPairs( Aig_Man_t * pAig );
 
-    Aig_Man_t * pMan, * pTemp;
+    Aig_Man_t * pMan;//, * pTemp;
     assert( Abc_NtkIsStrash(pNtk) );
     pMan = Abc_NtkToDar( pNtk, 0, 1 );
     if ( pMan == NULL )
@@ -2472,9 +2607,13 @@ Aig_ManStop( pMan );
 pMan = Saig_ManReadBlif( "_temp_.blif" );
 Aig_ManPrintStats( pMan );
 */
+/*
     Aig_ManSetRegNum( pMan, pMan->nRegs );
     pTemp = Ssw_SignalCorrespondeceTestPairs( pMan );
     Aig_ManStop( pTemp );
+*/
+    Ssw_SecSpecialMiter( pMan, 0 );
+
     Aig_ManStop( pMan );
 }
 
diff --git a/src/base/cmd/cmd.c b/src/base/cmd/cmd.c
index 75aa0064..4e0a4c95 100644
--- a/src/base/cmd/cmd.c
+++ b/src/base/cmd/cmd.c
@@ -50,6 +50,7 @@ static int CmdCommandEmpty         ( Abc_Frame_t * pAbc, int argc, char ** argv
 static int CmdCommandLs            ( Abc_Frame_t * pAbc, int argc, char ** argv );
 static int CmdCommandScrGen        ( Abc_Frame_t * pAbc, int argc, char ** argv );
 #endif
+static int CmdCommandVersion       ( Abc_Frame_t * pAbc, int argc, char ** argv );
 static int CmdCommandSis           ( Abc_Frame_t * pAbc, int argc, char ** argv );
 static int CmdCommandMvsis         ( Abc_Frame_t * pAbc, int argc, char ** argv );
 static int CmdCommandCapo          ( Abc_Frame_t * pAbc, int argc, char ** argv );
@@ -68,7 +69,7 @@ static int CmdCommandCapo          ( Abc_Frame_t * pAbc, int argc, char ** argv
 
 ******************************************************************************/
 void Cmd_Init( Abc_Frame_t * pAbc )
-{
+{ 
     pAbc->tCommands = st_init_table(strcmp, st_strhash);
     pAbc->tAliases  = st_init_table(strcmp, st_strhash);
     pAbc->tFlags    = st_init_table(strcmp, st_strhash);
@@ -91,6 +92,7 @@ void Cmd_Init( Abc_Frame_t * pAbc )
     Cmd_CommandAdd( pAbc, "Basic", "ls",        CmdCommandLs,             0 );
     Cmd_CommandAdd( pAbc, "Basic", "scrgen",    CmdCommandScrGen,         0 );
 #endif
+    Cmd_CommandAdd( pAbc, "Basic", "version",   CmdCommandVersion,        0); 
 
     Cmd_CommandAdd( pAbc, "Various", "sis",     CmdCommandSis,            1); 
     Cmd_CommandAdd( pAbc, "Various", "mvsis",   CmdCommandMvsis,          1); 
@@ -1910,6 +1912,22 @@ usage:
     return 1;                    // error exit 
 }
 
+/**Function********************************************************************
+
+  Synopsis    [Print the version string.]
+
+  Description []
+
+  SideEffects []
+
+  SeeAlso     []
+
+******************************************************************************/
+int CmdCommandVersion( Abc_Frame_t * pAbc, int argc, char **argv )
+{
+    printf("%s\n", Abc_UtilsGetVersion(pAbc));
+    return 0;
+}
 
 
 ////////////////////////////////////////////////////////////////////////
diff --git a/src/base/cmd/cmd.h b/src/base/cmd/cmd.h
index 030b77e8..9d0b8703 100644
--- a/src/base/cmd/cmd.h
+++ b/src/base/cmd/cmd.h
@@ -40,6 +40,17 @@ extern "C" {
 typedef struct MvCommand    Abc_Command;  // one command
 typedef struct MvAlias      Abc_Alias;    // one alias
 
+#ifdef WIN32
+#define DLLEXPORT __declspec(dllexport)
+#define DLLIMPORT __declspec(dllimport)
+#else  /* defined(WIN32) */
+#define DLLIMPORT
+#endif /* defined(WIN32) */
+
+#ifndef ABC_DLL
+#define ABC_DLL DLLIMPORT
+#endif
+
 ////////////////////////////////////////////////////////////////////////
 ///                       MACRO DEFINITIONS                          ///
 ////////////////////////////////////////////////////////////////////////
@@ -53,7 +64,7 @@ extern void        Cmd_Init();
 extern void        Cmd_End();
 /*=== cmdApi.c ========================================================*/
 extern void        Cmd_CommandAdd( Abc_Frame_t * pAbc, char * sGroup, char * sName, void * pFunc, int fChanges );
-extern int         Cmd_CommandExecute( Abc_Frame_t * pAbc, char * sCommand );
+extern ABC_DLL int Cmd_CommandExecute( Abc_Frame_t * pAbc, char * sCommand );
 /*=== cmdFlag.c ========================================================*/
 extern char *      Cmd_FlagReadByName( Abc_Frame_t * pAbc, char * flag );
 extern void        Cmd_FlagDeleteByName( Abc_Frame_t * pAbc, char * key );
diff --git a/src/base/io/io.c b/src/base/io/io.c
index 6d7948ab..6f326a27 100644
--- a/src/base/io/io.c
+++ b/src/base/io/io.c
@@ -1710,30 +1710,7 @@ int IoCommandWriteCounter( Abc_Frame_t * pAbc, int argc, char **argv )
     }
 
     // write the counter-example into the file
-    if ( pNtk->pModel )
-    {
-        Abc_Obj_t * pObj;
-        FILE * pFile = fopen( pFileName, "w" );
-        int i;
-        if ( pFile == NULL )
-        {
-            fprintf( stdout, "IoCommandWriteCounter(): Cannot open the output file \"%s\".\n", pFileName );
-            return 1;
-        }
-        if ( fNames )
-        {
-            Abc_NtkForEachPi( pNtk, pObj, i )
-                fprintf( pFile, "%s=%c ", Abc_ObjName(pObj), '0'+(pNtk->pModel[i]==1) );
-        }
-        else
-        {
-            Abc_NtkForEachPi( pNtk, pObj, i )
-                fprintf( pFile, "%c", '0'+(pNtk->pModel[i]==1) );
-        }
-        fprintf( pFile, "\n" );
-        fclose( pFile );
-    }
-    else
+    if ( pNtk->pSeqModel )
     { 
         Fra_Cex_t * pCex = pNtk->pSeqModel;
         Abc_Obj_t * pObj;
@@ -1771,6 +1748,29 @@ int IoCommandWriteCounter( Abc_Frame_t * pAbc, int argc, char **argv )
         fprintf( pFile, "\n" );
         fclose( pFile );
     }
+    else
+    {
+        Abc_Obj_t * pObj;
+        FILE * pFile = fopen( pFileName, "w" );
+        int i;
+        if ( pFile == NULL )
+        {
+            fprintf( stdout, "IoCommandWriteCounter(): Cannot open the output file \"%s\".\n", pFileName );
+            return 1;
+        }
+        if ( fNames )
+        {
+            Abc_NtkForEachPi( pNtk, pObj, i )
+                fprintf( pFile, "%s=%c ", Abc_ObjName(pObj), '0'+(pNtk->pModel[i]==1) );
+        }
+        else
+        {
+            Abc_NtkForEachPi( pNtk, pObj, i )
+                fprintf( pFile, "%c", '0'+(pNtk->pModel[i]==1) );
+        }
+        fprintf( pFile, "\n" );
+        fclose( pFile );
+    }
 
     return 0;
 
diff --git a/src/base/main/mainUtils.c b/src/base/main/mainUtils.c
index d69055a4..46469490 100644
--- a/src/base/main/mainUtils.c
+++ b/src/base/main/mainUtils.c
@@ -200,14 +200,26 @@ void Abc_UtilsSource( Abc_Frame_t * pAbc )
 
         if ( sPath1 && sPath2 ) {
             /* ~/.rc == .rc : Source the file only once */
-            (void) Cmd_CommandExecute(pAbc, "source -s ~/.abc.rc");
+            char *tmp_cmd = ALLOC(char, strlen(sPath1)+12);
+            (void) sprintf(tmp_cmd, "source -s %s", sPath1);
+            // (void) Cmd_CommandExecute(pAbc, "source -s ~/.abc.rc");
+            (void) Cmd_CommandExecute(pAbc, tmp_cmd);
+            FREE(tmp_cmd);
         }
         else {
             if (sPath1) {
-                (void) Cmd_CommandExecute(pAbc, "source -s ~/.abc.rc");
+                char *tmp_cmd = ALLOC(char, strlen(sPath1)+12);
+                (void) sprintf(tmp_cmd, "source -s %s", sPath1);
+                // (void) Cmd_CommandExecute(pAbc, "source -s ~/.abc.rc");
+                (void) Cmd_CommandExecute(pAbc, tmp_cmd);
+                FREE(tmp_cmd);
             }
             if (sPath2) {
-                (void) Cmd_CommandExecute(pAbc, "source -s .abc.rc");
+                char *tmp_cmd = ALLOC(char, strlen(sPath2)+12);
+                (void) sprintf(tmp_cmd, "source -s %s", sPath2);
+                // (void) Cmd_CommandExecute(pAbc, "source -s .abc.rc");
+                (void) Cmd_CommandExecute(pAbc, tmp_cmd);
+                FREE(tmp_cmd);
             }
         }
         if ( sPath1 ) FREE(sPath1);
diff --git a/src/misc/extra/extra.h b/src/misc/extra/extra.h
index d63ed5d3..beb5a4d0 100644
--- a/src/misc/extra/extra.h
+++ b/src/misc/extra/extra.h
@@ -76,6 +76,18 @@ extern "C" {
 /* Macro declarations                                                        */
 /*---------------------------------------------------------------------------*/
 
+#ifdef WIN32
+#define DLLEXPORT __declspec(dllexport)
+#define DLLIMPORT __declspec(dllimport)
+#else  /* defined(WIN32) */
+#define DLLIMPORT
+#endif /* defined(WIN32) */
+
+#ifndef ABC_DLL
+#define ABC_DLL DLLIMPORT
+#endif
+
+
 typedef unsigned char      uint8;
 typedef unsigned short     uint16;
 typedef unsigned int       uint32;
@@ -633,19 +645,19 @@ extern unsigned    Extra_TruthSemiCanonicize( unsigned * pInOut, unsigned * pAux
 #endif
 
 
-extern long        Extra_CpuTime();
-extern double      Extra_CpuTimeDouble();
-extern int         Extra_GetSoftDataLimit();
-extern void        Extra_UtilGetoptReset();
-extern int         Extra_UtilGetopt( int argc, char *argv[], char *optstring );
-extern char *      Extra_UtilPrintTime( long t );
-extern char *      Extra_UtilStrsav( char *s );
-extern char *      Extra_UtilTildeExpand( char *fname );
-extern char *      Extra_UtilFileSearch( char *file, char *path, char *mode );
-extern void        (*Extra_UtilMMoutOfMemory)();
+extern long          Extra_CpuTime();
+extern double        Extra_CpuTimeDouble();
+extern int           Extra_GetSoftDataLimit();
+extern ABC_DLL void  Extra_UtilGetoptReset();
+extern int           Extra_UtilGetopt( int argc, char *argv[], char *optstring );
+extern char *        Extra_UtilPrintTime( long t );
+extern char *        Extra_UtilStrsav( char *s );
+extern char *        Extra_UtilTildeExpand( char *fname );
+extern char *        Extra_UtilFileSearch( char *file, char *path, char *mode );
+extern void          (*Extra_UtilMMoutOfMemory)();
 
-extern char *      globalUtilOptarg;
-extern int         globalUtilOptind;
+extern char *        globalUtilOptarg;
+extern int           globalUtilOptind;
 
