Variable timeframe abstraction.

7 files changed, 535 insertions, 169 deletions

diff --git a/src/aig/gia/gia.h b/src/aig/gia/gia.h
index 4ca6930b..98766396 100644
--- a/src/aig/gia/gia.h
+++ b/src/aig/gia/gia.h
@@ -134,6 +134,7 @@ struct Gia_Man_t_
     Vec_Int_t *    vTruths;       // used for truth table computation
     Vec_Int_t *    vFlopClasses;  // classes of flops for retiming/merging/etc
     Vec_Int_t *    vGateClasses;  // classes of gates for abstraction
+    Vec_Int_t *    vObjClasses;   // classes of objects for abstraction
     unsigned char* pSwitching;    // switching activity for each object
     Gia_Plc_t *    pPlacement;    // placement of the objects
     int *          pTravIds;      // separate traversal ID representation
@@ -703,6 +704,8 @@ extern void                Gia_ManFanoutStop( Gia_Man_t * p );
 /*=== giaForce.c =========================================================*/
 extern void                For_ManExperiment( Gia_Man_t * pGia, int nIters, int fClustered, int fVerbose );
 /*=== giaFrames.c =========================================================*/
+extern Gia_Man_t *         Gia_ManUnrollDup( Gia_Man_t * p, Vec_Int_t * vLimit );
+extern Vec_Ptr_t *         Gia_ManUnrollAbs( Gia_Man_t * p, int nFrames );
 extern void *              Gia_ManUnrollStart( Gia_Man_t * pAig, Gia_ParFra_t * pPars );
 extern void *              Gia_ManUnrollAdd( void * pMan, int fMax );
 extern void                Gia_ManUnrollStop( void * pMan );
diff --git a/src/aig/gia/giaAbsVta.c b/src/aig/gia/giaAbsVta.c
index 0afec5e0..06988cf9 100644
--- a/src/aig/gia/giaAbsVta.c
+++ b/src/aig/gia/giaAbsVta.c
@@ -46,6 +46,7 @@ struct Vta_Man_t_
 {
     // user data
     Gia_Man_t *   pGia;         // AIG manager
+    int           nFramesStart; // the number of starting frames
     int           nFramesMax;   // maximum number of frames
     int           nConfMax;     // conflict limit
     int           nTimeMax;     // runtime limit
@@ -59,11 +60,11 @@ struct Vta_Man_t_
     Vta_Obj_t *   pObjs;        // hash table bins
     Vec_Int_t *   vOrder;       // objects in DPS order
     // abstraction
-    int           nWords;       // the number of sim words for abs
-    int           nFramesS;     // the number of copmleted frames
-    Vec_Int_t *   vAbs;         // starting abstraction
-    Vec_Int_t *   vAbsNew;      // computed abstraction
-    Vec_Int_t *   vAbsAll;      // abstraction of all timeframes
+    int           nObjBits;     // the number of bits to represent objects
+    unsigned      nObjMask;     // object mask
+    Vec_Ptr_t *   vFrames;      // start abstraction for each frame
+    int           nWords;       // the number of words in the record
+    Vec_Int_t *   vSeens;       // seen objects
     // other data
     Vec_Int_t *   vCla2Var;     // map clauses into variables
     Vec_Ptr_t *   vCores;       // unsat core for each frame
@@ -86,8 +87,8 @@ static inline int Vta_ValIs1( Vta_Obj_t * pThis, int fCompl )
 static inline Vta_Obj_t *  Vta_ManObj( Vta_Man_t * p, int i )           { assert( i >= 0 && i < p->nObjs ); return i ? p->pObjs + i : NULL;                     }
 static inline int          Vta_ObjId( Vta_Man_t * p, Vta_Obj_t * pObj ) { assert( pObj > p->pObjs && pObj < p->pObjs + p->nObjs ); return pObj - p->pObjs;      }
 
-static inline unsigned *   Vta_ObjAbsOld( Vta_Man_t * p, int i )   { assert( i >= 0 && i < p->nObjs ); return (unsigned *)Vec_IntEntryP( p->vAbs,    i*p->nWords ); }
-static inline unsigned *   Vta_ObjAbsNew( Vta_Man_t * p, int i )   { assert( i >= 0 && i < p->nObjs ); return (unsigned *)Vec_IntEntryP( p->vAbsNew, i*p->nWords ); }
+//static inline unsigned *   Vta_ObjAbsOld( Vta_Man_t * p, int i )   { assert( i >= 0 && i < p->nObjs ); return (unsigned *)Vec_IntEntryP( p->vAbs,    i*p->nWords ); }
+//static inline unsigned *   Vta_ObjAbsNew( Vta_Man_t * p, int i )   { assert( i >= 0 && i < p->nObjs ); return (unsigned *)Vec_IntEntryP( p->vAbsNew, i*p->nWords ); }
 
 #define Vta_ManForEachObj( p, pObj, i )                                 \
     for ( i = 1; (i < p->nObjs) && ((pObj) = Vta_ManObj(p, i)); i++ )
@@ -96,12 +97,82 @@ static inline unsigned *   Vta_ObjAbsNew( Vta_Man_t * p, int i )   { assert( i >
 #define Vta_ManForEachObjVecReverse( vVec, p, pObj, i )                        \
     for ( i = Vec_IntSize(vVec) - 1; (i >= 1) && ((pObj) = Vta_ManObj(p, Vec_IntEntry(vVec,i))); i-- )
 
+// abstraction is given as an array of integers:
+// - the first entry is the number of timeframes (F)
+// - the next (F+1) entries give the beginning position of each timeframe
+// - the following entries give the object IDs
+// invariant:  assert( vec[vec[0]+2] == size(vec) );
+
 ////////////////////////////////////////////////////////////////////////
 ///                     FUNCTION DEFINITIONS                         ///
 ////////////////////////////////////////////////////////////////////////
 
