Version abc80130_2

1 files changed, 1952 insertions, 0 deletions

diff --git a/src/base/abci/abcResub.c b/src/base/abci/abcResub.c
new file mode 100644
index 00000000..a2b23c0c
--- /dev/null
+++ b/src/base/abci/abcResub.c
@@ -0,0 +1,1952 @@
+/**CFile****************************************************************
+
+  FileName    [abcResub.c]
+
+  SystemName  [ABC: Logic synthesis and verification system.]
+
+  PackageName [Network and node package.]
+
+  Synopsis    [Resubstitution manager.]
+
+  Author      [Alan Mishchenko]
+  
+  Affiliation [UC Berkeley]
+
+  Date        [Ver. 1.0. Started - June 20, 2005.]
+
+  Revision    [$Id: abcResub.c,v 1.00 2005/06/20 00:00:00 alanmi Exp $]
+
+***********************************************************************/
+
+#include "abc.h"
+#include "dec.h"
+ 
+////////////////////////////////////////////////////////////////////////
+///                        DECLARATIONS                              ///
+////////////////////////////////////////////////////////////////////////
+
+#define ABC_RS_DIV1_MAX    150   // the max number of divisors to consider
+#define ABC_RS_DIV2_MAX    500   // the max number of pair-wise divisors to consider
+
+typedef struct Abc_ManRes_t_ Abc_ManRes_t;
+struct Abc_ManRes_t_
+{
+    // paramers
+    int                nLeavesMax; // the max number of leaves in the cone
+    int                nDivsMax;   // the max number of divisors in the cone
+    // representation of the cone
+    Abc_Obj_t *        pRoot;      // the root of the cone
+    int                nLeaves;    // the number of leaves
+    int                nDivs;      // the number of all divisor (including leaves)
+    int                nMffc;      // the size of MFFC
+    int                nLastGain;  // the gain the number of nodes
+    Vec_Ptr_t *        vDivs;      // the divisors
+    // representation of the simulation info
+    int                nBits;      // the number of simulation bits
+    int                nWords;     // the number of unsigneds for siminfo
+    Vec_Ptr_t        * vSims;      // simulation info
+    unsigned         * pInfo;      // pointer to simulation info
+    // observability don't-cares
+    unsigned *         pCareSet;
+    // internal divisor storage
+    Vec_Ptr_t        * vDivs1UP;   // the single-node unate divisors
+    Vec_Ptr_t        * vDivs1UN;   // the single-node unate divisors
+    Vec_Ptr_t        * vDivs1B;    // the single-node binate divisors
+    Vec_Ptr_t        * vDivs2UP0;  // the double-node unate divisors
+    Vec_Ptr_t        * vDivs2UP1;  // the double-node unate divisors
+    Vec_Ptr_t        * vDivs2UN0;  // the double-node unate divisors
+    Vec_Ptr_t        * vDivs2UN1;  // the double-node unate divisors
+    // other data
+    Vec_Ptr_t        * vTemp;      // temporary array of nodes
+    // runtime statistics
+    int                timeCut;
+    int                timeTruth;
+    int                timeRes;
+    int                timeDiv;
+    int                timeMffc;
+    int                timeSim;
+    int                timeRes1;
+    int                timeResD;
+    int                timeRes2;