 /**AutomaticEnd***************************************************************/
 
diff --git a/src/sat/bsat/satChecker.c b/src/sat/bsat/satChecker.c
new file mode 100644
index 00000000..1488fe2f
--- /dev/null
+++ b/src/sat/bsat/satChecker.c
@@ -0,0 +1,187 @@
+/**CFile****************************************************************
+
+  FileName    [satChecker.c]
+
+  SystemName  [ABC: Logic synthesis and verification system.]
+
+  PackageName [SAT sat_solver.]
+
+  Synopsis    [Resolution proof checker.]
+
+  Author      [Alan Mishchenko]
+  
+  Affiliation [UC Berkeley]
+
+  Date        [Ver. 1.0. Started - June 20, 2005.]
+
+  Revision    [$Id: satChecker.c,v 1.4 2005/09/16 22:55:03 casem Exp $]
+
+***********************************************************************/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <assert.h>
+#include <time.h>
+#include "vec.h"
+
+////////////////////////////////////////////////////////////////////////
+///                        DECLARATIONS                              ///
+////////////////////////////////////////////////////////////////////////
+
+
+////////////////////////////////////////////////////////////////////////
+///                     FUNCTION DEFINITIONS                         ///
+////////////////////////////////////////////////////////////////////////
+
+/**Function*************************************************************
+
+  Synopsis    []
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Sat_PrintClause( Vec_Vec_t * vClauses, int Clause )
+{
+    Vec_Int_t * vClause;
+    int i, Entry;
+    printf( "Clause %d:  {", Clause );
+    vClause = Vec_VecEntry( vClauses, Clause );
+    Vec_IntForEachEntry( vClause, Entry, i )
+        printf( " %d", Entry );
+    printf( " }\n" );
+}
+
+/**Function*************************************************************
+
+  Synopsis    []
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Sat_ProofResolve( Vec_Vec_t * vClauses, int Result, int Clause1, int Clause2 )
+{
+    Vec_Int_t * vResult  = Vec_VecEntry( vClauses, Result );
+    Vec_Int_t * vClause1 = Vec_VecEntry( vClauses, Clause1 );
+    Vec_Int_t * vClause2 = Vec_VecEntry( vClauses, Clause2 );
+    int Entry1, Entry2, ResVar;
+    int i, j, Counter = 0;
+
+    Vec_IntForEachEntry( vClause1, Entry1, i )
+    Vec_IntForEachEntry( vClause2, Entry2, j )
+    if ( Entry1 == -Entry2 )
+    {
+        ResVar = Entry1;
+        Counter++;
+    }
+    if ( Counter != 1 )
+    {
+        printf( "Error: Clause %d = Resolve(%d, %d): The number of pivot vars is %d.\n", 
+            Result, Clause1, Clause2, Counter );
+        Sat_PrintClause( vClauses, Clause1 );
+        Sat_PrintClause( vClauses, Clause2 );
+        return 0;
+    }
+    // create new clause
+    assert( Vec_IntSize(vResult) == 0 );
+    Vec_IntForEachEntry( vClause1, Entry1, i )
+        if ( Entry1 != ResVar && Entry1 != -ResVar )
+            Vec_IntPushUnique( vResult, Entry1 );
+    assert( Vec_IntSize(vResult) + 1 == Vec_IntSize(vClause1) );
+    Vec_IntForEachEntry( vClause2, Entry2, i )
+        if ( Entry2 != ResVar && Entry2 != -ResVar )
+            Vec_IntPushUnique( vResult, Entry2 );
+    return 1;
+}
+
+/**Function*************************************************************
+
+  Synopsis    []
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Sat_ProofChecker( char * pFileName )
+{
+    FILE * pFile;
+    Vec_Vec_t * vClauses;
+    int c, i, Num, RetValue, Counter, Counter2, Clause1, Clause2;
+    // open the file
+    pFile = fopen( pFileName, "r" );
+    if ( pFile == NULL )
+        return;
+    // count the number of clauses
+    Counter = Counter2 = 0;
+    while ( (c = fgetc(pFile)) != EOF )
+    {
+        Counter += (c == '\n');
+        Counter2 += (c == '*');
+    }
+    vClauses = Vec_VecStart( Counter+1 );
+    printf( "The proof contains %d roots and %d resolution steps.\n", Counter-Counter2, Counter2 );
+    // read the clauses
+    rewind( pFile );
+    for ( i = 1 ; ; i++ )
+    {
+        RetValue = fscanf( pFile, "%d", &Num );
+        if ( RetValue != 1 )
+            break;
+        assert( Num == i );
+        while ( (c = fgetc( pFile )) == ' ' );
+        if ( c == '*' )
+        {
+            RetValue = fscanf( pFile, "%d %d", &Clause1, &Clause2 );
+            assert( RetValue == 2 );
+            RetValue = fscanf( pFile, "%d", &Num );
+            assert( RetValue == 1 );
+            assert( Num == 0 );
+            if ( !Sat_ProofResolve( vClauses, i, Clause1, Clause2 ) )
+            {
+                printf( "Error detected in the resolution proof.\n" );
+                Vec_VecFree( vClauses );
+                fclose( pFile );
+                return;
+            }
+        }
+        else
+        {
+            ungetc( c, pFile );
+            while ( 1 )
+            {
+                RetValue = fscanf( pFile, "%d", &Num );
+                assert( RetValue == 1 );
+                if ( Num == 0 )
+                    break;
+                Vec_VecPush( vClauses, i, (void *)Num );
+            }
+            RetValue = fscanf( pFile, "%d", &Num );
+            assert( RetValue == 1 );
+            assert( Num == 0 );
+        }
+    }
+    assert( i-1 == Counter );
+    if ( Vec_IntSize( Vec_VecEntry(vClauses, Counter) ) != 0 )
+        printf( "The last clause is not empty.\n" );
+    else
+        printf( "The empty clause is derived.\n" );
+    Vec_VecFree( vClauses );
+    fclose( pFile );
+}
+
+////////////////////////////////////////////////////////////////////////
+///                       END OF FILE                                ///
+////////////////////////////////////////////////////////////////////////
+
+
diff --git a/src/sat/bsat/satInterA.c b/src/sat/bsat/satInterA.c
index 57628989..5edc5b67 100644
--- a/src/sat/bsat/satInterA.c
+++ b/src/sat/bsat/satInterA.c
@@ -701,6 +701,10 @@ p->timeTrace += clock() - clk;
 //        Inta_ManPrintInterOne( p, pFinal );
     }
     Inta_ManProofSet( p, pFinal, p->Counter );
+    // make sure the same proof ID is not asssigned to two consecutive clauses
+    assert( p->pProofNums[pFinal->Id-1] != p->Counter );
+//    if ( p->pProofNums[pFinal->Id] == p->pProofNums[pFinal->Id-1] )
+//        p->pProofNums[pFinal->Id] = p->pProofNums[pConflict->Id];
     return p->Counter;
 }
 
@@ -748,6 +752,27 @@ int Inta_ManProofRecordOne( Inta_Man_t * p, Sto_Cls_t * pClause )
     {
         assert( 0 ); // cannot prove
         return 0;
+    } 
+
+    // skip the clause if it is weaker or the same as the conflict clause
+    if ( pClause->nLits >= pConflict->nLits )
+    {
+        // check if every literal of conflict clause can be found in the given clause
+        int j;
+        for ( i = 0; i < (int)pConflict->nLits; i++ )
+        {
+            for ( j = 0; j < (int)pClause->nLits; j++ )
+                if ( pConflict->pLits[i] == pClause->pLits[j] )
+                    break;
+            if ( j == (int)pClause->nLits ) // literal pConflict->pLits[i] is not found
+                break;
+        }
+        if ( i == (int)pConflict->nLits ) // all lits are found
+        {
+            // undo to the root level
+            Inta_ManCancelUntil( p, p->nRootSize );
+            return 1;
+        }
     }
 
     // construct the proof
@@ -973,6 +998,7 @@ void * Inta_ManInterpolate( Inta_Man_t * p, Sto_Man_t * pCnf, void * vVarsAB, in
     if ( p->fProofWrite )
     { 
         fclose( p->pFile );
+//        Sat_ProofChecker( "proof.cnf_" );
         p->pFile = NULL;    
     }
 