 /**Function*************************************************************
 
+  Synopsis    [Converting from one array to per-frame arrays.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Vec_Ptr_t * Vta_ManAbsToFrames( Vec_Int_t * vAbs )
+{
+    Vec_Ptr_t * vFrames;
+    Vec_Int_t * vFrame;
+    int i, k, Entry, iStart, iStop;
+    int nFrames = Vec_IntEntry( vAbs, 0 );
+    assert( Vec_IntEntry(vAbs, nFrames+1) == Vec_IntSize(vAbs) );
+    vFrames = Vec_PtrAlloc( nFrames );
+    for ( i = 0; i < nFrames; i++ )
+    {
+        iStart = Vec_IntEntry( vAbs, i+1 );
+        iStop  = Vec_IntEntry( vAbs, i+2 );
+        vFrame = Vec_IntAlloc( iStop - iStart );
+        Vec_IntForEachEntryStartStop( vAbs, Entry, k, iStart, iStop )
+            Vec_IntPush( vFrame, Entry );
+        Vec_PtrPush( vFrames, vFrame );
+    }
+    assert( iStop == Vec_IntSize(vAbs) );
+    return vFrames;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Converting from per-frame arrays to one integer array.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Vec_Int_t * Vta_ManFramesToAbs( Vec_Vec_t * vFrames )
+{
+    Vec_Int_t * vOne, * vAbs;
+    int i, k, Entry, nSize;
+    vAbs = Vec_IntAlloc( 2 + Vec_VecSize(vFrames) + Vec_VecSizeSize(vFrames) );
+    Vec_IntPush( vAbs, Vec_VecSize(vFrames) );
+    nSize = Vec_VecSize(vFrames) + 2;
+    Vec_VecForEachLevelInt( vFrames, vOne, i )
+    {
+        Vec_IntPush( vAbs, nSize );
+        nSize += Vec_IntSize( vOne );
+    }
+    Vec_IntPush( vAbs, nSize );
+    assert( Vec_IntSize(vAbs) == Vec_VecSize(vFrames) + 2 );
+    Vec_VecForEachLevelInt( vFrames, vOne, i )
+        Vec_IntForEachEntry( vOne, Entry, k )
+            Vec_IntPush( vAbs, Entry );
+    assert( Vec_IntEntry(vAbs, Vec_IntEntry(vAbs,0)+1) == Vec_IntSize(vAbs) );
+    return vAbs;
+}
+
+/**Function*************************************************************
+
   Synopsis    [Detects how many frames are completed.]
 
   Description []
@@ -164,6 +235,88 @@ static inline Vec_Int_t * Vta_ManDeriveAbsAll( Vec_Int_t * p, int nWords )
 
 /**Function*************************************************************
 
+  Synopsis    [Collect nodes/flops involved in different timeframes.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Vec_IntDoubleWidth( Vec_Int_t * p, int nWords )
+{
+    int * pArray = ABC_CALLOC( int, Vec_IntSize(p) * 2 );
+    int i, w, nObjs = Vec_IntSize(p) / nWords;
+    assert( Vec_IntSize(p) % nWords == 0 );
+    for ( i = 0; i < nObjs; i++ )
+        for ( w = 0; w < nWords; w++ )
+            pArray[2 * nWords * i + w] = p->pArray[nWords * i + w];
+    ABC_FREE( p->pArray );
+    p->pArray = pArray;
+    p->nSize *= 2;
+    p->nCap = p->nSize;
+    return 2 * nWords;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Prints the results.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+/*
+void Vta_ManAbsPrint( Vta_Man_t * p, int fThis )
+{
+    Vec_Ptr_t * vInfos;
+    Vec_Int_t * vPres;
+    unsigned * pInfo;
+    int CountAll, CountUni;
+    int Entry, i, w, f;
+    // collected used nodes
+    vInfos = Vec_PtrAlloc( 1000 );
+    Vec_IntForEachEntry( p->vAbsAll, Entry, i )
+    {
+        if ( Entry )
+            Vec_PtrPush( vInfos, Vta_ObjAbsNew(p, i) );
+
+        pInfo = Vta_ObjAbsNew(p, i);
+        for ( w = 0; w < p->nWords; w++ )
+            if ( pInfo[w] )
+                break;
+        assert( Entry == (int)(w < p->nWords) );
+    }
+    printf( "%d", Vec_PtrSize(vInfos) );
+    // print results for used nodes
+    vPres = Vec_IntStart( Vec_PtrSize(vInfos) );
+    for ( f = 0; f <= fThis; f++ )
+    {
+        CountAll = CountUni = 0;
+        Vec_PtrForEachEntry( unsigned *, vInfos, pInfo, i )
+        {
+            if ( !Gia_InfoHasBit(pInfo, f) )
+                continue;
+            CountAll++;
+            if ( Vec_IntEntry(vPres, i) )
+                continue;
+            CountUni++;
+            Vec_IntWriteEntry( vPres, i, 1 );
+        }
+        printf( "  %d(%d)", CountAll, CountUni );
+    }
+    printf( "\n" );
+    Vec_PtrFree( vInfos );
+    Vec_IntFree( vPres );
+}
+*/
+
+/**Function*************************************************************
+
   Synopsis    []
 
   Description []
@@ -173,34 +326,42 @@ static inline Vec_Int_t * Vta_ManDeriveAbsAll( Vec_Int_t * p, int nWords )
   SeeAlso     []
 