+    int                timeRes3;
+    int                timeNtk;
+    int                timeTotal;
+    // improvement statistics
+    int                nUsedNodeC;
+    int                nUsedNode0;
+    int                nUsedNode1Or;
+    int                nUsedNode1And;
+    int                nUsedNode2Or;
+    int                nUsedNode2And;
+    int                nUsedNode2OrAnd;
+    int                nUsedNode2AndOr;
+    int                nUsedNode3OrAnd;
+    int                nUsedNode3AndOr;
+    int                nUsedNodeTotal;
+    int                nTotalDivs;
+    int                nTotalLeaves;
+    int                nTotalGain;
+    int                nNodesBeg;
+    int                nNodesEnd;
+};
+
+// external procedures
+static Abc_ManRes_t* Abc_ManResubStart( int nLeavesMax, int nDivsMax );
+static void          Abc_ManResubStop( Abc_ManRes_t * p );
+static Dec_Graph_t * Abc_ManResubEval( Abc_ManRes_t * p, Abc_Obj_t * pRoot, Vec_Ptr_t * vLeaves, int nSteps, bool fUpdateLevel, int fVerbose );
+static void          Abc_ManResubCleanup( Abc_ManRes_t * p );
+static void          Abc_ManResubPrint( Abc_ManRes_t * p );
+
+// other procedures
+static int           Abc_ManResubCollectDivs( Abc_ManRes_t * p, Abc_Obj_t * pRoot, Vec_Ptr_t * vLeaves, int Required );
+static void          Abc_ManResubSimulate( Vec_Ptr_t * vDivs, int nLeaves, Vec_Ptr_t * vSims, int nLeavesMax, int nWords );
+static void          Abc_ManResubPrintDivs( Abc_ManRes_t * p, Abc_Obj_t * pRoot, Vec_Ptr_t * vLeaves );
+
+static void          Abc_ManResubDivsS( Abc_ManRes_t * p, int Required );
+static void          Abc_ManResubDivsD( Abc_ManRes_t * p, int Required );
+static Dec_Graph_t * Abc_ManResubQuit( Abc_ManRes_t * p );
+static Dec_Graph_t * Abc_ManResubDivs0( Abc_ManRes_t * p );
+static Dec_Graph_t * Abc_ManResubDivs1( Abc_ManRes_t * p, int Required );
+static Dec_Graph_t * Abc_ManResubDivs12( Abc_ManRes_t * p, int Required );
+static Dec_Graph_t * Abc_ManResubDivs2( Abc_ManRes_t * p, int Required );
+static Dec_Graph_t * Abc_ManResubDivs3( Abc_ManRes_t * p, int Required );
+
+static Vec_Ptr_t *   Abc_CutFactorLarge( Abc_Obj_t * pNode, int nLeavesMax );
+static int           Abc_CutVolumeCheck( Abc_Obj_t * pNode, Vec_Ptr_t * vLeaves );
+
+// don't-care manager
+extern void * Abc_NtkDontCareAlloc( int nVarsMax, int nLevels, int fVerbose, int fVeryVerbose );
+extern void Abc_NtkDontCareClear( void * p );
+extern void Abc_NtkDontCareFree( void * p );
+extern int Abc_NtkDontCareCompute( void * p, Abc_Obj_t * pNode, Vec_Ptr_t * vLeaves, unsigned * puTruth );
+
+extern int s_ResubTime;
+
+////////////////////////////////////////////////////////////////////////
+///                     FUNCTION DEFINITIONS                         ///
+////////////////////////////////////////////////////////////////////////
+
+/**Function*************************************************************
+
+  Synopsis    [Performs incremental resynthesis of the AIG.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Abc_NtkResubstitute( Abc_Ntk_t * pNtk, int nCutMax, int nStepsMax, int nLevelsOdc, bool fUpdateLevel, bool fVerbose, bool fVeryVerbose )