diff --git a/src/sat/bsat/satInterA_mod.c b/src/sat/bsat/satInterA_mod.c
new file mode 100644
index 00000000..faf396a6
--- /dev/null
+++ b/src/sat/bsat/satInterA_mod.c
@@ -0,0 +1,1104 @@
+/**CFile****************************************************************
+
+  FileName    [satInter.c]
+
+  SystemName  [ABC: Logic synthesis and verification system.]
+
+  PackageName [SAT sat_solver.]
+
+  Synopsis    [Interpolation package.]
+
+  Author      [Alan Mishchenko]
+  
+  Affiliation [UC Berkeley]
+
+  Date        [Ver. 1.0. Started - June 20, 2005.]
+
+  Revision    [$Id: satInter.c,v 1.4 2005/09/16 22:55:03 casem Exp $]
+
+***********************************************************************/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <assert.h>
+#include <time.h>
+#include "satStore.h"
+#include "aig.h"
+
+////////////////////////////////////////////////////////////////////////
+///                        DECLARATIONS                              ///
+////////////////////////////////////////////////////////////////////////
+
+// variable assignments 
+static const lit    LIT_UNDEF = 0xffffffff;
+
+// interpolation manager
+struct Inta_Man_t_
+{
+    // clauses of the problems
+    Sto_Man_t *     pCnf;         // the set of CNF clauses for A and B
+    Vec_Int_t *     vVarsAB;      // the array of global variables
+    // various parameters
+    int             fVerbose;     // verbosiness flag
+    int             fProofVerif;  // verifies the proof
+    int             fProofWrite;  // writes the proof file
+    int             nVarsAlloc;   // the allocated size of var arrays
+    int             nClosAlloc;   // the allocated size of clause arrays
+    // internal BCP
+    int             nRootSize;    // the number of root level assignments
+    int             nTrailSize;   // the number of assignments made 
+    lit *           pTrail;       // chronological order of assignments (size nVars)
+    lit *           pAssigns;     // assignments by variable (size nVars) 
+    char *          pSeens;       // temporary mark (size nVars)
+    Sto_Cls_t **    pReasons;     // reasons for each assignment (size nVars)          
+    Sto_Cls_t **    pWatches;     // watched clauses for each literal (size 2*nVars)          
+    // interpolation data
+    Aig_Man_t *     pAig;         // the AIG manager for recording the interpolant
+    int *           pVarTypes;    // variable type (size nVars) [1=A, 0=B, <0=AB]
+    Aig_Obj_t **    pInters;      // storage for interpolants as truth tables (size nClauses)
+    int             nIntersAlloc; // the allocated size of truth table array
+    // proof recording
+    int             Counter;      // counter of resolved clauses
+    int *           pProofNums;   // the proof numbers for each clause (size nClauses)
+    FILE *          pFile;        // the file for proof recording
+    // internal verification
+    lit *           pResLits;     // the literals of the resolvent   
+    int             nResLits;     // the number of literals of the resolvent
+    int             nResLitsAlloc;// the number of literals of the resolvent
+    // runtime stats
+    int             timeBcp;      // the runtime for BCP
+    int             timeTrace;    // the runtime of trace construction
+    int             timeTotal;    // the total runtime of interpolation
+};
+
+// procedure to get hold of the clauses' truth table 
+static inline Aig_Obj_t ** Inta_ManAigRead( Inta_Man_t * pMan, Sto_Cls_t * pCls )                   { return pMan->pInters + pCls->Id;          }
+static inline void         Inta_ManAigClear( Inta_Man_t * pMan, Aig_Obj_t ** p )                    { *p = Aig_ManConst0(pMan->pAig);           }
+static inline void         Inta_ManAigFill( Inta_Man_t * pMan, Aig_Obj_t ** p )                     { *p = Aig_ManConst1(pMan->pAig);           }
+static inline void         Inta_ManAigCopy( Inta_Man_t * pMan, Aig_Obj_t ** p, Aig_Obj_t ** q )     { *p = *q;                                  }
+static inline void         Inta_ManAigAnd( Inta_Man_t * pMan, Aig_Obj_t ** p, Aig_Obj_t ** q )      { *p = Aig_And(pMan->pAig, *p, *q);         }
+static inline void         Inta_ManAigOr( Inta_Man_t * pMan, Aig_Obj_t ** p, Aig_Obj_t ** q )       { *p = Aig_Or(pMan->pAig, *p, *q);          }
+static inline void         Inta_ManAigOrNot( Inta_Man_t * pMan, Aig_Obj_t ** p, Aig_Obj_t ** q )    { *p = Aig_Or(pMan->pAig, *p, Aig_Not(*q)); }
+static inline void         Inta_ManAigOrVar( Inta_Man_t * pMan, Aig_Obj_t ** p, int v )             { *p = Aig_Or(pMan->pAig, *p, Aig_IthVar(pMan->pAig, v));          }
+static inline void         Inta_ManAigOrNotVar( Inta_Man_t * pMan, Aig_Obj_t ** p, int v )          { *p = Aig_Or(pMan->pAig, *p, Aig_Not(Aig_IthVar(pMan->pAig, v))); }
+
+// reading/writing the proof for a clause
+static inline int          Inta_ManProofGet( Inta_Man_t * p, Sto_Cls_t * pCls )                  { return p->pProofNums[pCls->Id];           }
+static inline void         Inta_ManProofSet( Inta_Man_t * p, Sto_Cls_t * pCls, int n )           { 
+    p->pProofNums[pCls->Id] = n;              
+    if ( pCls->Id == 5552 || pCls->Id == 5553 )
+    {
+        int x = 0;
+    }
+}
+
+////////////////////////////////////////////////////////////////////////
+///                     FUNCTION DEFINITIONS                         ///
+////////////////////////////////////////////////////////////////////////
+
+/**Function*************************************************************
+
+  Synopsis    [Allocate proof manager.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Inta_Man_t * Inta_ManAlloc()
+{
+    Inta_Man_t * p;
+    // allocate the manager
+    p = (Inta_Man_t *)malloc( sizeof(Inta_Man_t) );
+    memset( p, 0, sizeof(Inta_Man_t) );
+    // verification
+    p->nResLitsAlloc = (1<<16);
+    p->pResLits = malloc( sizeof(lit) * p->nResLitsAlloc );
+    // parameters
+    p->fProofWrite = 1;
+    p->fProofVerif = 1;
+
+    return p;    
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Count common variables in the clauses of A and B.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Inta_ManGlobalVars( Inta_Man_t * p )
+{
+    Sto_Cls_t * pClause;
+    int LargeNum = -100000000;
+    int Var, nVarsAB, v;
+
+    // mark the variable encountered in the clauses of A
+    Sto_ManForEachClauseRoot( p->pCnf, pClause )
+    {
+        if ( !pClause->fA )
+            break;
+        for ( v = 0; v < (int)pClause->nLits; v++ )
+            p->pVarTypes[lit_var(pClause->pLits[v])] = 1;
+    }
+
+    // check variables that appear in clauses of B
+    nVarsAB = 0;
+    Sto_ManForEachClauseRoot( p->pCnf, pClause )
+    {
+        if ( pClause->fA )
+            continue;
+        for ( v = 0; v < (int)pClause->nLits; v++ )
+        {
+            Var = lit_var(pClause->pLits[v]);
+            if ( p->pVarTypes[Var] == 1 ) // var of A
+            {
+                // change it into a global variable
+                nVarsAB++;
+                p->pVarTypes[Var] = LargeNum;
+            }
+        }
+    }
+    assert( nVarsAB <= Vec_IntSize(p->vVarsAB) );
+
+    // order global variables
+    nVarsAB = 0;
+    Vec_IntForEachEntry( p->vVarsAB, Var, v )
+        p->pVarTypes[Var] = -(1+nVarsAB++);
+
+    // check that there is no extra global variables
+    for ( v = 0; v < p->pCnf->nVars; v++ )
+        assert( p->pVarTypes[v] != LargeNum );
+    return nVarsAB;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Resize proof manager.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Inta_ManResize( Inta_Man_t * p )
+{
+    // check if resizing is needed
+    if ( p->nVarsAlloc < p->pCnf->nVars )
+    {
+        // find the new size
+        if ( p->nVarsAlloc == 0 )
+            p->nVarsAlloc = 1;
+        while ( p->nVarsAlloc < p->pCnf->nVars ) 
+            p->nVarsAlloc *= 2;
+        // resize the arrays
+        p->pTrail    = (lit *)       realloc( p->pTrail,    sizeof(lit) * p->nVarsAlloc );
+        p->pAssigns  = (lit *)       realloc( p->pAssigns,  sizeof(lit) * p->nVarsAlloc );
+        p->pSeens    = (char *)      realloc( p->pSeens,    sizeof(char) * p->nVarsAlloc );
+        p->pVarTypes = (int *)       realloc( p->pVarTypes, sizeof(int) * p->nVarsAlloc );
+        p->pReasons  = (Sto_Cls_t **)realloc( p->pReasons,  sizeof(Sto_Cls_t *) * p->nVarsAlloc );
+        p->pWatches  = (Sto_Cls_t **)realloc( p->pWatches,  sizeof(Sto_Cls_t *) * p->nVarsAlloc*2 );
+    }
+
+    // clean the free space
+    memset( p->pAssigns , 0xff, sizeof(lit) * p->pCnf->nVars );
+    memset( p->pSeens   , 0,    sizeof(char) * p->pCnf->nVars );
+    memset( p->pVarTypes, 0,    sizeof(int) * p->pCnf->nVars );
+    memset( p->pReasons , 0,    sizeof(Sto_Cls_t *) * p->pCnf->nVars );
+    memset( p->pWatches , 0,    sizeof(Sto_Cls_t *) * p->pCnf->nVars*2 );
+
+    // compute the number of common variables
+    Inta_ManGlobalVars( p );
+
+    // check if resizing of clauses is needed
+    if ( p->nClosAlloc < p->pCnf->nClauses )
+    {
+        // find the new size
+        if ( p->nClosAlloc == 0 )
+            p->nClosAlloc = 1;
+        while ( p->nClosAlloc < p->pCnf->nClauses ) 
+            p->nClosAlloc *= 2;
+        // resize the arrays
+        p->pProofNums = (int *) realloc( p->pProofNums,  sizeof(int) * p->nClosAlloc );
+    }
+    memset( p->pProofNums, 0, sizeof(int) * p->pCnf->nClauses );
+
+    // check if resizing of truth tables is needed
+    if ( p->nIntersAlloc < p->pCnf->nClauses )
+    {
+        p->nIntersAlloc = p->pCnf->nClauses;
+        p->pInters = (Aig_Obj_t **) realloc( p->pInters, sizeof(Aig_Obj_t *) * p->nIntersAlloc );
+    }
+    memset( p->pInters, 0, sizeof(Aig_Obj_t *) * p->pCnf->nClauses );
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Deallocate proof manager.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Inta_ManFree( Inta_Man_t * p )
+{
+/*
+    printf( "Runtime stats:\n" );
+PRT( "BCP     ", p->timeBcp   );
+PRT( "Trace   ", p->timeTrace );
+PRT( "TOTAL   ", p->timeTotal );
+*/
+    free( p->pInters );
+    free( p->pProofNums );
+    free( p->pTrail );
+    free( p->pAssigns );
+    free( p->pSeens );
+    free( p->pVarTypes );
+    free( p->pReasons );
+    free( p->pWatches );
+    free( p->pResLits );
+    free( p );
+}
+
+
+
+
+/**Function*************************************************************
+
+  Synopsis    [Prints the clause.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Inta_ManPrintClause( Inta_Man_t * p, Sto_Cls_t * pClause )
+{
+    int i;
+    printf( "Clause ID = %d. Proof = %d. {", pClause->Id, Inta_ManProofGet(p, pClause) );
+    for ( i = 0; i < (int)pClause->nLits; i++ )
+        printf( " %d", pClause->pLits[i] );
+    printf( " }\n" );
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Prints the resolvent.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Inta_ManPrintResolvent( lit * pResLits, int nResLits )
+{
+    int i;
+    printf( "Resolvent: {" );
+    for ( i = 0; i < nResLits; i++ )
+        // Yu Hu
+        // printf( " %d", pResLits[i] );
+        printf( " %d", lit_print(pResLits[i]) );
+    printf( " }\n" );
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Prints the interpolant for one clause.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Inta_ManPrintInterOne( Inta_Man_t * p, Sto_Cls_t * pClause )
+{
+    printf( "Clause %2d :  ", pClause->Id );
+//    Extra_PrintBinary___( stdout, Inta_ManAigRead(p, pClause), (1 << p->nVarsAB) );
+    printf( "\n" );
+}
+
+
+
+/**Function*************************************************************
+
+  Synopsis    [Adds one clause to the watcher list.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+static inline void Inta_ManWatchClause( Inta_Man_t * p, Sto_Cls_t * pClause, lit Lit )
+{
+    assert( lit_check(Lit, p->pCnf->nVars) );
+    if ( pClause->pLits[0] == Lit )
+        pClause->pNext0 = p->pWatches[lit_neg(Lit)];  
+    else
+    {
+        assert( pClause->pLits[1] == Lit );
+        pClause->pNext1 = p->pWatches[lit_neg(Lit)];  
+    }
+    p->pWatches[lit_neg(Lit)] = pClause;
+}
+
+
+/**Function*************************************************************
+
+  Synopsis    [Records implication.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+static inline int Inta_ManEnqueue( Inta_Man_t * p, lit Lit, Sto_Cls_t * pReason )
+{
+    int Var = lit_var(Lit);
+    if ( p->pAssigns[Var] != LIT_UNDEF )
+        return p->pAssigns[Var] == Lit;
+    p->pAssigns[Var] = Lit;
+    p->pReasons[Var] = pReason;
+    p->pTrail[p->nTrailSize++] = Lit;
+//printf( "assigning var %d value %d\n", Var, !lit_sign(Lit) );
+    return 1;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Records implication.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+static inline void Inta_ManCancelUntil( Inta_Man_t * p, int Level )
+{
+    lit Lit;
+    int i, Var;
+    for ( i = p->nTrailSize - 1; i >= Level; i-- )
+    {
+        Lit = p->pTrail[i];
+        Var = lit_var( Lit );
+        p->pReasons[Var] = NULL;
+        p->pAssigns[Var] = LIT_UNDEF;
+//printf( "cancelling var %d\n", Var );
+    }
+    p->nTrailSize = Level;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Propagate one assignment.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+static inline Sto_Cls_t * Inta_ManPropagateOne( Inta_Man_t * p, lit Lit )
+{
+    Sto_Cls_t ** ppPrev, * pCur, * pTemp;
+    lit LitF = lit_neg(Lit);
+    int i;
+    // iterate through the literals
+    ppPrev = p->pWatches + Lit;
+    for ( pCur = p->pWatches[Lit]; pCur; pCur = *ppPrev )
+    {
+        // make sure the false literal is in the second literal of the clause
+        if ( pCur->pLits[0] == LitF )
+        {
+            pCur->pLits[0] = pCur->pLits[1];
+            pCur->pLits[1] = LitF;
+            pTemp = pCur->pNext0;
+            pCur->pNext0 = pCur->pNext1;
+            pCur->pNext1 = pTemp;
+        }
+        assert( pCur->pLits[1] == LitF );
+
+        // if the first literal is true, the clause is satisfied
+        if ( pCur->pLits[0] == p->pAssigns[lit_var(pCur->pLits[0])] )
+        {
+            ppPrev = &pCur->pNext1;
+            continue;
+        }
+
+        // look for a new literal to watch
+        for ( i = 2; i < (int)pCur->nLits; i++ )
+        {
+            // skip the case when the literal is false
+            if ( lit_neg(pCur->pLits[i]) == p->pAssigns[lit_var(pCur->pLits[i])] )
+                continue;
+            // the literal is either true or unassigned - watch it
+            pCur->pLits[1] = pCur->pLits[i];
+            pCur->pLits[i] = LitF;
+            // remove this clause from the watch list of Lit
+            *ppPrev = pCur->pNext1;
+            // add this clause to the watch list of pCur->pLits[i] (now it is pCur->pLits[1])
+            Inta_ManWatchClause( p, pCur, pCur->pLits[1] );
+            break;
+        }
+        if ( i < (int)pCur->nLits ) // found new watch
+            continue;
+
+        // clause is unit - enqueue new implication
+        if ( Inta_ManEnqueue(p, pCur->pLits[0], pCur) )
+        {
+            ppPrev = &pCur->pNext1;
+            continue;
+        }
+
+        // conflict detected - return the conflict clause
+        return pCur;
+    }
+    return NULL;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Propagate the current assignments.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Sto_Cls_t * Inta_ManPropagate( Inta_Man_t * p, int Start )
+{
+    Sto_Cls_t * pClause;
+    int i;
+    int clk = clock();
+    for ( i = Start; i < p->nTrailSize; i++ )
+    {
+        pClause = Inta_ManPropagateOne( p, p->pTrail[i] );
+        if ( pClause )
+        {
+p->timeBcp += clock() - clk;
+            return pClause;
+        }
+    }
+p->timeBcp += clock() - clk;
+    return NULL;
+}
+
+
+/**Function*************************************************************
+
+  Synopsis    [Writes one root clause into a file.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Inta_ManProofWriteOne( Inta_Man_t * p, Sto_Cls_t * pClause )
+{
+    Inta_ManProofSet( p, pClause, ++p->Counter );
+
+    if ( p->fProofWrite )
+    {
+        int v;
+        fprintf( p->pFile, "%d", Inta_ManProofGet(p, pClause) );
+        for ( v = 0; v < (int)pClause->nLits; v++ )
+            fprintf( p->pFile, " %d", lit_print(pClause->pLits[v]) );
+        fprintf( p->pFile, " 0 0\n" );
+    }
+}
+
+// Yu Hu
+void Inta_ManPrintClauseEx( lit * pResLits, int nResLits )
+{
+    int i;
+    printf( " {" );
+    for ( i = 0; i < nResLits; i++ )
+        printf( " %d", lit_print(pResLits[i]) );
+    printf( " }\n" );
+}
+
+
+/**Function*************************************************************
+
+  Synopsis    [Traces the proof for one clause.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Inta_ManProofTraceOne( Inta_Man_t * p, Sto_Cls_t * pConflict, Sto_Cls_t * pFinal )
+{
+    Sto_Cls_t * pReason;
+    int i, v, Var, PrevId;
+    int fPrint = 1; // Yu Hu