 ***********************************************************************/
-Vta_Man_t * Vga_ManStart( Gia_Man_t * pGia, Vec_Int_t * vAbs, int nFramesMax, int nConfMax, int nTimeMax, int fVerbose )
+Vta_Man_t * Vga_ManStart( Gia_Man_t * pGia, int nFramesStart, int nFramesMax, int nConfMax, int nTimeMax, int fVerbose )
 {
     Vta_Man_t * p;
-    assert( nFramesMax > 0 && nFramesMax < 32 );
+    assert( nFramesMax == 0 || nFramesStart <= nFramesMax );
     p = ABC_CALLOC( Vta_Man_t, 1 );
-    p->pGia       = pGia;
-    p->nFramesMax = nFramesMax;    
-    p->nConfMax   = nConfMax;
-    p->nTimeMax   = nTimeMax;
-    p->fVerbose   = fVerbose;
+    p->pGia         = pGia;
+    p->nFramesStart = nFramesStart;    
+    p->nFramesMax   = nFramesMax;    
+    p->nConfMax     = nConfMax;
+    p->nTimeMax     = nTimeMax;
+    p->fVerbose     = fVerbose;
     // internal data
-    p->nObjsAlloc = (1 << 20);
-    p->pObjs      = ABC_CALLOC( Vta_Obj_t, p->nObjsAlloc );
-    p->nObjs      = 1;
-    p->nBins      = Gia_PrimeCudd( p->nObjsAlloc/2 );
-    p->pBins      = ABC_CALLOC( int, p->nBins );
-    p->vOrder     = Vec_IntAlloc( 1013 );
+    p->nObjsAlloc   = (1 << 20);
+    p->pObjs        = ABC_CALLOC( Vta_Obj_t, p->nObjsAlloc );
+    p->nObjs        = 1;
+    p->nBins        = Gia_PrimeCudd( p->nObjsAlloc/2 );
+    p->pBins        = ABC_CALLOC( int, p->nBins );
+    p->vOrder       = Vec_IntAlloc( 1013 );
     // abstraction
-    p->nWords     = vAbs ? Vec_IntSize(vAbs) / Gia_ManObjNum(p->pGia) : 1;
-    p->nFramesS   = vAbs ? Vta_ManReadFrameStart( vAbs, p->nWords ) : Abc_MinInt( p->nFramesMax, 10 );
-    p->vAbs       = vAbs ? Vec_IntDup(vAbs) : Vec_IntStartFull( Gia_ManObjNum(p->pGia) * p->nWords );
-    p->vAbsNew    = Vec_IntStart( Gia_ManObjNum(p->pGia) * p->nWords );
-    p->vAbsAll    = Vta_ManDeriveAbsAll( vAbs, p->nWords );
+    p->nObjBits     = Gia_Base2Log( Gia_ManObjNum(pGia) );
+    p->nObjMask     = (1 << p->nObjBits) - 1;
+    assert( Gia_ManObjNum(pGia) <= (int)p->nObjMask );
+    p->nWords       = 1;
+    p->vSeens       = Vec_IntStart( Gia_ManObjNum(pGia) * p->nWords );
+    // start the abstraction
+    if ( pGia->vObjClasses )
+        p->vFrames  = Vta_ManAbsToFrames( pGia->vObjClasses );
+    else
+        p->vFrames  = Gia_ManUnrollAbs( pGia, nFramesStart );
     // other data
-    p->vCla2Var   = Vec_IntAlloc( 1000 );
-    p->vCores     = Vec_PtrAlloc( 100 );
-    p->pSat       = sat_solver2_new();
-    assert( nFramesMax == 0 || p->nFramesS <= nFramesMax );
+    p->vCla2Var     = Vec_IntAlloc( 1000 );
+    p->vCores       = Vec_PtrAlloc( 100 );
+    p->pSat         = sat_solver2_new();
+
+
+
     return p;
 }
 
@@ -217,10 +378,8 @@ Vta_Man_t * Vga_ManStart( Gia_Man_t * pGia, Vec_Int_t * vAbs, int nFramesMax, in
 ***********************************************************************/
 void Vga_ManStop( Vta_Man_t * p )
 {
-    assert( p->vAbs == NULL );
     Vec_VecFreeP( (Vec_Vec_t **)&p->vCores );
-    Vec_IntFreeP( &p->vAbs );
-    Vec_IntFreeP( &p->vAbsAll );
+    Vec_IntFreeP( &p->vSeens );
     Vec_IntFreeP( &p->vOrder );
     Vec_IntFreeP( &p->vCla2Var );
     sat_solver2_delete( p->pSat );
@@ -422,6 +581,7 @@ Vec_Int_t * Vta_ManUnsatCore( Vec_Int_t * vCla2Var, sat_solver2 * pSat, int nCon
     }
 
     // remap core into variables
+    clk = clock();
     vPres = Vec_IntStart( sat_solver2_nvars(pSat) );
     k = 0; 
     Vec_IntForEachEntry( vCore, Entry, i )
@@ -442,6 +602,28 @@ Vec_Int_t * Vta_ManUnsatCore( Vec_Int_t * vCla2Var, sat_solver2 * pSat, int nCon
     return vCore;
 }
 
+/**Function*************************************************************
+
+  Synopsis    [Remaps core into frame/node pairs.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Vta_ManUnsatCoreRemap( Vta_Man_t * p, Vec_Int_t * vCore )
+{
+    Vta_Obj_t * pThis;
+    int i, Entry;
+    Vec_IntForEachEntry( vCore, Entry, i )
+    {
+        pThis = Vta_ManObj( p, Entry );
+        Entry = (pThis->iFrame << p->nObjBits) | pThis->iObj;
+        Vec_IntWriteEntry( vCore, i, Entry );
+    }
+}
 
 /**Function*************************************************************
 
@@ -519,8 +701,14 @@ Abc_Cex_t * Vta_ManRefineAbstraction( Vta_Man_t * p )
         assert( Gia_ObjIsAnd(pObj) || Gia_ObjIsRo(p->pGia, pObj) );
         if ( !pThis->fAdded )
         {
+            unsigned * pInfo = (unsigned *)Vec_IntEntryP( p->vSeens, p->nWords * pThis->iObj );
+            int i;
+            for ( i = 0; i < p->nWords; i++ )
+                if ( pInfo[i] )
+                    break;
             assert( pThis->Prio > 0 || pThis->Prio < VTA_LARGE );
-            if ( Vec_IntEntry(p->vAbsAll, pThis->iObj) )
+//            if ( Vec_IntEntry(p->vAbsAll, pThis->iObj) )
+            if ( i < p->nWords )
                 Vec_PtrPush( vTermsUsed, pThis );
             else
                 Vec_PtrPush( vTermsUnused, pThis );
@@ -775,85 +963,6 @@ Abc_Cex_t * Vta_ManRefineAbstraction( Vta_Man_t * p )
 