+{
+    extern void           Dec_GraphUpdateNetwork( Abc_Obj_t * pRoot, Dec_Graph_t * pGraph, bool fUpdateLevel, int nGain );
+    ProgressBar * pProgress;
+    Abc_ManRes_t * pManRes;
+    Abc_ManCut_t * pManCut;
+    void * pManOdc = NULL;
+    Dec_Graph_t * pFForm;
+    Vec_Ptr_t * vLeaves;
+    Abc_Obj_t * pNode;
+    int clk, clkStart = clock();
+    int i, nNodes;
+
+    assert( Abc_NtkIsStrash(pNtk) );
+
+    // cleanup the AIG
+    Abc_AigCleanup(pNtk->pManFunc);
+    // start the managers
+    pManCut = Abc_NtkManCutStart( nCutMax, 100000, 100000, 100000 );
+    pManRes = Abc_ManResubStart( nCutMax, ABC_RS_DIV1_MAX );
+    if ( nLevelsOdc > 0 )
+    pManOdc = Abc_NtkDontCareAlloc( nCutMax, nLevelsOdc, fVerbose, fVeryVerbose );
+
+    // compute the reverse levels if level update is requested
+    if ( fUpdateLevel )
+        Abc_NtkStartReverseLevels( pNtk, 0 );
+
+    if ( Abc_NtkLatchNum(pNtk) )
+        Abc_NtkForEachLatch(pNtk, pNode, i)
+            pNode->pNext = pNode->pData;
+
+    // resynthesize each node once
+    pManRes->nNodesBeg = Abc_NtkNodeNum(pNtk);
+    nNodes = Abc_NtkObjNumMax(pNtk);
+    pProgress = Extra_ProgressBarStart( stdout, nNodes );
+    Abc_NtkForEachNode( pNtk, pNode, i )
+    {
+        Extra_ProgressBarUpdate( pProgress, i, NULL );
+        // skip the constant node
+//        if ( Abc_NodeIsConst(pNode) )
+//            continue;
+        // skip persistant nodes
+        if ( Abc_NodeIsPersistant(pNode) )
+            continue;
+        // skip the nodes with many fanouts
+        if ( Abc_ObjFanoutNum(pNode) > 1000 )
+            continue;
+        // stop if all nodes have been tried once
+        if ( i >= nNodes )
+            break;
+
+        // compute a reconvergence-driven cut
+clk = clock();
+        vLeaves = Abc_NodeFindCut( pManCut, pNode, 0 );
+//        vLeaves = Abc_CutFactorLarge( pNode, nCutMax );
+pManRes->timeCut += clock() - clk;
+/*
+        if ( fVerbose && vLeaves )
+        printf( "Node %6d : Leaves = %3d. Volume = %3d.\n", pNode->Id, Vec_PtrSize(vLeaves), Abc_CutVolumeCheck(pNode, vLeaves) );
+        if ( vLeaves == NULL )
+            continue;
+*/
+        // get the don't-cares
+        if ( pManOdc )
+        {
+clk = clock();
+            Abc_NtkDontCareClear( pManOdc );
+            Abc_NtkDontCareCompute( pManOdc, pNode, vLeaves, pManRes->pCareSet );
+pManRes->timeTruth += clock() - clk;
+        }
+
+        // evaluate this cut
+clk = clock();
+        pFForm = Abc_ManResubEval( pManRes, pNode, vLeaves, nStepsMax, fUpdateLevel, fVerbose );
+//        Vec_PtrFree( vLeaves );
+//        Abc_ManResubCleanup( pManRes );
+pManRes->timeRes += clock() - clk;
+        if ( pFForm == NULL )
+            continue;
+        pManRes->nTotalGain += pManRes->nLastGain;
+/*
+        if ( pManRes->nLeaves == 4 && pManRes->nMffc == 2 && pManRes->nLastGain == 1 )
+        {
+            printf( "%6d :  L = %2d. V = %2d. Mffc = %2d. Divs = %3d.   Up = %3d. Un = %3d. B = %3d.\n", 
+                   pNode->Id, pManRes->nLeaves, Abc_CutVolumeCheck(pNode, vLeaves), pManRes->nMffc, pManRes->nDivs, 