+    int clk = clock();
+
+    // collect resolvent literals
+    if ( p->fProofVerif )
+    {
+        assert( (int)pConflict->nLits <= p->nResLitsAlloc );
+        memcpy( p->pResLits, pConflict->pLits, sizeof(lit) * pConflict->nLits );
+        p->nResLits = pConflict->nLits;
+    }
+
+    // mark all the variables in the conflict as seen
+    for ( v = 0; v < (int)pConflict->nLits; v++ )
+        p->pSeens[lit_var(pConflict->pLits[v])] = 1;
+
+    // start the anticedents
+//    pFinal->pAntis = Vec_PtrAlloc( 32 );
+//    Vec_PtrPush( pFinal->pAntis, pConflict );
+
+    if ( p->pCnf->nClausesA )
+        Inta_ManAigCopy( p, Inta_ManAigRead(p, pFinal), Inta_ManAigRead(p, pConflict) );
+
+    // follow the trail backwards
+    PrevId = Inta_ManProofGet(p, pConflict);
+    for ( i = p->nTrailSize - 1; i >= 0; i-- )
+    {
+        // skip literals that are not involved
+        Var = lit_var(p->pTrail[i]);
+        if ( !p->pSeens[Var] )
+            continue;
+        p->pSeens[Var] = 0;
+
+        // skip literals of the resulting clause
+        pReason = p->pReasons[Var];
+        if ( pReason == NULL )
+            continue;
+        assert( p->pTrail[i] == pReason->pLits[0] );
+
+        // add the variables to seen
+        for ( v = 1; v < (int)pReason->nLits; v++ )
+            p->pSeens[lit_var(pReason->pLits[v])] = 1;
+
+        // record the reason clause
+        assert( Inta_ManProofGet(p, pReason) > 0 );
+        p->Counter++;
+        if ( p->fProofWrite && p->Counter >= 8370 &&  p->Counter <= 8380 ) {
+            fprintf( p->pFile, "%d * %d %d 0\n", p->Counter, PrevId, Inta_ManProofGet(p, pReason) );
+            // Yu Hu
+            printf( "%d * %d %d 0\n", p->Counter, PrevId, Inta_ManProofGet(p, pReason) );
+
+            if ( p->Counter == 8371 )
+            {
+                int s = 0;
+            }
+        }
+        PrevId = p->Counter;
+
+        if ( p->pCnf->nClausesA )
+        {
+            if ( p->pVarTypes[Var] == 1 ) // var of A
+                Inta_ManAigOr( p, Inta_ManAigRead(p, pFinal), Inta_ManAigRead(p, pReason) );
+            else
+                Inta_ManAigAnd( p, Inta_ManAigRead(p, pFinal), Inta_ManAigRead(p, pReason) );
+        }
+ 
+        // resolve the temporary resolvent with the reason clause
+        if ( p->fProofVerif )
+        {
+            int v1, v2; 
+
+            // Yu Hu
+            // if ( fPrint )
+            //     Inta_ManPrintResolvent( p->pResLits, p->nResLits );
+            if ( fPrint && p->Counter >= 8370 &&  p->Counter <= 8380 ) {                                                                                                
+                printf("pivot = %d,\n", lit_print(p->pTrail[i]));                                                          
+                Inta_ManPrintClauseEx( p->pResLits, p->nResLits);                                                          
+            }                                                          
+
+            // check that the var is present in the resolvent
+            for ( v1 = 0; v1 < p->nResLits; v1++ )
+                if ( lit_var(p->pResLits[v1]) == Var )
+                    break;
+            if ( v1 == p->nResLits )
+                printf( "Recording clause %d: Cannot find variable %d in the temporary resolvent.\n", pFinal->Id, Var );
+            if ( p->pResLits[v1] != lit_neg(pReason->pLits[0]) )
+                printf( "Recording clause %d: The resolved variable %d is in the wrong polarity.\n", pFinal->Id, Var );
+            // remove this variable from the resolvent
+            assert( lit_var(p->pResLits[v1]) == Var );
+            p->nResLits--;
+            for ( ; v1 < p->nResLits; v1++ )
+                p->pResLits[v1] = p->pResLits[v1+1];
+            // add variables of the reason clause
+            for ( v2 = 1; v2 < (int)pReason->nLits; v2++ )
+            {
+                for ( v1 = 0; v1 < p->nResLits; v1++ )
+                    if ( lit_var(p->pResLits[v1]) == lit_var(pReason->pLits[v2]) )
+                        break;
+                // if it is a new variable, add it to the resolvent
+                if ( v1 == p->nResLits ) 
+                {
+                    if ( p->nResLits == p->nResLitsAlloc )
+                        printf( "Recording clause %d: Ran out of space for intermediate resolvent.\n", pFinal->Id );
+                    p->pResLits[ p->nResLits++ ] = pReason->pLits[v2];
+                    continue;
+                }
+                // if the variable is the same, the literal should be the same too
+                if ( p->pResLits[v1] == pReason->pLits[v2] )
+                    continue;
+                // the literal is different
+                printf( "Recording clause %d: Trying to resolve the clause with more than one opposite literal.\n", pFinal->Id );
+            }
+
+            // Yu Hu
+            if ( fPrint && p->Counter >= 8370 &&  p->Counter <= 8380 ) {                                                                                                
+                Inta_ManPrintClauseEx( pReason->pLits, pReason->nLits);                                                    
+                Inta_ManPrintResolvent( p->pResLits, p->nResLits);                                                        
+            }            
+
+        }
+//        Vec_PtrPush( pFinal->pAntis, pReason );
+    }
+
+    // unmark all seen variables
+//    for ( i = p->nTrailSize - 1; i >= 0; i-- )
+//        p->pSeens[lit_var(p->pTrail[i])] = 0;
+    // check that the literals are unmarked
+//    for ( i = p->nTrailSize - 1; i >= 0; i-- )
+//        assert( p->pSeens[lit_var(p->pTrail[i])] == 0 );
+
+    // use the resulting clause to check the correctness of resolution
+    if ( p->fProofVerif )
+    {
+        int v1, v2; 
+
+        // Yu Hu
+//        if ( fPrint )
+//            Inta_ManPrintResolvent( p->pResLits, p->nResLits );
+
+        for ( v1 = 0; v1 < p->nResLits; v1++ )
+        {
+            for ( v2 = 0; v2 < (int)pFinal->nLits; v2++ )
+                if ( pFinal->pLits[v2] == p->pResLits[v1] )
+                    break;
+            if ( v2 < (int)pFinal->nLits )
+                continue;
+            break;
+        }
+        if ( v1 < p->nResLits )
+        {
+            printf( "Recording clause %d: The final resolvent is wrong.\n", pFinal->Id );
+            Inta_ManPrintClause( p, pConflict );
+            Inta_ManPrintResolvent( p->pResLits, p->nResLits );
+            Inta_ManPrintClause( p, pFinal );
+        }
+
+        // if there are literals in the clause that are not in the resolvent
+        // it means that the derived resolvent is stronger than the clause
+        // we can replace the clause with the resolvent by removing these literals
+        if ( p->nResLits != (int)pFinal->nLits )
+        {
+            for ( v1 = 0; v1 < (int)pFinal->nLits; v1++ )
+            {
+                for ( v2 = 0; v2 < p->nResLits; v2++ )
+                    if ( pFinal->pLits[v1] == p->pResLits[v2] )
+                        break;
+                if ( v2 < p->nResLits )
+                    continue;
+                // remove literal v1 from the final clause
+                pFinal->nLits--;
+                for ( v2 = v1; v2 < (int)pFinal->nLits; v2++ )
+                    pFinal->pLits[v2] = pFinal->pLits[v2+1];
+                v1--;
+            }
+            assert( p->nResLits == (int)pFinal->nLits );
+        }
+    }
+p->timeTrace += clock() - clk;  
+
+    // return the proof pointer 
+    if ( p->pCnf->nClausesA )
+    {
+//        Inta_ManPrintInterOne( p, pFinal );
+    }
+    Inta_ManProofSet( p, pFinal, p->Counter );
+    if ( pFinal->Id == 5552 || pFinal->Id == 5553 )
+    {
+        int x = 0;
+    }
+
+    if ( p->pProofNums[pFinal->Id] == p->pProofNums[pFinal->Id-1] )
+        p->pProofNums[pFinal->Id] = p->pProofNums[pConflict->Id];
+
+    return p->Counter;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Records the proof for one clause.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Inta_ManProofRecordOne( Inta_Man_t * p, Sto_Cls_t * pClause )
+{
+    Sto_Cls_t * pConflict;
+    int i;
+
+    // empty clause never ends up there
+    assert( pClause->nLits > 0 );
+    if ( pClause->nLits == 0 )
+        printf( "Error: Empty clause is attempted.\n" );
+
+    assert( !pClause->fRoot );
+    assert( p->nTrailSize == p->nRootSize );
+
+    // if any of the clause literals are already assumed
+    // it means that the clause is redundant and can be skipped
+    for ( i = 0; i < (int)pClause->nLits; i++ )
+        if ( p->pAssigns[lit_var(pClause->pLits[i])] == pClause->pLits[i] )
+            return 1;
+
+    // add assumptions to the trail
+    for ( i = 0; i < (int)pClause->nLits; i++ )
+        if ( !Inta_ManEnqueue( p, lit_neg(pClause->pLits[i]), NULL ) )
+        {
+            assert( 0 ); // impossible
+            return 0;
+        }
+
+    // propagate the assumptions
+    pConflict = Inta_ManPropagate( p, p->nRootSize );
+    if ( pConflict == NULL )
+    {
+        assert( 0 ); // cannot prove
+        return 0;
+    }
+
+    // construct the proof
+    Inta_ManProofTraceOne( p, pConflict, pClause );
+
+    // undo to the root level
+    Inta_ManCancelUntil( p, p->nRootSize );
+
+    // add large clauses to the watched lists
+    if ( pClause->nLits > 1 )
+    {
+        Inta_ManWatchClause( p, pClause, pClause->pLits[0] );
+        Inta_ManWatchClause( p, pClause, pClause->pLits[1] );
+        return 1;
+    }
+    assert( pClause->nLits == 1 );
+
+    // if the clause proved is unit, add it and propagate
+    if ( !Inta_ManEnqueue( p, pClause->pLits[0], pClause ) )
+    {
+        assert( 0 ); // impossible
+        return 0;
+    }
+
+    // propagate the assumption
+    pConflict = Inta_ManPropagate( p, p->nRootSize );
+    if ( pConflict )
+    {
+        // construct the proof
+        Inta_ManProofTraceOne( p, pConflict, p->pCnf->pEmpty );
+//        if ( p->fVerbose )
+//            printf( "Found last conflict after adding unit clause number %d!\n", pClause->Id );
+        return 0;
+    }
+
+    // update the root level
+    p->nRootSize = p->nTrailSize;
+    return 1;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Propagate the root clauses.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Inta_ManProcessRoots( Inta_Man_t * p )
+{
+    Sto_Cls_t * pClause;
+    int Counter;
+
+    // make sure the root clauses are preceeding the learnt clauses
+    Counter = 0;
+    Sto_ManForEachClause( p->pCnf, pClause )
+    {
+        assert( (int)pClause->fA    == (Counter < (int)p->pCnf->nClausesA) );
+        assert( (int)pClause->fRoot == (Counter < (int)p->pCnf->nRoots)    );
+        Counter++;
+    }
+    assert( p->pCnf->nClauses == Counter );
+
+    // make sure the last clause if empty
+    assert( p->pCnf->pTail->nLits == 0 );
+
+    // go through the root unit clauses
+    p->nTrailSize = 0;
+    Sto_ManForEachClauseRoot( p->pCnf, pClause )
+    {
+        // create watcher lists for the root clauses
+        if ( pClause->nLits > 1 )
+        {
+            Inta_ManWatchClause( p, pClause, pClause->pLits[0] );
+            Inta_ManWatchClause( p, pClause, pClause->pLits[1] );
+        }
+        // empty clause and large clauses
+        if ( pClause->nLits != 1 )
+            continue;
+        // unit clause
+        assert( lit_check(pClause->pLits[0], p->pCnf->nVars) );
+        if ( !Inta_ManEnqueue( p, pClause->pLits[0], pClause ) )
+        {
+            // detected root level conflict
+//            printf( "Error in Inta_ManProcessRoots(): Detected a root-level conflict too early!\n" );
+//            assert( 0 );
+            // detected root level conflict
+            Inta_ManProofTraceOne( p, pClause, p->pCnf->pEmpty );
+            if ( p->fVerbose )
+                printf( "Found root level conflict!\n" );
+            return 0;
+        }
+    }
+
+    // propagate the root unit clauses
+    pClause = Inta_ManPropagate( p, 0 );
+    if ( pClause )
+    {
+        // detected root level conflict
+        Inta_ManProofTraceOne( p, pClause, p->pCnf->pEmpty );
+        if ( p->fVerbose )
+            printf( "Found root level conflict!\n" );
+        return 0;
+    }
+
+    // set the root level
+    p->nRootSize = p->nTrailSize;
+    return 1;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Records the proof.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Inta_ManPrepareInter( Inta_Man_t * p )
+{
+    Sto_Cls_t * pClause;
+    int Var, VarAB, v;
+
+    // set interpolants for root clauses
+    Sto_ManForEachClauseRoot( p->pCnf, pClause )
+    {
+        if ( !pClause->fA ) // clause of B
+        {
+            Inta_ManAigFill( p, Inta_ManAigRead(p, pClause) );
+//            Inta_ManPrintInterOne( p, pClause );
+            continue;
+        }
+        // clause of A
+        Inta_ManAigClear( p, Inta_ManAigRead(p, pClause) );
+        for ( v = 0; v < (int)pClause->nLits; v++ )
+        {
+            Var = lit_var(pClause->pLits[v]);
+            if ( p->pVarTypes[Var] < 0 ) // global var
+            {
+                VarAB = -p->pVarTypes[Var]-1;
+                assert( VarAB >= 0 && VarAB < Vec_IntSize(p->vVarsAB) );
+                if ( lit_sign(pClause->pLits[v]) ) // negative var
+                    Inta_ManAigOrNotVar( p, Inta_ManAigRead(p, pClause), VarAB );
+                else
+                    Inta_ManAigOrVar( p, Inta_ManAigRead(p, pClause), VarAB );
+            }
+        }
+//        Inta_ManPrintInterOne( p, pClause );
+    }
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Computes interpolant for the given CNF.]
+
+  Description [Takes the interpolation manager, the CNF deriving by the SAT
+  solver, which includes ClausesA, ClausesB, and learned clauses. Additional
+  arguments are the vector of variables common to AB and the verbosiness flag.
+  Returns the AIG manager with a single output, containing the interpolant.]
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void * Inta_ManInterpolate( Inta_Man_t * p, Sto_Man_t * pCnf, void * vVarsAB, int fVerbose )
+{
+    Aig_Man_t * pRes;
+    Aig_Obj_t * pObj;
+    Sto_Cls_t * pClause;
+    int RetValue = 1;
+    int clkTotal = clock();
+
+    // check that the CNF makes sense
+    assert( pCnf->nVars > 0 && pCnf->nClauses > 0 );
+    p->pCnf = pCnf;
+    p->fVerbose = fVerbose;
+    p->vVarsAB = vVarsAB;
+    p->pAig = pRes = Aig_ManStart( 10000 );
+    Aig_IthVar( p->pAig, Vec_IntSize(p->vVarsAB) - 1 );
+
+    // adjust the manager
+    Inta_ManResize( p );
+
+    // prepare the interpolant computation
+    Inta_ManPrepareInter( p );
+
+    // construct proof for each clause
+    // start the proof
+    if ( p->fProofWrite )
+    {
+        p->pFile = fopen( "proof.cnf_", "w" );
+        p->Counter = 0;
+    }
+
+    // write the root clauses
+    Sto_ManForEachClauseRoot( p->pCnf, pClause )
+        Inta_ManProofWriteOne( p, pClause );
+
+    // propagate root level assignments
+    if ( Inta_ManProcessRoots( p ) )
+    {
+        // if there is no conflict, consider learned clauses
+        Sto_ManForEachClause( p->pCnf, pClause )
+        {
+            if ( pClause->Id == 5552 )
+            {
+                int s = 0;
+            }
+            if ( pClause->fRoot )
+                continue;
+            if ( !Inta_ManProofRecordOne( p, pClause ) )
+            {
+                RetValue = 0;
+                break;
+            }
+        }
+    }
+
+    // stop the proof
+    if ( p->fProofWrite )
+    { 
+        fclose( p->pFile );
+        p->pFile = NULL;    
+    }
+
+    if ( fVerbose )
+    {
+//        PRT( "Interpo", clock() - clkTotal );
+    printf( "Vars = %d. Roots = %d. Learned = %d. Resol steps = %d.  Ave = %.2f.  Mem = %.2f Mb\n", 
+        p->pCnf->nVars, p->pCnf->nRoots, p->pCnf->nClauses-p->pCnf->nRoots, p->Counter,  
+        1.0*(p->Counter-p->pCnf->nRoots)/(p->pCnf->nClauses-p->pCnf->nRoots), 
+        1.0*Sto_ManMemoryReport(p->pCnf)/(1<<20) );
+p->timeTotal += clock() - clkTotal;
+    }
+
+    pObj = *Inta_ManAigRead( p, p->pCnf->pTail );
+    Aig_ObjCreatePo( pRes, pObj );
+    Aig_ManCleanup( pRes );
+
+    p->pAig = NULL;
+    return pRes;
+    
+}
+
+
+/**Function*************************************************************
+
+  Synopsis    []
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Aig_Man_t * Inta_ManDeriveClauses( Inta_Man_t * pMan, Sto_Man_t * pCnf, int fClausesA )
+{
+    Aig_Man_t * p;
+    Aig_Obj_t * pMiter, * pSum, * pLit;
+    Sto_Cls_t * pClause;
+    int Var, VarAB, v;
+    p = Aig_ManStart( 10000 );
+    pMiter = Aig_ManConst1(p);
+    Sto_ManForEachClauseRoot( pCnf, pClause )
+    {
+        if ( fClausesA ^ pClause->fA ) // clause of B
+            continue;
+        // clause of A
+        pSum = Aig_ManConst0(p);
+        for ( v = 0; v < (int)pClause->nLits; v++ )
+        {