 /**Function*************************************************************
 
-  Synopsis    [Collect nodes/flops involved in different timeframes.]
-
-  Description []
-               
-  SideEffects []
-
-  SeeAlso     []
-
-***********************************************************************/
-void Vec_IntDoubleWidth( Vec_Int_t * p, int nWords )
-{
-    int * pArray = ABC_CALLOC( int, Vec_IntSize(p) * 2 );
-    int i, w, nObjs = Vec_IntSize(p) / nWords;
-    assert( Vec_IntSize(p) % nWords == 0 );
-    for ( i = 0; i < nObjs; i++ )
-        for ( w = 0; w < nWords; w++ )
-            pArray[2 * nWords * i + w] = p->pArray[nWords * i + w];
-    ABC_FREE( p->pArray );
-    p->pArray = pArray;
-    p->nSize *= 2;
-    p->nCap = p->nSize;
-}
-
-/**Function*************************************************************
-
-  Synopsis    [Prints the results.]
-
-  Description []
-               
-  SideEffects []
-
-  SeeAlso     []
-
-***********************************************************************/
-void Vta_ManAbsPrint( Vta_Man_t * p, int fThis )
-{
-    Vec_Ptr_t * vInfos;
-    Vec_Int_t * vPres;
-    unsigned * pInfo;
-    int CountAll, CountUni;
-    int Entry, i, w, f;
-    // collected used nodes
-    vInfos = Vec_PtrAlloc( 1000 );
-    Vec_IntForEachEntry( p->vAbsAll, Entry, i )
-    {
-        if ( Entry )
-            Vec_PtrPush( vInfos, Vta_ObjAbsNew(p, i) );
-
-        pInfo = Vta_ObjAbsNew(p, i);
-        for ( w = 0; w < p->nWords; w++ )
-            if ( pInfo[w] )
-                break;
-        assert( Entry == (int)(w < p->nWords) );
-    }
-    printf( "%d", Vec_PtrSize(vInfos) );
-    // print results for used nodes
-    vPres = Vec_IntStart( Vec_PtrSize(vInfos) );
-    for ( f = 0; f <= fThis; f++ )
-    {
-        CountAll = CountUni = 0;
-        Vec_PtrForEachEntry( unsigned *, vInfos, pInfo, i )
-        {
-            if ( !Gia_InfoHasBit(pInfo, f) )
-                continue;
-            CountAll++;
-            if ( Vec_IntEntry(vPres, i) )
-                continue;
-            CountUni++;
-            Vec_IntWriteEntry( vPres, i, 1 );
-        }
-        printf( "  %d(%d)", CountAll, CountUni );
-    }
-    printf( "\n" );
-    Vec_PtrFree( vInfos );
-    Vec_IntFree( vPres );
-}
-
-/**Function*************************************************************
-
   Synopsis    []
 
   Description []
@@ -868,8 +977,8 @@ static inline void Vga_ManUnroll_rec( Vta_Man_t * p, int iObj, int iFrame )
     int iVar;
     Gia_Obj_t * pObj;
     Vta_Obj_t * pThis;
-    if ( !Gia_InfoHasBit( Vta_ObjAbsOld(p, iObj), iFrame ) )
-        return;
+//    if ( !Gia_InfoHasBit( Vta_ObjAbsOld(p, iObj), iFrame ) )
+//        return;
     pThis = Vga_ManFindOrAdd( p, iObj, iFrame );
     if ( !pThis->fNew )
         return;
@@ -906,6 +1015,65 @@ static inline void Vga_ManUnroll_rec( Vta_Man_t * p, int iObj, int iFrame )
 
 /**Function*************************************************************
 
+  Synopsis    []
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Vta_ManAbsPrintFrame( Vta_Man_t * p, Vec_Int_t * vCore, int iFrame )
+{
+    int i, k, iObj, Entry;
+    unsigned * pInfo, * pCountAll, * pCountUni;
+    // print info about frames
+    pCountAll = ABC_CALLOC( int, iFrame + 2 );
+    pCountUni = ABC_CALLOC( int, iFrame + 2 );
+    Vec_IntForEachEntry( vCore, Entry, i )
+    {
+        iObj   = (Entry &  p->nObjMask);
+        iFrame = (Entry >> p->nObjBits);
+        pInfo  = (unsigned *)Vec_IntEntryP( p->vSeens, p->nWords * iObj );
+        if ( Gia_InfoHasBit(pInfo, iFrame) == 0 )
+        {
+            Gia_InfoSetBit( pInfo, iFrame );
+            pCountUni[iFrame+1]++;
+            pCountUni[0]++;
+        }
+        pCountAll[iFrame+1]++;
+        pCountAll[0]++;
+
+        printf( "%5d%5d  ", pCountAll[0], pCountUni[0] ); 
+        for ( k = 0; k <= iFrame; k++ )
+            printf( "%5d%5d  ", pCountAll[k+1], pCountUni[k+1] ); 
+        printf( "\n" );
+    }
+    ABC_FREE( pCountAll );
+    ABC_FREE( pCountUni );
+}
+
+/**Function*************************************************************
+
+  Synopsis    []
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Vga_ManAddOneSlice( Vta_Man_t * p, Vec_Int_t * vOne, int Lift )
+{
+    int Entry, i;
+    Vec_IntForEachEntry( vOne, Entry, i )
+        Vga_ManFindOrAdd( p, Entry & p->nObjMask, (Entry >> p->nObjBits) + Lift );
+}
+
+/**Function*************************************************************
+
   Synopsis    [Collect nodes/flops involved in different timeframes.]
 