+                   pManRes->vDivs1UP->nSize, pManRes->vDivs1UN->nSize, pManRes->vDivs1B->nSize );
+            Abc_ManResubPrintDivs( pManRes, pNode, vLeaves );
+        }
+*/
+        // acceptable replacement found, update the graph
+clk = clock();
+        Dec_GraphUpdateNetwork( pNode, pFForm, fUpdateLevel, pManRes->nLastGain );
+pManRes->timeNtk += clock() - clk;
+        Dec_GraphFree( pFForm );
+    }
+    Extra_ProgressBarStop( pProgress );
+pManRes->timeTotal = clock() - clkStart;
+    pManRes->nNodesEnd = Abc_NtkNodeNum(pNtk);
+
+    // print statistics
+    if ( fVerbose )
+    Abc_ManResubPrint( pManRes );
+
+    // delete the managers
+    Abc_ManResubStop( pManRes );
+    Abc_NtkManCutStop( pManCut );
+    if ( pManOdc ) Abc_NtkDontCareFree( pManOdc );
+
+    // clean the data field
+    Abc_NtkForEachObj( pNtk, pNode, i )
+        pNode->pData = NULL;
+
+    if ( Abc_NtkLatchNum(pNtk) )
+        Abc_NtkForEachLatch(pNtk, pNode, i)
+            pNode->pData = pNode->pNext, pNode->pNext = NULL;
+
+    // put the nodes into the DFS order and reassign their IDs
+    Abc_NtkReassignIds( pNtk );
+//    Abc_AigCheckFaninOrder( pNtk->pManFunc );
+    // fix the levels
+    if ( fUpdateLevel )
+        Abc_NtkStopReverseLevels( pNtk );
+    else
+        Abc_NtkLevel( pNtk );
+    // check
+    if ( !Abc_NtkCheck( pNtk ) )
+    {
+        printf( "Abc_NtkRefactor: The network check has failed.\n" );
+        return 0;
+    }
+s_ResubTime = clock() - clkStart;
+    return 1;
+}
+
+
+
+
+/**Function*************************************************************
+
+  Synopsis    []
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Abc_ManRes_t * Abc_ManResubStart( int nLeavesMax, int nDivsMax )
+{
+    Abc_ManRes_t * p;
+    unsigned * pData;
+    int i, k;
+    assert( sizeof(unsigned) == 4 );
+    p = ALLOC( Abc_ManRes_t, 1 );
+    memset( p, 0, sizeof(Abc_ManRes_t) );
+    p->nLeavesMax = nLeavesMax;
+    p->nDivsMax   = nDivsMax;
+    p->vDivs      = Vec_PtrAlloc( p->nDivsMax );
+    // allocate simulation info
+    p->nBits      = (1 << p->nLeavesMax);
+    p->nWords     = (p->nBits <= 32)? 1 : (p->nBits / 32);
+    p->pInfo      = ALLOC( unsigned, p->nWords * (p->nDivsMax + 1) );
+    memset( p->pInfo, 0, sizeof(unsigned) * p->nWords * p->nLeavesMax );
+    p->vSims      = Vec_PtrAlloc( p->nDivsMax );
+    for ( i = 0; i < p->nDivsMax; i++ )
+        Vec_PtrPush( p->vSims, p->pInfo + i * p->nWords );
+    // assign the care set
+    p->pCareSet  = p->pInfo + p->nDivsMax * p->nWords;
+    Abc_InfoFill( p->pCareSet, p->nWords );
+    // set elementary truth tables
+    for ( k = 0; k < p->nLeavesMax; k++ )
+    {
+        pData = p->vSims->pArray[k];
+        for ( i = 0; i < p->nBits; i++ )
+            if ( i & (1 << k) )
+                pData[i>>5] |= (1 << (i&31));
+    }
+    // create the remaining divisors
+    p->vDivs1UP  = Vec_PtrAlloc( p->nDivsMax );
+    p->vDivs1UN  = Vec_PtrAlloc( p->nDivsMax );
+    p->vDivs1B   = Vec_PtrAlloc( p->nDivsMax );
+    p->vDivs2UP0 = Vec_PtrAlloc( p->nDivsMax );
+    p->vDivs2UP1 = Vec_PtrAlloc( p->nDivsMax );
+    p->vDivs2UN0 = Vec_PtrAlloc( p->nDivsMax );