+            Var = lit_var(pClause->pLits[v]);
+            if ( pMan->pVarTypes[Var] < 0 ) // global var
+            {
+                VarAB = -pMan->pVarTypes[Var]-1;
+                assert( VarAB >= 0 && VarAB < Vec_IntSize(pMan->vVarsAB) );
+                pLit = Aig_NotCond( Aig_IthVar(p, VarAB), lit_sign(pClause->pLits[v]) );
+            }
+            else
+                pLit = Aig_NotCond( Aig_IthVar(p, Vec_IntSize(pMan->vVarsAB)+1+Var), lit_sign(pClause->pLits[v]) );
+            pSum = Aig_Or( p, pSum, pLit );
+        }
+        pMiter = Aig_And( p, pMiter, pSum );
+    }
+    Aig_ObjCreatePo( p, pMiter );
+    return p;
+}
+
+////////////////////////////////////////////////////////////////////////
+///                       END OF FILE                                ///
+////////////////////////////////////////////////////////////////////////
+
+
diff --git a/src/sat/bsat/satInterA_old.c b/src/sat/bsat/satInterA_old.c
new file mode 100644
index 00000000..57628989
--- /dev/null
+++ b/src/sat/bsat/satInterA_old.c
@@ -0,0 +1,1047 @@
+/**CFile****************************************************************
+
+  FileName    [satInter.c]
+
+  SystemName  [ABC: Logic synthesis and verification system.]
+
+  PackageName [SAT sat_solver.]
+
+  Synopsis    [Interpolation package.]
+
+  Author      [Alan Mishchenko]
+  
+  Affiliation [UC Berkeley]
+
+  Date        [Ver. 1.0. Started - June 20, 2005.]
+
+  Revision    [$Id: satInter.c,v 1.4 2005/09/16 22:55:03 casem Exp $]
+
+***********************************************************************/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <assert.h>
+#include <time.h>
+#include "satStore.h"
+#include "aig.h"
+
+////////////////////////////////////////////////////////////////////////
+///                        DECLARATIONS                              ///
+////////////////////////////////////////////////////////////////////////
+
+// variable assignments 
+static const lit    LIT_UNDEF = 0xffffffff;
+
+// interpolation manager
+struct Inta_Man_t_
+{
+    // clauses of the problems
+    Sto_Man_t *     pCnf;         // the set of CNF clauses for A and B
+    Vec_Int_t *     vVarsAB;      // the array of global variables
+    // various parameters
+    int             fVerbose;     // verbosiness flag
+    int             fProofVerif;  // verifies the proof
+    int             fProofWrite;  // writes the proof file
+    int             nVarsAlloc;   // the allocated size of var arrays
+    int             nClosAlloc;   // the allocated size of clause arrays
+    // internal BCP
+    int             nRootSize;    // the number of root level assignments
+    int             nTrailSize;   // the number of assignments made 
+    lit *           pTrail;       // chronological order of assignments (size nVars)
+    lit *           pAssigns;     // assignments by variable (size nVars) 
+    char *          pSeens;       // temporary mark (size nVars)
+    Sto_Cls_t **    pReasons;     // reasons for each assignment (size nVars)          
+    Sto_Cls_t **    pWatches;     // watched clauses for each literal (size 2*nVars)          
+    // interpolation data
+    Aig_Man_t *     pAig;         // the AIG manager for recording the interpolant
+    int *           pVarTypes;    // variable type (size nVars) [1=A, 0=B, <0=AB]
+    Aig_Obj_t **    pInters;      // storage for interpolants as truth tables (size nClauses)
+    int             nIntersAlloc; // the allocated size of truth table array
+    // proof recording
+    int             Counter;      // counter of resolved clauses
+    int *           pProofNums;   // the proof numbers for each clause (size nClauses)
+    FILE *          pFile;        // the file for proof recording
+    // internal verification
+    lit *           pResLits;     // the literals of the resolvent   
+    int             nResLits;     // the number of literals of the resolvent
+    int             nResLitsAlloc;// the number of literals of the resolvent
+    // runtime stats
+    int             timeBcp;      // the runtime for BCP
+    int             timeTrace;    // the runtime of trace construction
+    int             timeTotal;    // the total runtime of interpolation
+};
+
+// procedure to get hold of the clauses' truth table 
+static inline Aig_Obj_t ** Inta_ManAigRead( Inta_Man_t * pMan, Sto_Cls_t * pCls )                   { return pMan->pInters + pCls->Id;          }
+static inline void         Inta_ManAigClear( Inta_Man_t * pMan, Aig_Obj_t ** p )                    { *p = Aig_ManConst0(pMan->pAig);           }
+static inline void         Inta_ManAigFill( Inta_Man_t * pMan, Aig_Obj_t ** p )                     { *p = Aig_ManConst1(pMan->pAig);           }
+static inline void         Inta_ManAigCopy( Inta_Man_t * pMan, Aig_Obj_t ** p, Aig_Obj_t ** q )     { *p = *q;                                  }
+static inline void         Inta_ManAigAnd( Inta_Man_t * pMan, Aig_Obj_t ** p, Aig_Obj_t ** q )      { *p = Aig_And(pMan->pAig, *p, *q);         }
+static inline void         Inta_ManAigOr( Inta_Man_t * pMan, Aig_Obj_t ** p, Aig_Obj_t ** q )       { *p = Aig_Or(pMan->pAig, *p, *q);          }
+static inline void         Inta_ManAigOrNot( Inta_Man_t * pMan, Aig_Obj_t ** p, Aig_Obj_t ** q )    { *p = Aig_Or(pMan->pAig, *p, Aig_Not(*q)); }
+static inline void         Inta_ManAigOrVar( Inta_Man_t * pMan, Aig_Obj_t ** p, int v )             { *p = Aig_Or(pMan->pAig, *p, Aig_IthVar(pMan->pAig, v));          }
+static inline void         Inta_ManAigOrNotVar( Inta_Man_t * pMan, Aig_Obj_t ** p, int v )          { *p = Aig_Or(pMan->pAig, *p, Aig_Not(Aig_IthVar(pMan->pAig, v))); }
+
+// reading/writing the proof for a clause
+static inline int          Inta_ManProofGet( Inta_Man_t * p, Sto_Cls_t * pCls )                  { return p->pProofNums[pCls->Id];           }
+static inline void         Inta_ManProofSet( Inta_Man_t * p, Sto_Cls_t * pCls, int n )           { p->pProofNums[pCls->Id] = n;              }
+
+////////////////////////////////////////////////////////////////////////
+///                     FUNCTION DEFINITIONS                         ///
+////////////////////////////////////////////////////////////////////////
+
+/**Function*************************************************************
+
+  Synopsis    [Allocate proof manager.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Inta_Man_t * Inta_ManAlloc()
+{
+    Inta_Man_t * p;
+    // allocate the manager
+    p = (Inta_Man_t *)malloc( sizeof(Inta_Man_t) );
+    memset( p, 0, sizeof(Inta_Man_t) );
+    // verification
+    p->nResLitsAlloc = (1<<16);
+    p->pResLits = malloc( sizeof(lit) * p->nResLitsAlloc );
+    // parameters
+    p->fProofWrite = 0;
+    p->fProofVerif = 1;
+    return p;    
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Count common variables in the clauses of A and B.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Inta_ManGlobalVars( Inta_Man_t * p )
+{
+    Sto_Cls_t * pClause;
+    int LargeNum = -100000000;
+    int Var, nVarsAB, v;
+
+    // mark the variable encountered in the clauses of A
+    Sto_ManForEachClauseRoot( p->pCnf, pClause )
+    {
+        if ( !pClause->fA )
+            break;
+        for ( v = 0; v < (int)pClause->nLits; v++ )
+            p->pVarTypes[lit_var(pClause->pLits[v])] = 1;
+    }
+
+    // check variables that appear in clauses of B
+    nVarsAB = 0;
+    Sto_ManForEachClauseRoot( p->pCnf, pClause )
+    {
+        if ( pClause->fA )
+            continue;
+        for ( v = 0; v < (int)pClause->nLits; v++ )
+        {
+            Var = lit_var(pClause->pLits[v]);
+            if ( p->pVarTypes[Var] == 1 ) // var of A
+            {
+                // change it into a global variable
+                nVarsAB++;
+                p->pVarTypes[Var] = LargeNum;
+            }
+        }
+    }
+    assert( nVarsAB <= Vec_IntSize(p->vVarsAB) );
+
+    // order global variables
+    nVarsAB = 0;
+    Vec_IntForEachEntry( p->vVarsAB, Var, v )
+        p->pVarTypes[Var] = -(1+nVarsAB++);
+
+    // check that there is no extra global variables
+    for ( v = 0; v < p->pCnf->nVars; v++ )
+        assert( p->pVarTypes[v] != LargeNum );
+    return nVarsAB;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Resize proof manager.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Inta_ManResize( Inta_Man_t * p )
+{
+    // check if resizing is needed
+    if ( p->nVarsAlloc < p->pCnf->nVars )
+    {
+        // find the new size
+        if ( p->nVarsAlloc == 0 )
+            p->nVarsAlloc = 1;
+        while ( p->nVarsAlloc < p->pCnf->nVars ) 
+            p->nVarsAlloc *= 2;
+        // resize the arrays
+        p->pTrail    = (lit *)       realloc( p->pTrail,    sizeof(lit) * p->nVarsAlloc );
+        p->pAssigns  = (lit *)       realloc( p->pAssigns,  sizeof(lit) * p->nVarsAlloc );
+        p->pSeens    = (char *)      realloc( p->pSeens,    sizeof(char) * p->nVarsAlloc );
+        p->pVarTypes = (int *)       realloc( p->pVarTypes, sizeof(int) * p->nVarsAlloc );
+        p->pReasons  = (Sto_Cls_t **)realloc( p->pReasons,  sizeof(Sto_Cls_t *) * p->nVarsAlloc );
+        p->pWatches  = (Sto_Cls_t **)realloc( p->pWatches,  sizeof(Sto_Cls_t *) * p->nVarsAlloc*2 );
+    }
+
+    // clean the free space
+    memset( p->pAssigns , 0xff, sizeof(lit) * p->pCnf->nVars );
+    memset( p->pSeens   , 0,    sizeof(char) * p->pCnf->nVars );
+    memset( p->pVarTypes, 0,    sizeof(int) * p->pCnf->nVars );
+    memset( p->pReasons , 0,    sizeof(Sto_Cls_t *) * p->pCnf->nVars );
+    memset( p->pWatches , 0,    sizeof(Sto_Cls_t *) * p->pCnf->nVars*2 );
+
+    // compute the number of common variables
+    Inta_ManGlobalVars( p );
+
+    // check if resizing of clauses is needed
+    if ( p->nClosAlloc < p->pCnf->nClauses )
+    {
+        // find the new size
+        if ( p->nClosAlloc == 0 )
+            p->nClosAlloc = 1;
+        while ( p->nClosAlloc < p->pCnf->nClauses ) 
+            p->nClosAlloc *= 2;
+        // resize the arrays
+        p->pProofNums = (int *) realloc( p->pProofNums,  sizeof(int) * p->nClosAlloc );
+    }
+    memset( p->pProofNums, 0, sizeof(int) * p->pCnf->nClauses );
+
+    // check if resizing of truth tables is needed
+    if ( p->nIntersAlloc < p->pCnf->nClauses )
+    {
+        p->nIntersAlloc = p->pCnf->nClauses;
+        p->pInters = (Aig_Obj_t **) realloc( p->pInters, sizeof(Aig_Obj_t *) * p->nIntersAlloc );
+    }
+    memset( p->pInters, 0, sizeof(Aig_Obj_t *) * p->pCnf->nClauses );
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Deallocate proof manager.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Inta_ManFree( Inta_Man_t * p )
+{
+/*
+    printf( "Runtime stats:\n" );
+PRT( "BCP     ", p->timeBcp   );
+PRT( "Trace   ", p->timeTrace );
+PRT( "TOTAL   ", p->timeTotal );
+*/
+    free( p->pInters );
+    free( p->pProofNums );
+    free( p->pTrail );
+    free( p->pAssigns );
+    free( p->pSeens );
+    free( p->pVarTypes );
+    free( p->pReasons );
+    free( p->pWatches );
+    free( p->pResLits );
+    free( p );
+}
+
+
+
+
+/**Function*************************************************************
+
+  Synopsis    [Prints the clause.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Inta_ManPrintClause( Inta_Man_t * p, Sto_Cls_t * pClause )
+{
+    int i;
+    printf( "Clause ID = %d. Proof = %d. {", pClause->Id, Inta_ManProofGet(p, pClause) );
+    for ( i = 0; i < (int)pClause->nLits; i++ )
+        printf( " %d", pClause->pLits[i] );
+    printf( " }\n" );
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Prints the resolvent.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Inta_ManPrintResolvent( lit * pResLits, int nResLits )
+{
+    int i;
+    printf( "Resolvent: {" );
+    for ( i = 0; i < nResLits; i++ )
+        printf( " %d", pResLits[i] );
+    printf( " }\n" );
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Prints the interpolant for one clause.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Inta_ManPrintInterOne( Inta_Man_t * p, Sto_Cls_t * pClause )
+{
+    printf( "Clause %2d :  ", pClause->Id );
+//    Extra_PrintBinary___( stdout, Inta_ManAigRead(p, pClause), (1 << p->nVarsAB) );
+    printf( "\n" );
+}
+
+
+
+/**Function*************************************************************
+
+  Synopsis    [Adds one clause to the watcher list.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+static inline void Inta_ManWatchClause( Inta_Man_t * p, Sto_Cls_t * pClause, lit Lit )
+{
+    assert( lit_check(Lit, p->pCnf->nVars) );
+    if ( pClause->pLits[0] == Lit )
+        pClause->pNext0 = p->pWatches[lit_neg(Lit)];  
+    else
+    {
+        assert( pClause->pLits[1] == Lit );
+        pClause->pNext1 = p->pWatches[lit_neg(Lit)];  
+    }
+    p->pWatches[lit_neg(Lit)] = pClause;
+}
+
+
+/**Function*************************************************************
+
+  Synopsis    [Records implication.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+static inline int Inta_ManEnqueue( Inta_Man_t * p, lit Lit, Sto_Cls_t * pReason )
+{
+    int Var = lit_var(Lit);
+    if ( p->pAssigns[Var] != LIT_UNDEF )
+        return p->pAssigns[Var] == Lit;
+    p->pAssigns[Var] = Lit;
+    p->pReasons[Var] = pReason;
+    p->pTrail[p->nTrailSize++] = Lit;
+//printf( "assigning var %d value %d\n", Var, !lit_sign(Lit) );
+    return 1;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Records implication.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+static inline void Inta_ManCancelUntil( Inta_Man_t * p, int Level )
+{
+    lit Lit;
+    int i, Var;
+    for ( i = p->nTrailSize - 1; i >= Level; i-- )
+    {
+        Lit = p->pTrail[i];
+        Var = lit_var( Lit );
+        p->pReasons[Var] = NULL;
+        p->pAssigns[Var] = LIT_UNDEF;
+//printf( "cancelling var %d\n", Var );
+    }
+    p->nTrailSize = Level;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Propagate one assignment.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+static inline Sto_Cls_t * Inta_ManPropagateOne( Inta_Man_t * p, lit Lit )
+{
+    Sto_Cls_t ** ppPrev, * pCur, * pTemp;
+    lit LitF = lit_neg(Lit);
+    int i;
+    // iterate through the literals
+    ppPrev = p->pWatches + Lit;
+    for ( pCur = p->pWatches[Lit]; pCur; pCur = *ppPrev )
+    {
+        // make sure the false literal is in the second literal of the clause
+        if ( pCur->pLits[0] == LitF )
+        {
+            pCur->pLits[0] = pCur->pLits[1];
+            pCur->pLits[1] = LitF;
+            pTemp = pCur->pNext0;
+            pCur->pNext0 = pCur->pNext1;
+            pCur->pNext1 = pTemp;
+        }
+        assert( pCur->pLits[1] == LitF );
+
+        // if the first literal is true, the clause is satisfied
+        if ( pCur->pLits[0] == p->pAssigns[lit_var(pCur->pLits[0])] )
+        {
+            ppPrev = &pCur->pNext1;
+            continue;
+        }
+
+        // look for a new literal to watch
+        for ( i = 2; i < (int)pCur->nLits; i++ )
+        {
+            // skip the case when the literal is false
+            if ( lit_neg(pCur->pLits[i]) == p->pAssigns[lit_var(pCur->pLits[i])] )
+                continue;
+            // the literal is either true or unassigned - watch it
+            pCur->pLits[1] = pCur->pLits[i];
+            pCur->pLits[i] = LitF;
+            // remove this clause from the watch list of Lit
+            *ppPrev = pCur->pNext1;
+            // add this clause to the watch list of pCur->pLits[i] (now it is pCur->pLits[1])
+            Inta_ManWatchClause( p, pCur, pCur->pLits[1] );
+            break;
+        }
+        if ( i < (int)pCur->nLits ) // found new watch
+            continue;
+
+        // clause is unit - enqueue new implication
+        if ( Inta_ManEnqueue(p, pCur->pLits[0], pCur) )
+        {
+            ppPrev = &pCur->pNext1;
+            continue;
+        }
+
+        // conflict detected - return the conflict clause
+        return pCur;
+    }
+    return NULL;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Propagate the current assignments.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Sto_Cls_t * Inta_ManPropagate( Inta_Man_t * p, int Start )
+{
+    Sto_Cls_t * pClause;
+    int i;
+    int clk = clock();
+    for ( i = Start; i < p->nTrailSize; i++ )
+    {
+        pClause = Inta_ManPropagateOne( p, p->pTrail[i] );
+        if ( pClause )
+        {
+p->timeBcp += clock() - clk;
+            return pClause;
+        }
+    }
+p->timeBcp += clock() - clk;
+    return NULL;
+}
+
+
+/**Function*************************************************************
+
+  Synopsis    [Writes one root clause into a file.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Inta_ManProofWriteOne( Inta_Man_t * p, Sto_Cls_t * pClause )
+{
+    Inta_ManProofSet( p, pClause, ++p->Counter );
+
+    if ( p->fProofWrite )
+    {
+        int v;
+        fprintf( p->pFile, "%d", Inta_ManProofGet(p, pClause) );
+        for ( v = 0; v < (int)pClause->nLits; v++ )