   Description []
@@ -915,58 +1083,71 @@ static inline void Vga_ManUnroll_rec( Vta_Man_t * p, int iObj, int iFrame )
   SeeAlso     []
 
 ***********************************************************************/
-void Gia_VtaTest( Gia_Man_t * pAig, int nFramesMax, int nConfMax, int nTimeMax, int fVerbose )
+void Gia_VtaTest( Gia_Man_t * pAig, int nFramesStart, int nFramesMax, int nConfMax, int nTimeMax, int fVerbose )
 {
     Vta_Man_t * p;
     Gia_Obj_t * pObj;
-    Abc_Cex_t * pCex;
-    Vec_Int_t * vCore;
-    Vec_Int_t * vAbs = NULL;
-    int f, i, iObjPrev, RetValue, Entry;
+    Abc_Cex_t * pCex = NULL;
+    Vec_Int_t * vCore, * vOne;
+    int f, i, iObjPrev, RetValue, Limit;
     assert( Gia_ManPoNum(pAig) == 1 );
     pObj = Gia_ManPo( pAig, 0 );
     // start the manager
-    p = Vga_ManStart( pAig, vAbs, nFramesMax, nConfMax, nTimeMax, fVerbose );
-    // iteragte though time frames
+    p = Vga_ManStart( pAig, nFramesStart, nFramesMax, nConfMax, nTimeMax, fVerbose );
+    // perform initial abstraction
     for ( f = 0; f < nFramesMax; f++ )
     {
+        if ( f == p->nWords * 32 )
+            p->nWords = Vec_IntDoubleWidth( p->vSeens, p->nWords );
         p->iFrame = f;
         if ( fVerbose )
             printf( "Frame %4d : ", f );
-        if ( p->nWords * 32 == f )
-        {
-            Vec_IntDoubleWidth( vAbs, p->nWords );
-            p->nWords *= 2;
-        }
-
-        if ( f < p->nFramesS )
+        if ( f < nFramesStart )
         {
-            // unroll and create clauses
+            // load the time frame
             iObjPrev = p->nObjs;
-            assert( Gia_InfoHasBit( Vta_ObjAbsOld(p, Gia_ObjFaninId0p(p->pGia, pObj)), f ) );
-            Vga_ManUnroll_rec( p, Gia_ObjFaninId0p(p->pGia, pObj), f );
+            vOne = Vec_PtrEntry( p->vFrames, f );
+            Vga_ManAddOneSlice( p, vOne, 0 );
             for ( i = iObjPrev; i < p->nObjs; i++ )
                 Vga_ManAddClausesOne( p, Vta_ManObj(p, i) );
             // run SAT solver
             vCore = Vta_ManUnsatCore( p->vCla2Var, p->pSat, nConfMax, fVerbose, &RetValue );
             if ( vCore == NULL && RetValue == 0 )
+            {
+                // make sure, there was no initial abstraction (otherwise, it was invalid)
+                assert( pAig->vObjClasses == NULL );
+                // derive counter-example
                 pCex = NULL;
+                break;
+            }
         }
         else
         {
-            // consider the last p->nFramesS/2 cores
-
-            // add them for the last time frame
+            break;
 
+            Limit = Abc_MinInt(3, nFramesStart);
+            // load the time frame
+            iObjPrev = p->nObjs;
+            for ( i = 1; i <= Limit; i++ )
+            {
+                vOne = Vec_PtrEntry( p->vCores, f-i );
+                Vga_ManAddOneSlice( p, vOne, i );
+            }
+            for ( i = iObjPrev; i < p->nObjs; i++ )
+                Vga_ManAddClausesOne( p, Vta_ManObj(p, i) );
             // iterate as long as there are counter-examples
             while ( 1 )
             {
                 vCore = Vta_ManUnsatCore( p->vCla2Var, p->pSat, nConfMax, fVerbose, &RetValue );
+                if ( RetValue ) // resource limit is reached
+                {
+                    assert( vCore == NULL );
+                    break;
+                }
                 if ( vCore != NULL )
                 {
                     // unroll the solver, add the core
-
-                    // return and dobule check
+                    // return and double check
                     break;
                 }
                 pCex = Vta_ManRefineAbstraction( p );
@@ -974,7 +1155,6 @@ void Gia_VtaTest( Gia_Man_t * pAig, int nFramesMax, int nConfMax, int nTimeMax,
                     break;
             }
         }
-
         if ( pCex != NULL )
         {
             // the problem is SAT
@@ -983,27 +1163,18 @@ void Gia_VtaTest( Gia_Man_t * pAig, int nFramesMax, int nConfMax, int nTimeMax,
         {
             // resource limit is reached
         }
-
-        // add core to storage
-        Vec_IntForEachEntry( vCore, Entry, i )
-        {
-            Vta_Obj_t * pThis = Vta_ManObj( p, Entry );
-            unsigned * pInfo = Vta_ObjAbsNew( p, pThis->iObj );
-            Vec_IntWriteEntry( p->vAbsAll, pThis->iObj, 1 );
-            Gia_InfoSetBit( pInfo, pThis->iFrame );
-        }
-//        Vec_IntFree( vCore );
+        // add the core
         Vec_PtrPush( p->vCores, vCore );
         // print the result
         if ( fVerbose )
-            Vta_ManAbsPrint( p, f );
+            Vta_ManAbsPrintFrame( p, vCore, f );
     }
-
-    vAbs = p->vAbsNew; p->vAbsNew = NULL;
+    assert( Vec_PtrSize(p->vCores) > 0 );
+    if ( pAig->vObjClasses != NULL )
+        printf( "Replacing the old abstraction by a new one.\n" );
+    Vec_IntFreeP( &pAig->vObjClasses );
+    pAig->vObjClasses = Vta_ManFramesToAbs( (Vec_Vec_t *)p->vCores );
     Vga_ManStop( p );
-
-    // print statistics about the core
-    Vec_IntFree( vAbs );
 }
 
 ////////////////////////////////////////////////////////////////////////
diff --git a/src/aig/gia/giaAiger.c b/src/aig/gia/giaAiger.c
index ea3fa2ef..db194c69 100644
--- a/src/aig/gia/giaAiger.c
+++ b/src/aig/gia/giaAiger.c
@@ -567,6 +567,14 @@ Gia_Man_t * Gia_ReadAiger2( char * pFileName, int fCheck )
             pNew->vGateClasses = Vec_IntStart( Gia_ManObjNum(pNew) );
             Gia_ReadFlopClasses( &pCur, pNew->vGateClasses, Gia_ManObjNum(pNew) );
         }
+        if ( *pCur == 'v' )
+        {
+            pCur++;
+            // read object classes
+            pNew->vObjClasses = Vec_IntStart( Gia_ReadInt(pCur)/4 ); pCur += 4;
+            memcpy( Vec_IntArray(pNew->vObjClasses), pCur, 4*Vec_IntSize(pNew->vObjClasses) );
+            pCur += 4*Vec_IntSize(pNew->vObjClasses);
+        }
         if ( *pCur == 'm' )
         {
             pCur++;
@@ -618,7 +626,6 @@ Gia_Man_t * Gia_ReadAiger2( char * pFileName, int fCheck )
     return pNew;
 }
 