+    p->vDivs2UN1 = Vec_PtrAlloc( p->nDivsMax );
+    p->vTemp     = Vec_PtrAlloc( p->nDivsMax );
+    return p;
+}
+
+/**Function*************************************************************
+
+  Synopsis    []
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Abc_ManResubStop( Abc_ManRes_t * p )
+{
+    Vec_PtrFree( p->vDivs );
+    Vec_PtrFree( p->vSims );
+    Vec_PtrFree( p->vDivs1UP );
+    Vec_PtrFree( p->vDivs1UN );
+    Vec_PtrFree( p->vDivs1B );
+    Vec_PtrFree( p->vDivs2UP0 );
+    Vec_PtrFree( p->vDivs2UP1 );
+    Vec_PtrFree( p->vDivs2UN0 );
+    Vec_PtrFree( p->vDivs2UN1 );
+    Vec_PtrFree( p->vTemp );
+    free( p->pInfo );
+    free( p );
+}
+
+/**Function*************************************************************
+
+  Synopsis    []
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Abc_ManResubPrint( Abc_ManRes_t * p )
+{
+    printf( "Used constants    = %6d.             ", p->nUsedNodeC );          PRT( "Cuts  ", p->timeCut );
+    printf( "Used replacements = %6d.             ", p->nUsedNode0 );          PRT( "Resub ", p->timeRes );
+    printf( "Used single ORs   = %6d.             ", p->nUsedNode1Or );        PRT( " Div  ", p->timeDiv );
+    printf( "Used single ANDs  = %6d.             ", p->nUsedNode1And );       PRT( " Mffc ", p->timeMffc );
+    printf( "Used double ORs   = %6d.             ", p->nUsedNode2Or );        PRT( " Sim  ", p->timeSim );
+    printf( "Used double ANDs  = %6d.             ", p->nUsedNode2And );       PRT( " 1    ", p->timeRes1 );
+    printf( "Used OR-AND       = %6d.             ", p->nUsedNode2OrAnd );     PRT( " D    ", p->timeResD );
+    printf( "Used AND-OR       = %6d.             ", p->nUsedNode2AndOr );     PRT( " 2    ", p->timeRes2 );
+    printf( "Used OR-2ANDs     = %6d.             ", p->nUsedNode3OrAnd );     PRT( "Truth ", p->timeTruth ); //PRT( " 3    ", p->timeRes3 );
+    printf( "Used AND-2ORs     = %6d.             ", p->nUsedNode3AndOr );     PRT( "AIG   ", p->timeNtk );
+    printf( "TOTAL             = %6d.             ", p->nUsedNodeC +
+                                                     p->nUsedNode0 +
+                                                     p->nUsedNode1Or +
+                                                     p->nUsedNode1And +
+                                                     p->nUsedNode2Or +
+                                                     p->nUsedNode2And +
+                                                     p->nUsedNode2OrAnd +
+                                                     p->nUsedNode2AndOr +
+                                                     p->nUsedNode3OrAnd +
+                                                     p->nUsedNode3AndOr
+                                                   );                          PRT( "TOTAL ", p->timeTotal );
+    printf( "Total leaves   = %8d.\n", p->nTotalLeaves );
+    printf( "Total divisors = %8d.\n", p->nTotalDivs );
+//    printf( "Total gain     = %8d.\n", p->nTotalGain );
+    printf( "Gain           = %8d. (%6.2f %%).\n", p->nNodesBeg-p->nNodesEnd, 100.0*(p->nNodesBeg-p->nNodesEnd)/p->nNodesBeg );
+}
+
+