+            fprintf( p->pFile, " %d", lit_print(pClause->pLits[v]) );
+        fprintf( p->pFile, " 0 0\n" );
+    }
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Traces the proof for one clause.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Inta_ManProofTraceOne( Inta_Man_t * p, Sto_Cls_t * pConflict, Sto_Cls_t * pFinal )
+{
+    Sto_Cls_t * pReason;
+    int i, v, Var, PrevId;
+    int fPrint = 0;
+    int clk = clock();
+
+    // collect resolvent literals
+    if ( p->fProofVerif )
+    {
+        assert( (int)pConflict->nLits <= p->nResLitsAlloc );
+        memcpy( p->pResLits, pConflict->pLits, sizeof(lit) * pConflict->nLits );
+        p->nResLits = pConflict->nLits;
+    }
+
+    // mark all the variables in the conflict as seen
+    for ( v = 0; v < (int)pConflict->nLits; v++ )
+        p->pSeens[lit_var(pConflict->pLits[v])] = 1;
+
+    // start the anticedents
+//    pFinal->pAntis = Vec_PtrAlloc( 32 );
+//    Vec_PtrPush( pFinal->pAntis, pConflict );
+
+    if ( p->pCnf->nClausesA )
+        Inta_ManAigCopy( p, Inta_ManAigRead(p, pFinal), Inta_ManAigRead(p, pConflict) );
+
+    // follow the trail backwards
+    PrevId = Inta_ManProofGet(p, pConflict);
+    for ( i = p->nTrailSize - 1; i >= 0; i-- )
+    {
+        // skip literals that are not involved
+        Var = lit_var(p->pTrail[i]);
+        if ( !p->pSeens[Var] )
+            continue;
+        p->pSeens[Var] = 0;
+
+        // skip literals of the resulting clause
+        pReason = p->pReasons[Var];
+        if ( pReason == NULL )
+            continue;
+        assert( p->pTrail[i] == pReason->pLits[0] );
+
+        // add the variables to seen
+        for ( v = 1; v < (int)pReason->nLits; v++ )
+            p->pSeens[lit_var(pReason->pLits[v])] = 1;
+
+        // record the reason clause
+        assert( Inta_ManProofGet(p, pReason) > 0 );
+        p->Counter++;
+        if ( p->fProofWrite )
+            fprintf( p->pFile, "%d * %d %d 0\n", p->Counter, PrevId, Inta_ManProofGet(p, pReason) );
+        PrevId = p->Counter;
+
+        if ( p->pCnf->nClausesA )
+        {
+            if ( p->pVarTypes[Var] == 1 ) // var of A
+                Inta_ManAigOr( p, Inta_ManAigRead(p, pFinal), Inta_ManAigRead(p, pReason) );
+            else
+                Inta_ManAigAnd( p, Inta_ManAigRead(p, pFinal), Inta_ManAigRead(p, pReason) );
+        }
+ 
+        // resolve the temporary resolvent with the reason clause
+        if ( p->fProofVerif )
+        {
+            int v1, v2; 
+            if ( fPrint )
+                Inta_ManPrintResolvent( p->pResLits, p->nResLits );
+            // check that the var is present in the resolvent
+            for ( v1 = 0; v1 < p->nResLits; v1++ )
+                if ( lit_var(p->pResLits[v1]) == Var )
+                    break;
+            if ( v1 == p->nResLits )
+                printf( "Recording clause %d: Cannot find variable %d in the temporary resolvent.\n", pFinal->Id, Var );
+            if ( p->pResLits[v1] != lit_neg(pReason->pLits[0]) )
+                printf( "Recording clause %d: The resolved variable %d is in the wrong polarity.\n", pFinal->Id, Var );
+            // remove this variable from the resolvent
+            assert( lit_var(p->pResLits[v1]) == Var );
+            p->nResLits--;
+            for ( ; v1 < p->nResLits; v1++ )
+                p->pResLits[v1] = p->pResLits[v1+1];
+            // add variables of the reason clause
+            for ( v2 = 1; v2 < (int)pReason->nLits; v2++ )
+            {
+                for ( v1 = 0; v1 < p->nResLits; v1++ )
+                    if ( lit_var(p->pResLits[v1]) == lit_var(pReason->pLits[v2]) )
+                        break;
+                // if it is a new variable, add it to the resolvent
+                if ( v1 == p->nResLits ) 
+                {
+                    if ( p->nResLits == p->nResLitsAlloc )
+                        printf( "Recording clause %d: Ran out of space for intermediate resolvent.\n", pFinal->Id );
+                    p->pResLits[ p->nResLits++ ] = pReason->pLits[v2];
+                    continue;
+                }
+                // if the variable is the same, the literal should be the same too
+                if ( p->pResLits[v1] == pReason->pLits[v2] )
+                    continue;
+                // the literal is different
+                printf( "Recording clause %d: Trying to resolve the clause with more than one opposite literal.\n", pFinal->Id );
+            }
+        }
+//        Vec_PtrPush( pFinal->pAntis, pReason );
+    }
+
+    // unmark all seen variables
+//    for ( i = p->nTrailSize - 1; i >= 0; i-- )
+//        p->pSeens[lit_var(p->pTrail[i])] = 0;
+    // check that the literals are unmarked
+//    for ( i = p->nTrailSize - 1; i >= 0; i-- )
+//        assert( p->pSeens[lit_var(p->pTrail[i])] == 0 );
+
+    // use the resulting clause to check the correctness of resolution
+    if ( p->fProofVerif )
+    {
+        int v1, v2; 
+        if ( fPrint )
+            Inta_ManPrintResolvent( p->pResLits, p->nResLits );
+        for ( v1 = 0; v1 < p->nResLits; v1++ )
+        {
+            for ( v2 = 0; v2 < (int)pFinal->nLits; v2++ )
+                if ( pFinal->pLits[v2] == p->pResLits[v1] )
+                    break;
+            if ( v2 < (int)pFinal->nLits )
+                continue;
+            break;
+        }
+        if ( v1 < p->nResLits )
+        {
+            printf( "Recording clause %d: The final resolvent is wrong.\n", pFinal->Id );
+            Inta_ManPrintClause( p, pConflict );
+            Inta_ManPrintResolvent( p->pResLits, p->nResLits );
+            Inta_ManPrintClause( p, pFinal );
+        }
+
+        // if there are literals in the clause that are not in the resolvent
+        // it means that the derived resolvent is stronger than the clause
+        // we can replace the clause with the resolvent by removing these literals
+        if ( p->nResLits != (int)pFinal->nLits )
+        {
+            for ( v1 = 0; v1 < (int)pFinal->nLits; v1++ )
+            {
+                for ( v2 = 0; v2 < p->nResLits; v2++ )
+                    if ( pFinal->pLits[v1] == p->pResLits[v2] )
+                        break;
+                if ( v2 < p->nResLits )
+                    continue;
+                // remove literal v1 from the final clause
+                pFinal->nLits--;
+                for ( v2 = v1; v2 < (int)pFinal->nLits; v2++ )
+                    pFinal->pLits[v2] = pFinal->pLits[v2+1];
+                v1--;
+            }
+            assert( p->nResLits == (int)pFinal->nLits );
+        }
+    }
+p->timeTrace += clock() - clk;
+
+    // return the proof pointer 
+    if ( p->pCnf->nClausesA )
+    {
+//        Inta_ManPrintInterOne( p, pFinal );
+    }
+    Inta_ManProofSet( p, pFinal, p->Counter );
+    return p->Counter;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Records the proof for one clause.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Inta_ManProofRecordOne( Inta_Man_t * p, Sto_Cls_t * pClause )
+{
+    Sto_Cls_t * pConflict;
+    int i;
+
+    // empty clause never ends up there
+    assert( pClause->nLits > 0 );
+    if ( pClause->nLits == 0 )
+        printf( "Error: Empty clause is attempted.\n" );
+
+    assert( !pClause->fRoot );
+    assert( p->nTrailSize == p->nRootSize );
+
+    // if any of the clause literals are already assumed
+    // it means that the clause is redundant and can be skipped
+    for ( i = 0; i < (int)pClause->nLits; i++ )
+        if ( p->pAssigns[lit_var(pClause->pLits[i])] == pClause->pLits[i] )
+            return 1;
+
+    // add assumptions to the trail
+    for ( i = 0; i < (int)pClause->nLits; i++ )
+        if ( !Inta_ManEnqueue( p, lit_neg(pClause->pLits[i]), NULL ) )
+        {
+            assert( 0 ); // impossible
+            return 0;
+        }
+
+    // propagate the assumptions
+    pConflict = Inta_ManPropagate( p, p->nRootSize );
+    if ( pConflict == NULL )
+    {
+        assert( 0 ); // cannot prove
+        return 0;
+    }
+
+    // construct the proof
+    Inta_ManProofTraceOne( p, pConflict, pClause );
+
+    // undo to the root level
+    Inta_ManCancelUntil( p, p->nRootSize );
+
+    // add large clauses to the watched lists
+    if ( pClause->nLits > 1 )
+    {
+        Inta_ManWatchClause( p, pClause, pClause->pLits[0] );
+        Inta_ManWatchClause( p, pClause, pClause->pLits[1] );
+        return 1;
+    }
+    assert( pClause->nLits == 1 );
+
+    // if the clause proved is unit, add it and propagate
+    if ( !Inta_ManEnqueue( p, pClause->pLits[0], pClause ) )
+    {
+        assert( 0 ); // impossible
+        return 0;
+    }
+
+    // propagate the assumption
+    pConflict = Inta_ManPropagate( p, p->nRootSize );
+    if ( pConflict )
+    {
+        // construct the proof
+        Inta_ManProofTraceOne( p, pConflict, p->pCnf->pEmpty );
+//        if ( p->fVerbose )
+//            printf( "Found last conflict after adding unit clause number %d!\n", pClause->Id );
+        return 0;
+    }
+
+    // update the root level
+    p->nRootSize = p->nTrailSize;
+    return 1;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Propagate the root clauses.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Inta_ManProcessRoots( Inta_Man_t * p )
+{
+    Sto_Cls_t * pClause;
+    int Counter;
+
+    // make sure the root clauses are preceeding the learnt clauses
+    Counter = 0;
+    Sto_ManForEachClause( p->pCnf, pClause )
+    {
+        assert( (int)pClause->fA    == (Counter < (int)p->pCnf->nClausesA) );
+        assert( (int)pClause->fRoot == (Counter < (int)p->pCnf->nRoots)    );
+        Counter++;
+    }
+    assert( p->pCnf->nClauses == Counter );
+
+    // make sure the last clause if empty
+    assert( p->pCnf->pTail->nLits == 0 );
+
+    // go through the root unit clauses
+    p->nTrailSize = 0;
+    Sto_ManForEachClauseRoot( p->pCnf, pClause )
+    {
+        // create watcher lists for the root clauses
+        if ( pClause->nLits > 1 )
+        {
+            Inta_ManWatchClause( p, pClause, pClause->pLits[0] );
+            Inta_ManWatchClause( p, pClause, pClause->pLits[1] );
+        }
+        // empty clause and large clauses
+        if ( pClause->nLits != 1 )
+            continue;
+        // unit clause
+        assert( lit_check(pClause->pLits[0], p->pCnf->nVars) );
+        if ( !Inta_ManEnqueue( p, pClause->pLits[0], pClause ) )
+        {
+            // detected root level conflict
+//            printf( "Error in Inta_ManProcessRoots(): Detected a root-level conflict too early!\n" );
+//            assert( 0 );
+            // detected root level conflict
+            Inta_ManProofTraceOne( p, pClause, p->pCnf->pEmpty );
+            if ( p->fVerbose )
+                printf( "Found root level conflict!\n" );
+            return 0;
+        }
+    }
+
+    // propagate the root unit clauses
+    pClause = Inta_ManPropagate( p, 0 );
+    if ( pClause )
+    {
+        // detected root level conflict
+        Inta_ManProofTraceOne( p, pClause, p->pCnf->pEmpty );
+        if ( p->fVerbose )
+            printf( "Found root level conflict!\n" );
+        return 0;
+    }
+
+    // set the root level
+    p->nRootSize = p->nTrailSize;
+    return 1;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Records the proof.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Inta_ManPrepareInter( Inta_Man_t * p )
+{
+    Sto_Cls_t * pClause;
+    int Var, VarAB, v;
+
+    // set interpolants for root clauses
+    Sto_ManForEachClauseRoot( p->pCnf, pClause )
+    {
+        if ( !pClause->fA ) // clause of B
+        {
+            Inta_ManAigFill( p, Inta_ManAigRead(p, pClause) );
+//            Inta_ManPrintInterOne( p, pClause );
+            continue;
+        }
+        // clause of A
+        Inta_ManAigClear( p, Inta_ManAigRead(p, pClause) );
+        for ( v = 0; v < (int)pClause->nLits; v++ )
+        {
+            Var = lit_var(pClause->pLits[v]);
+            if ( p->pVarTypes[Var] < 0 ) // global var
+            {
+                VarAB = -p->pVarTypes[Var]-1;
+                assert( VarAB >= 0 && VarAB < Vec_IntSize(p->vVarsAB) );
+                if ( lit_sign(pClause->pLits[v]) ) // negative var
+                    Inta_ManAigOrNotVar( p, Inta_ManAigRead(p, pClause), VarAB );
+                else
+                    Inta_ManAigOrVar( p, Inta_ManAigRead(p, pClause), VarAB );
+            }
+        }
+//        Inta_ManPrintInterOne( p, pClause );
+    }
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Computes interpolant for the given CNF.]
+
+  Description [Takes the interpolation manager, the CNF deriving by the SAT
+  solver, which includes ClausesA, ClausesB, and learned clauses. Additional
+  arguments are the vector of variables common to AB and the verbosiness flag.
+  Returns the AIG manager with a single output, containing the interpolant.]
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void * Inta_ManInterpolate( Inta_Man_t * p, Sto_Man_t * pCnf, void * vVarsAB, int fVerbose )
+{
+    Aig_Man_t * pRes;
+    Aig_Obj_t * pObj;
+    Sto_Cls_t * pClause;
+    int RetValue = 1;
+    int clkTotal = clock();
+
+    // check that the CNF makes sense
+    assert( pCnf->nVars > 0 && pCnf->nClauses > 0 );
+    p->pCnf = pCnf;
+    p->fVerbose = fVerbose;
+    p->vVarsAB = vVarsAB;
+    p->pAig = pRes = Aig_ManStart( 10000 );
+    Aig_IthVar( p->pAig, Vec_IntSize(p->vVarsAB) - 1 );
+
+    // adjust the manager
+    Inta_ManResize( p );
+
+    // prepare the interpolant computation
+    Inta_ManPrepareInter( p );
+
+    // construct proof for each clause
+    // start the proof
+    if ( p->fProofWrite )
+    {
+        p->pFile = fopen( "proof.cnf_", "w" );
+        p->Counter = 0;
+    }
+
+    // write the root clauses
+    Sto_ManForEachClauseRoot( p->pCnf, pClause )
+        Inta_ManProofWriteOne( p, pClause );
+
+    // propagate root level assignments
+    if ( Inta_ManProcessRoots( p ) )
+    {
+        // if there is no conflict, consider learned clauses
+        Sto_ManForEachClause( p->pCnf, pClause )
+        {
+            if ( pClause->fRoot )
+                continue;
+            if ( !Inta_ManProofRecordOne( p, pClause ) )
+            {
+                RetValue = 0;
+                break;
+            }
+        }
+    }
+
+    // stop the proof
+    if ( p->fProofWrite )
+    { 
+        fclose( p->pFile );
+        p->pFile = NULL;    
+    }
+
+    if ( fVerbose )
+    {
+//        PRT( "Interpo", clock() - clkTotal );
+    printf( "Vars = %d. Roots = %d. Learned = %d. Resol steps = %d.  Ave = %.2f.  Mem = %.2f Mb\n", 
+        p->pCnf->nVars, p->pCnf->nRoots, p->pCnf->nClauses-p->pCnf->nRoots, p->Counter,  
+        1.0*(p->Counter-p->pCnf->nRoots)/(p->pCnf->nClauses-p->pCnf->nRoots), 
+        1.0*Sto_ManMemoryReport(p->pCnf)/(1<<20) );
+p->timeTotal += clock() - clkTotal;
+    }
+
+    pObj = *Inta_ManAigRead( p, p->pCnf->pTail );
+    Aig_ObjCreatePo( pRes, pObj );
+    Aig_ManCleanup( pRes );
+
+    p->pAig = NULL;
+    return pRes;
+    
+}
+
+
+/**Function*************************************************************
+
+  Synopsis    []
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Aig_Man_t * Inta_ManDeriveClauses( Inta_Man_t * pMan, Sto_Man_t * pCnf, int fClausesA )
+{
+    Aig_Man_t * p;
+    Aig_Obj_t * pMiter, * pSum, * pLit;
+    Sto_Cls_t * pClause;
+    int Var, VarAB, v;
+    p = Aig_ManStart( 10000 );
+    pMiter = Aig_ManConst1(p);
+    Sto_ManForEachClauseRoot( pCnf, pClause )
+    {
+        if ( fClausesA ^ pClause->fA ) // clause of B
+            continue;
+        // clause of A
+        pSum = Aig_ManConst0(p);
+        for ( v = 0; v < (int)pClause->nLits; v++ )
+        {
+            Var = lit_var(pClause->pLits[v]);
+            if ( pMan->pVarTypes[Var] < 0 ) // global var
+            {
+                VarAB = -pMan->pVarTypes[Var]-1;
+                assert( VarAB >= 0 && VarAB < Vec_IntSize(pMan->vVarsAB) );
+                pLit = Aig_NotCond( Aig_IthVar(p, VarAB), lit_sign(pClause->pLits[v]) );
+            }
+            else
+                pLit = Aig_NotCond( Aig_IthVar(p, Vec_IntSize(pMan->vVarsAB)+1+Var), lit_sign(pClause->pLits[v]) );
+            pSum = Aig_Or( p, pSum, pLit );
+        }
+        pMiter = Aig_And( p, pMiter, pSum );
+    }
+    Aig_ObjCreatePo( p, pMiter );
+    return p;
+}
+
+////////////////////////////////////////////////////////////////////////
+///                       END OF FILE                                ///
+////////////////////////////////////////////////////////////////////////
+
+
diff --git a/src/sat/bsat/satInterA_yu_hu.c b/src/sat/bsat/satInterA_yu_hu.c
index 2005e558..aa2289f2 100644
--- a/src/sat/bsat/satInterA_yu_hu.c
+++ b/src/sat/bsat/satInterA_yu_hu.c
@@ -114,6 +114,7 @@ Inta_Man_t * Inta_ManAlloc()
     // parameters
     p->fProofWrite = 1;
     p->fProofVerif = 1;
+
     return p;    
 }
 