-
 /**Function*************************************************************
 
   Synopsis    [Reads the AIG in the binary AIGER format.]
@@ -833,6 +840,14 @@ Gia_Man_t * Gia_ReadAigerFromMemory( char * pContents, int nFileSize, int fCheck
             pNew->vGateClasses = Vec_IntStart( Gia_ManObjNum(pNew) );
             Gia_ReadFlopClasses( &pCur, pNew->vGateClasses, Gia_ManObjNum(pNew) );
         }
+        if ( *pCur == 'v' )
+        {
+            pCur++;
+            // read object classes
+            pNew->vObjClasses = Vec_IntStart( Gia_ReadInt(pCur)/4 ); pCur += 4;
+            memcpy( Vec_IntArray(pNew->vObjClasses), pCur, 4*Vec_IntSize(pNew->vObjClasses) );
+            pCur += 4*Vec_IntSize(pNew->vObjClasses);
+        }
         if ( *pCur == 'm' )
         {
             pCur++;
@@ -1024,14 +1039,26 @@ Gia_Man_t * Gia_ReadAigerFromMemory( char * pContents, int nFileSize, int fCheck
     }
 
     {
-        Vec_Int_t * vFlopMap, * vGateMap;
+        Vec_Int_t * vFlopMap, * vGateMap, * vObjMap;
         vFlopMap = pNew->vFlopClasses; pNew->vFlopClasses = NULL;
         vGateMap = pNew->vGateClasses; pNew->vGateClasses = NULL;
+        vObjMap  = pNew->vObjClasses;  pNew->vObjClasses  = NULL;
         pNew = Gia_ManCleanup( pTemp = pNew );
         Gia_ManStop( pTemp );
         pNew->vFlopClasses = vFlopMap;
         pNew->vGateClasses = vGateMap;
+        pNew->vObjClasses  = vObjMap;
+    }
+/*
+    {
+        extern Vec_Int_t * Vta_ManFramesToAbs( Vec_Vec_t * vFrames );
+        extern Vec_Ptr_t * Vta_ManAbsToFrames( Vec_Int_t * vAbs );
+        Vec_Vec_t * vAbs = (Vec_Vec_t *)Gia_ManUnrollAbs( pNew );
+        assert( pNew->vObjClasses == NULL );
+        pNew->vObjClasses = Vta_ManFramesToAbs( vAbs );
+        Vec_VecFree( vAbs );
     }
+*/
     return pNew;
 }
 
@@ -1461,6 +1488,16 @@ void Gia_WriteAiger( Gia_Man_t * pInit, char * pFileName, int fWriteSymbols, int
         fwrite( Buffer, 1, 4, pFile );
         fwrite( Vec_IntArray(p->vGateClasses), 1, nSize, pFile );
     }
+    // write object classes
+    if ( p->vObjClasses )
+    {
+        unsigned char Buffer[10];
+        int nSize = 4*Vec_IntSize(p->vObjClasses);
+        Gia_WriteInt( Buffer, nSize );
+        fprintf( pFile, "v" );
+        fwrite( Buffer, 1, 4, pFile );
+        fwrite( Vec_IntArray(p->vObjClasses), 1, nSize, pFile );
+    }
     // write mapping
     if ( p->pMapping )
     {
diff --git a/src/aig/gia/giaFrames.c b/src/aig/gia/giaFrames.c
index 06bea871..bee181c3 100644
--- a/src/aig/gia/giaFrames.c
+++ b/src/aig/gia/giaFrames.c
@@ -72,7 +72,7 @@ struct Gia_ManUnr_t_
   SeeAlso     []
 
 ***********************************************************************/
-void Gia_ManUnrDup_rec( Gia_Man_t * pNew, Gia_Obj_t * pObj, int Id ) 
+void Gia_ManUnrollDup_rec( Gia_Man_t * pNew, Gia_Obj_t * pObj, int Id ) 
 {
     if ( ~pObj->Value )
         return;
@@ -80,13 +80,13 @@ void Gia_ManUnrDup_rec( Gia_Man_t * pNew, Gia_Obj_t * pObj, int Id )
         pObj->Value = Gia_ManAppendCi(pNew);
     else if ( Gia_ObjIsCo(pObj) )
     {
-        Gia_ManUnrDup_rec( pNew, Gia_ObjFanin0(pObj), Gia_ObjFaninId0(pObj, Id) );
+        Gia_ManUnrollDup_rec( pNew, Gia_ObjFanin0(pObj), Gia_ObjFaninId0(pObj, Id) );
         pObj->Value = Gia_ManAppendCo( pNew, Gia_ObjFanin0Copy(pObj) );
     }
     else if ( Gia_ObjIsAnd(pObj) )
     {
-        Gia_ManUnrDup_rec( pNew, Gia_ObjFanin0(pObj), Gia_ObjFaninId0(pObj, Id) );
-        Gia_ManUnrDup_rec( pNew, Gia_ObjFanin1(pObj), Gia_ObjFaninId1(pObj, Id) );
+        Gia_ManUnrollDup_rec( pNew, Gia_ObjFanin0(pObj), Gia_ObjFaninId0(pObj, Id) );
+        Gia_ManUnrollDup_rec( pNew, Gia_ObjFanin1(pObj), Gia_ObjFaninId1(pObj, Id) );
         pObj->Value = Gia_ManAppendAnd( pNew, Gia_ObjFanin0Copy(pObj), Gia_ObjFanin1Copy(pObj) );
     }
     else assert( 0 );
@@ -104,7 +104,7 @@ void Gia_ManUnrDup_rec( Gia_Man_t * pNew, Gia_Obj_t * pObj, int Id )
   SeeAlso     []
 
 ***********************************************************************/
-Gia_Man_t * Gia_ManUnrDup( Gia_Man_t * p, Vec_Int_t * vLimit )  
+Gia_Man_t * Gia_ManUnrollDup( Gia_Man_t * p, Vec_Int_t * vLimit )  
 {
     Gia_Man_t * pNew;
     Gia_Obj_t * pObj;
@@ -120,7 +120,7 @@ Gia_Man_t * Gia_ManUnrDup( Gia_Man_t * p, Vec_Int_t * vLimit )
  