+/**Function*************************************************************
+
+  Synopsis    []
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Abc_ManResubCollectDivs_rec( Abc_Obj_t * pNode, Vec_Ptr_t * vInternal )
+{
+    // skip visited nodes
+    if ( Abc_NodeIsTravIdCurrent(pNode) )
+        return;
+    Abc_NodeSetTravIdCurrent(pNode);
+    // collect the fanins
+    Abc_ManResubCollectDivs_rec( Abc_ObjFanin0(pNode), vInternal );
+    Abc_ManResubCollectDivs_rec( Abc_ObjFanin1(pNode), vInternal );
+    // collect the internal node
+    if ( pNode->fMarkA == 0 ) 
+        Vec_PtrPush( vInternal, pNode );
+}
+
+/**Function*************************************************************
+
+  Synopsis    []
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Abc_ManResubCollectDivs( Abc_ManRes_t * p, Abc_Obj_t * pRoot, Vec_Ptr_t * vLeaves, int Required )
+{
+    Abc_Obj_t * pNode, * pFanout;
+    int i, k, Limit, Counter;
+
+    Vec_PtrClear( p->vDivs1UP );
+    Vec_PtrClear( p->vDivs1UN );
+    Vec_PtrClear( p->vDivs1B );
+
+    // add the leaves of the cuts to the divisors
+    Vec_PtrClear( p->vDivs );
+    Abc_NtkIncrementTravId( pRoot->pNtk );
+    Vec_PtrForEachEntry( vLeaves, pNode, i )
+    {
+        Vec_PtrPush( p->vDivs, pNode );
+        Abc_NodeSetTravIdCurrent( pNode );        
+    }
+
+    // mark nodes in the MFFC
+    Vec_PtrForEachEntry( p->vTemp, pNode, i )
+        pNode->fMarkA = 1;
+    // collect the cone (without MFFC)
+    Abc_ManResubCollectDivs_rec( pRoot, p->vDivs );
+    // unmark the current MFFC
+    Vec_PtrForEachEntry( p->vTemp, pNode, i )
+        pNode->fMarkA = 0;
+
+    // check if the number of divisors is not exceeded
+    if ( Vec_PtrSize(p->vDivs) - Vec_PtrSize(vLeaves) + Vec_PtrSize(p->vTemp) >= Vec_PtrSize(p->vSims) - p->nLeavesMax )
+        return 0;
+
+    // get the number of divisors to collect
+    Limit = Vec_PtrSize(p->vSims) - p->nLeavesMax - (Vec_PtrSize(p->vDivs) - Vec_PtrSize(vLeaves) + Vec_PtrSize(p->vTemp));
+
+    // explore the fanouts, which are not in the MFFC
+    Counter = 0;
+    Vec_PtrForEachEntry( p->vDivs, pNode, i )
+    {
+        if ( Abc_ObjFanoutNum(pNode) > 100 )
+        {
+//            printf( "%d ", Abc_ObjFanoutNum(pNode) );
+            continue;
+        }
+        // if the fanout has both fanins in the set, add it
+        Abc_ObjForEachFanout( pNode, pFanout, k )
+        {
+            if ( Abc_NodeIsTravIdCurrent(pFanout) || Abc_ObjIsCo(pFanout) || (int)pFanout->Level > Required )
+                continue;
+            if ( Abc_NodeIsTravIdCurrent(Abc_ObjFanin0(pFanout)) && Abc_NodeIsTravIdCurrent(Abc_ObjFanin1(pFanout)) )
+            {
+                if ( Abc_ObjFanin0(pFanout) == pRoot || Abc_ObjFanin1(pFanout) == pRoot )
+                    continue;
+                Vec_PtrPush( p->vDivs, pFanout );
+                Abc_NodeSetTravIdCurrent( pFanout );
+                // quit computing divisors if there is too many of them
+                if ( ++Counter == Limit )
+                    goto Quits;
+            }
+        }
+    }
+
+Quits :
+    // get the number of divisors
+    p->nDivs = Vec_PtrSize(p->vDivs);
+
+    // add the nodes in the MFFC