@@ -289,16 +290,6 @@ void Inta_ManPrintClause( Inta_Man_t * p, Sto_Cls_t * pClause )
     printf( " }\n" );
 }
 
-// Yu Hu
-void Inta_ManPrintClauseEx( lit * pResLits, int nResLits )
-{
-    int i;
-    printf( " {" );
-    for ( i = 0; i < nResLits; i++ )
-        printf( " %d", lit_print(pResLits[i]) );
-    printf( " }\n" );
-}
-
 /**Function*************************************************************
 
   Synopsis    [Prints the resolvent.]
@@ -315,6 +306,8 @@ void Inta_ManPrintResolvent( lit * pResLits, int nResLits )
     int i;
     printf( "Resolvent: {" );
     for ( i = 0; i < nResLits; i++ )
+        // Yu Hu
+        // printf( " %d", pResLits[i] );
         printf( " %d", lit_print(pResLits[i]) );
     printf( " }\n" );
 }
@@ -537,6 +530,17 @@ void Inta_ManProofWriteOne( Inta_Man_t * p, Sto_Cls_t * pClause )
     }
 }
 
+// Yu Hu
+void Inta_ManPrintClauseEx( lit * pResLits, int nResLits )
+{
+    int i;
+    printf( " {" );
+    for ( i = 0; i < nResLits; i++ )
+        printf( " %d", lit_print(pResLits[i]) );
+    printf( " }\n" );
+}
+
+
 /**Function*************************************************************
 