     // create first class
     Gia_ManForEachPo( p, pObj, i )
-        Gia_ManUnrDup_rec( pNew, pObj, Gia_ObjId(p, pObj) );
+        Gia_ManUnrollDup_rec( pNew, pObj, Gia_ObjId(p, pObj) );
     Vec_IntPush( vLimit, Gia_ManObjNum(pNew) );
 
     // create next classes
@@ -133,7 +133,7 @@ Gia_Man_t * Gia_ManUnrDup( Gia_Man_t * p, Vec_Int_t * vLimit )
         {
             pObj = Gia_ObjRoToRi(p, pObj);
             assert( !~pObj->Value );
-            Gia_ManUnrDup_rec( pNew, pObj, Gia_ObjId(p, pObj) );
+            Gia_ManUnrollDup_rec( pNew, pObj, Gia_ObjId(p, pObj) );
         }
     }
     Gia_ManSetRegNum( pNew, 0 );
@@ -142,6 +142,73 @@ Gia_Man_t * Gia_ManUnrDup( Gia_Man_t * p, Vec_Int_t * vLimit )
 
 /**Function*************************************************************
 
+  Synopsis    [Duplicates AIG for unrolling.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Vec_Ptr_t * Gia_ManUnrollAbs( Gia_Man_t * p, int nFrames )  
+{
+    int fVerbose = 0;
+    Vec_Ptr_t * vFrames;
+    Vec_Int_t * vLimit, * vOne;
+    Gia_Man_t * pNew;
+    Gia_Obj_t * pObj;
+    int nObjBits, nObjMask;
+    int f, fMax, k, Entry, Prev, iStart, iStop, Size;
+    // get the bitmasks
+    nObjBits = Gia_Base2Log( Gia_ManObjNum(p) );
+    nObjMask = (1 << nObjBits) - 1;
+    assert( Gia_ManObjNum(p) <= nObjMask );
+    // derive the tents
+    vLimit = Vec_IntAlloc( 1000 );
+    pNew = Gia_ManUnrollDup( p, vLimit );
+    // debug printout
+    if ( fVerbose )
+    {
+        Prev = 1;
+        printf( "Tents: " );
+        Vec_IntForEachEntryStart( vLimit, Entry, k, 1 )
+            printf( "%d=%d ", k, Entry-Prev ), Prev = Entry;
+        printf( "  Unused=%d", Gia_ManObjNum(p) - Gia_ManObjNum(pNew) );
+        printf( "\n" );
+    }
+    // create abstraction
+    vFrames = Vec_PtrAlloc( Vec_IntSize(vLimit) );
+    for ( fMax = 0; fMax < nFrames; fMax++ )
+    {
+        Size = (fMax+1 < Vec_IntSize(vLimit)) ? Vec_IntEntry(vLimit, fMax+1) : Gia_ManObjNum(pNew);
+        vOne = Vec_IntAlloc( Size );
+        for ( f = 0; f <= fMax; f++ )
+        {
+            iStart = (f   < Vec_IntSize(vLimit)) ? Vec_IntEntry(vLimit, f  ) : 0;
+            iStop  = (f+1 < Vec_IntSize(vLimit)) ? Vec_IntEntry(vLimit, f+1) : 0;
+            for ( k = iStop - 1; k >= iStart; k-- )
+            {
+                pObj  = Gia_ManObj(pNew, k);
+                if ( Gia_ObjIsCo(pObj) )
+                    continue;
+                assert( Gia_ObjIsCi(pObj) || Gia_ObjIsAnd(pObj) );
+                Entry = ((fMax-f) << nObjBits) | pObj->Value;
+                Vec_IntPush( vOne, Entry );
+//                printf( "%d ", Gia_ManObj(pNew, k)->Value );
+            }
+//            printf( "\n" );
+        }
+        Vec_PtrPush( vFrames, vOne );
+        assert( Vec_IntSize(vOne) <= Size - 1 );
+    }
+    Vec_IntFree( vLimit );
+    Gia_ManStop( pNew );
+    return vFrames;
+}
+
+/**Function*************************************************************
+
   Synopsis    [Creates manager.]
 
   Description []
@@ -163,7 +230,7 @@ Gia_ManUnr_t * Gia_ManUnrStart( Gia_Man_t * pAig, Gia_ParFra_t * pPars )
     p->pPars  = pPars;
     // create order
     p->vLimit = Vec_IntAlloc( 0 );
-    p->pOrder = Gia_ManUnrDup( pAig, p->vLimit );
+    p->pOrder = Gia_ManUnrollDup( pAig, p->vLimit );
 /*
     Vec_IntForEachEntryStart( p->vLimit, Shift, i, 1 )
         printf( "%d=%d ", i, Shift-Vec_IntEntry(p->vLimit, i-1) );
diff --git a/src/aig/gia/giaMan.c b/src/aig/gia/giaMan.c
index 8b72e0b6..0acd547d 100644
--- a/src/aig/gia/giaMan.c
+++ b/src/aig/gia/giaMan.c
@@ -83,6 +83,7 @@ void Gia_ManStop( Gia_Man_t * p )
     Vec_IntFreeP( &p->vUserFfIds );
     Vec_IntFreeP( &p->vFlopClasses );
     Vec_IntFreeP( &p->vGateClasses );
+    Vec_IntFreeP( &p->vObjClasses );
     Vec_IntFreeP( &p->vLevels );
     Vec_IntFreeP( &p->vTruths );
     Vec_IntFree( p->vCis );
@@ -256,6 +257,71 @@ void Gia_ManPrintGateClasses( Gia_Man_t * p )
   SeeAlso     []
 