   Synopsis    [Traces the proof for one clause.]
@@ -594,7 +598,6 @@ int Inta_ManProofTraceOne( Inta_Man_t * p, Sto_Cls_t * pConflict, Sto_Cls_t * pF
         for ( v = 1; v < (int)pReason->nLits; v++ )
             p->pSeens[lit_var(pReason->pLits[v])] = 1;
 
-
         // record the reason clause
         assert( Inta_ManProofGet(p, pReason) > 0 );
         p->Counter++;
@@ -617,14 +620,15 @@ int Inta_ManProofTraceOne( Inta_Man_t * p, Sto_Cls_t * pConflict, Sto_Cls_t * pF
         if ( p->fProofVerif )
         {
             int v1, v2; 
+
             // Yu Hu
-//            if ( fPrint )
-//                Inta_ManPrintResolvent( p->pResLits, p->nResLits );
-            if ( fPrint ) {
-                printf("pivot = %d,\n", lit_print(p->pTrail[i]));
-                Inta_ManPrintClauseEx( p->pResLits, p->nResLits);
-            }
- 
+            // if ( fPrint )
+            //     Inta_ManPrintResolvent( p->pResLits, p->nResLits );
+            if ( fPrint ) {                                                                                                
+                printf("pivot = %d,\n", lit_print(p->pTrail[i]));                                                          
+                Inta_ManPrintClauseEx( p->pResLits, p->nResLits);                                                          
+            }                                                          
+
             // check that the var is present in the resolvent
             for ( v1 = 0; v1 < p->nResLits; v1++ )
                 if ( lit_var(p->pResLits[v1]) == Var )
@@ -660,12 +664,12 @@ int Inta_ManProofTraceOne( Inta_Man_t * p, Sto_Cls_t * pConflict, Sto_Cls_t * pF
             }
 
             // Yu Hu
-            if ( fPrint ) {
-                Inta_ManPrintClauseEx( pReason->pLits, pReason->nLits);
-                Inta_ManPrintResolvent( p->pResLits, p->nResLits );
-            }
-        }
+            if ( fPrint ) {                                                                                                
+                Inta_ManPrintClauseEx( pReason->pLits, pReason->nLits);                                                    
+                Inta_ManPrintResolvent( p->pResLits, p->nResLits);                                                        
+            }            
 
+        }
 //        Vec_PtrPush( pFinal->pAntis, pReason );
     }
 
@@ -680,10 +684,11 @@ int Inta_ManProofTraceOne( Inta_Man_t * p, Sto_Cls_t * pConflict, Sto_Cls_t * pF
     if ( p->fProofVerif )
     {
         int v1, v2; 
-        if ( fPrint ){
-            // Yu Hu
+
+        // Yu Hu
+//        if ( fPrint )
 //            Inta_ManPrintResolvent( p->pResLits, p->nResLits );
-        }
+
         for ( v1 = 0; v1 < p->nResLits; v1++ )
         {
             for ( v2 = 0; v2 < (int)pFinal->nLits; v2++ )
@@ -700,6 +705,27 @@ int Inta_ManProofTraceOne( Inta_Man_t * p, Sto_Cls_t * pConflict, Sto_Cls_t * pF
             Inta_ManPrintResolvent( p->pResLits, p->nResLits );
             Inta_ManPrintClause( p, pFinal );
         }
+
+        // if there are literals in the clause that are not in the resolvent
+        // it means that the derived resolvent is stronger than the clause
+        // we can replace the clause with the resolvent by removing these literals
+        if ( p->nResLits != (int)pFinal->nLits )
+        {
+            for ( v1 = 0; v1 < (int)pFinal->nLits; v1++ )
+            {
+                for ( v2 = 0; v2 < p->nResLits; v2++ )
+                    if ( pFinal->pLits[v1] == p->pResLits[v2] )
+                        break;
+                if ( v2 < p->nResLits )
+                    continue;
+                // remove literal v1 from the final clause
+                pFinal->nLits--;
+                for ( v2 = v1; v2 < (int)pFinal->nLits; v2++ )
+                    pFinal->pLits[v2] = pFinal->pLits[v2+1];
+                v1--;
+            }
+            assert( p->nResLits == (int)pFinal->nLits );
+        }
     }
 p->timeTrace += clock() - clk;
 
@@ -733,9 +759,16 @@ int Inta_ManProofRecordOne( Inta_Man_t * p, Sto_Cls_t * pClause )
     if ( pClause->nLits == 0 )
         printf( "Error: Empty clause is attempted.\n" );
 
-    // add assumptions to the trail
     assert( !pClause->fRoot );
     assert( p->nTrailSize == p->nRootSize );
+
+    // if any of the clause literals are already assumed
+    // it means that the clause is redundant and can be skipped
+    for ( i = 0; i < (int)pClause->nLits; i++ )
+        if ( p->pAssigns[lit_var(pClause->pLits[i])] == pClause->pLits[i] )
+            return 1;
+
+    // add assumptions to the trail
     for ( i = 0; i < (int)pClause->nLits; i++ )
         if ( !Inta_ManEnqueue( p, lit_neg(pClause->pLits[i]), NULL ) )
         {
diff --git a/src/sat/lsat/solver.h b/src/sat/lsat/solver.h
new file mode 100644
index 00000000..a15e42d6
--- /dev/null
+++ b/src/sat/lsat/solver.h
@@ -0,0 +1,124 @@
+/****************************************************************************************[solver.h]
+Copyright (c) 2008, Niklas Sorensson
+              2008, Koen Claessen
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of this software and
+associated documentation files (the "Software"), to deal in the Software without restriction,
+including without limitation the rights to use, copy, modify, merge, publish, distribute,
+sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all copies or
+substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT
+NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT
+OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+**************************************************************************************************/
+
+#ifndef Minisat_solver_h
+#define Minisat_solver_h
+
+// SolverTypes:
+//
+typedef struct solver_t solver;
+typedef int solver_Var;
+typedef int solver_Lit;
+typedef int solver_lbool;
+
+// Constants: (can these be made inline-able?)
+//
+
+extern const solver_lbool solver_l_True;
+extern const solver_lbool solver_l_False;
+extern const solver_lbool solver_l_Undef;
+
+
+solver*      solver_new             (void);
+void         solver_delete          (solver* s);
+             
+solver_Var   solver_newVar          (solver *s);
+solver_Lit   solver_newLit          (solver *s);
+             
+solver_Lit   solver_mkLit           (solver_Var x);
+solver_Lit   solver_mkLit_args      (solver_Var x, int sign);
+solver_Lit   solver_negate          (solver_Lit p);
+                                    
+solver_Var   solver_var             (solver_Lit p);
+int          solver_sign            (solver_Lit p);
+             
+int          solver_addClause       (solver *s, int len, solver_Lit *ps);
+void         solver_addClause_begin (solver *s);
+void         solver_addClause_addLit(solver *s, solver_Lit p);
+int          solver_addClause_commit(solver *s);
+             
+int          solver_simplify        (solver *s);
+             
+int          solver_solve           (solver *s, int len, solver_Lit *ps);
+void         solver_solve_begin     (solver *s);
+void         solver_solve_addLit    (solver *s, solver_Lit p);
+int          solver_solve_commit    (solver *s);
+             
+int          solver_okay            (solver *s);
+             
+void         solver_setPolarity     (solver *s, solver_Var v, int b);
+void         solver_setDecisionVar  (solver *s, solver_Var v, int b);
+
+solver_lbool solver_get_l_True      (void);
+solver_lbool solver_get_l_False     (void);
+solver_lbool solver_get_l_Undef     (void);
+
+solver_lbool solver_value_Var       (solver *s, solver_Var x);
+solver_lbool solver_value_Lit       (solver *s, solver_Lit p);
+
+solver_lbool solver_modelValue_Var  (solver *s, solver_Var x);
+solver_lbool solver_modelValue_Lit  (solver *s, solver_Lit p);
+
+int          solver_num_assigns     (solver *s);
+int          solver_num_clauses     (solver *s);     
+int          solver_num_learnts     (solver *s);     
+int          solver_num_vars        (solver *s);  
+int          solver_num_freeVars    (solver *s);
+
+int          solver_conflict_len    (solver *s);
+solver_Lit   solver_conflict_nthLit (solver *s, int i);
+
+// Setters:
+
+void         solver_set_verbosity   (solver *s, int v);
+
+// Getters:
+
+int          solver_num_conflicts   (solver *s);
+
+/* TODO
+
+    // Mode of operation:
+    //
+    int       verbosity;
+    double    var_decay;
+    double    clause_decay;
+    double    random_var_freq;
+    double    random_seed;
+    double    restart_luby_start; // The factor with which the values of the luby sequence is multiplied to get the restart    (default 100)
+    double    restart_luby_inc;   // The constant that the luby sequence uses powers of                                        (default 2)
+    bool      expensive_ccmin;    // FIXME: describe.
+    bool      rnd_pol;            // FIXME: describe.
+
+    int       restart_first;      // The initial restart limit.                                                                (default 100)
+    double    restart_inc;        // The factor with which the restart limit is multiplied in each restart.                    (default 1.5)
+    double    learntsize_factor;  // The intitial limit for learnt clauses is a factor of the original clauses.                (default 1 / 3)
+    double    learntsize_inc;     // The limit for learnt clauses is multiplied with this factor each restart.                 (default 1.1)
+
+    int       learntsize_adjust_start_confl;
+    double    learntsize_adjust_inc;
+
+    // Statistics: (read-only member variable)
+    //
+    uint64_t starts, decisions, rnd_decisions, propagations, conflicts;
+    uint64_t dec_vars, clauses_literals, learnts_literals, max_literals, tot_literals;
+*/
+
+#endif