 ***********************************************************************/
+void Gia_ManPrintObjClasses( Gia_Man_t * p )
+{
+    Vec_Int_t * vSeens;  // objects seen so far
+    Vec_Int_t * vAbs = p->vObjClasses;
+    int i, k, Entry, iStart, iStop, nFrames;
+    int nObjBits, nObjMask, iObj, iFrame, nWords;
+    unsigned * pInfo, * pCountAll, * pCountUni;
+    if ( vAbs == NULL )
+        return;
+    nFrames = Vec_IntEntry( vAbs, 0 );
+    assert( Vec_IntEntry(vAbs, nFrames+1) == Vec_IntSize(vAbs) );
+    pCountAll = ABC_ALLOC( int, nFrames + 1 );
+    pCountUni = ABC_ALLOC( int, nFrames + 1 );
+    // start storage for seen objects
+    nWords = Gia_BitWordNum( nFrames );
+    vSeens = Vec_IntStart( Gia_ManObjNum(p) * nWords );
+    // get the bitmasks
+    nObjBits = Gia_Base2Log( Gia_ManObjNum(p) );
+    nObjMask = (1 << nObjBits) - 1;
+    assert( Gia_ManObjNum(p) <= nObjMask );
+    // print info about frames
+    for ( i = 0; i < nFrames; i++ )
+    {
+        iStart = Vec_IntEntry( vAbs, i+1 );
+        iStop  = Vec_IntEntry( vAbs, i+2 );
+        memset( pCountAll, 0, sizeof(int) * (nFrames + 1) );
+        memset( pCountUni, 0, sizeof(int) * (nFrames + 1) );
+        Vec_IntForEachEntryStartStop( vAbs, Entry, k, iStart, iStop )
+        {
+            iObj   = (Entry &  nObjMask);
+            iFrame = (Entry >> nObjBits);
+            pInfo  = (unsigned *)Vec_IntEntryP( vSeens, nWords * iObj );
+            if ( Gia_InfoHasBit(pInfo, iFrame) == 0 )
+            {
+                Gia_InfoSetBit( pInfo, iFrame );
+                pCountUni[iFrame+1]++;
+                pCountUni[0]++;
+            }
+            pCountAll[iFrame+1]++;
+            pCountAll[0]++;
+        }
+        assert( pCountAll[0] == (unsigned)(iStop - iStart) );
+        printf( "%5d%5d  ", pCountAll[0], pCountUni[0] ); 
+        for ( k = 0; k < nFrames; k++ )
+            if ( k <= i )
+                printf( "%5d%5d  ", pCountAll[k+1], pCountUni[k+1] ); 
+        printf( "\n" );
+    }
+    assert( iStop == Vec_IntSize(vAbs) );
+    Vec_IntFree( vSeens );
+    ABC_FREE( pCountAll );
+    ABC_FREE( pCountUni );
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Prints stats for the AIG.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
 void Gia_ManPrintPlacement( Gia_Man_t * p )
 {
     int i, nFixed = 0, nUndef = 0;
@@ -315,6 +381,7 @@ void Gia_ManPrintStats( Gia_Man_t * p, int fSwitch )
     // print register classes
     Gia_ManPrintFlopClasses( p );
     Gia_ManPrintGateClasses( p );
+    Gia_ManPrintObjClasses( p );
 }
 
 /**Function*************************************************************
diff --git a/src/base/abci/abc.c b/src/base/abci/abc.c
index f1927d93..13cfad9c 100644
--- a/src/base/abci/abc.c
+++ b/src/base/abci/abc.c
@@ -30329,8 +30329,8 @@ int Abc_CommandAbc9Test( Abc_Frame_t * pAbc, int argc, char ** argv )
     int c, fVerbose = 0;
     int fSwitch = 0;
 //    extern Gia_Man_t * Gia_VtaTest( Gia_Man_t * p );
-    extern void Gia_VtaTest( Gia_Man_t * p, int nFramesMax, int nConfMax, int nTimeMax, int fVerbose );
-    extern int Gia_ManSuppSizeTest( Gia_Man_t * p );
+//    extern int Gia_ManSuppSizeTest( Gia_Man_t * p );
+    extern void Gia_VtaTest( Gia_Man_t * p, int nFramesStart, int nFramesMax, int nConfMax, int nTimeMax, int fVerbose );
 
     Extra_UtilGetoptReset();
     while ( ( c = Extra_UtilGetopt( argc, argv, "svh" ) ) != EOF )
@@ -30364,14 +30364,12 @@ int Abc_CommandAbc9Test( Abc_Frame_t * pAbc, int argc, char ** argv )
 //    pAbc->pGia = Gia_ManDupSelf( pTemp = pAbc->pGia );
 //    pAbc->pGia = Gia_ManRemoveEnables( pTemp = pAbc->pGia );
 //    Cbs_ManSolveTest( pAbc->pGia );
-
 //    pAbc->pGia = Gia_VtaTest( pTemp = pAbc->pGia );
 //    Gia_ManStopP( &pTemp );
-//    Gia_VtaTest( pAbc->pGia, 100000, 0, 0, 1 );
-    Gia_ManSuppSizeTest( pAbc->pGia );
+//    Gia_ManSuppSizeTest( pAbc->pGia );
 
+    Gia_VtaTest( pAbc->pGia, 10, 100000, 0, 0, 1 );
     return 0;
-
 usage:
     Abc_Print( -2, "usage: &test [-svh]\n" );
     Abc_Print( -2, "\t        testing various procedures\n" );
diff --git a/src/misc/vec/vecVec.h b/src/misc/vec/vecVec.h
index 5405e7f4..91713291 100644
--- a/src/misc/vec/vecVec.h
+++ b/src/misc/vec/vecVec.h
@@ -586,6 +586,29 @@ static inline void Vec_VecSort( Vec_Vec_t * p, int fReverse )
                 (int (*)(const void *, const void *)) Vec_VecSortCompare1 );
 }
 
+/**Function*************************************************************
+
+  Synopsis    []
+
+  Description []
+  
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+static inline void Vec_VecPrintInt( Vec_Vec_t * p )
+{
+    int i, k, Entry;
+    printf( "Integers by level" );
+    Vec_VecForEachEntryInt( p, Entry, i, k )
+    {
+        if ( k == 0 )
+            printf( "\n%3d : ", i );
+        printf( "%6d ", Entry );
+    }
+    printf( "\n" );
+}
 
 
 ABC_NAMESPACE_HEADER_END