+    Vec_PtrForEachEntry( p->vTemp, pNode, i )
+        Vec_PtrPush( p->vDivs, pNode );
+    assert( pRoot == Vec_PtrEntryLast(p->vDivs) );
+
+    assert( Vec_PtrSize(p->vDivs) - Vec_PtrSize(vLeaves) <= Vec_PtrSize(p->vSims) - p->nLeavesMax );
+    return 1;
+}
+
+/**Function*************************************************************
+
+  Synopsis    []
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Abc_ManResubPrintDivs( Abc_ManRes_t * p, Abc_Obj_t * pRoot, Vec_Ptr_t * vLeaves )
+{
+    Abc_Obj_t * pFanin, * pNode;
+    int i, k;
+    // print the nodes
+    Vec_PtrForEachEntry( p->vDivs, pNode, i )
+    {
+        if ( i < Vec_PtrSize(vLeaves) )
+        {
+            printf( "%6d : %c\n", pNode->Id, 'a'+i );
+            continue;
+        }
+        printf( "%6d : %2d = ", pNode->Id, i );
+        // find the first fanin
+        Vec_PtrForEachEntry( p->vDivs, pFanin, k )
+            if ( Abc_ObjFanin0(pNode) == pFanin )
+                break;
+        if ( k < Vec_PtrSize(vLeaves) )
+            printf( "%c", 'a' + k );
+        else
+            printf( "%d", k );
+        printf( "%s ", Abc_ObjFaninC0(pNode)? "\'" : "" );
+        // find the second fanin
+        Vec_PtrForEachEntry( p->vDivs, pFanin, k )
+            if ( Abc_ObjFanin1(pNode) == pFanin )
+                break;
+        if ( k < Vec_PtrSize(vLeaves) )
+            printf( "%c", 'a' + k );
+        else
+            printf( "%d", k );
+        printf( "%s ", Abc_ObjFaninC1(pNode)? "\'" : "" );
+        if ( pNode == pRoot )
+            printf( " root" );
+        printf( "\n" );
+    }
+    printf( "\n" );
+}
+
+
+/**Function*************************************************************
+
+  Synopsis    [Performs simulation.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Abc_ManResubSimulate( Vec_Ptr_t * vDivs, int nLeaves, Vec_Ptr_t * vSims, int nLeavesMax, int nWords )
+{
+    Abc_Obj_t * pObj;
+    unsigned * puData0, * puData1, * puData;
+    int i, k;
+    assert( Vec_PtrSize(vDivs) - nLeaves <= Vec_PtrSize(vSims) - nLeavesMax );
+    // simulate
+    Vec_PtrForEachEntry( vDivs, pObj, i )
+    {
+        if ( i < nLeaves )
+        { // initialize the leaf
+            pObj->pData = Vec_PtrEntry( vSims, i );
+            continue;
+        }
+        // set storage for the node's simulation info
+        pObj->pData = Vec_PtrEntry( vSims, i - nLeaves + nLeavesMax );
+        // get pointer to the simulation info
+        puData  = pObj->pData;
+        puData0 = Abc_ObjFanin0(pObj)->pData;
+        puData1 = Abc_ObjFanin1(pObj)->pData;
+        // simulate
+        if ( Abc_ObjFaninC0(pObj) && Abc_ObjFaninC1(pObj) )
+            for ( k = 0; k < nWords; k++ )
+                puData[k] = ~puData0[k] & ~puData1[k];
+        else if ( Abc_ObjFaninC0(pObj) )
+            for ( k = 0; k < nWords; k++ )
+                puData[k] = ~puData0[k] & puData1[k];
+        else if ( Abc_ObjFaninC1(pObj) )
+            for ( k = 0; k < nWords; k++ )
+                puData[k] = puData0[k] & ~puData1[k];
+        else 
+            for ( k = 0; k < nWords; k++ )
+                puData[k] = puData0[k] & puData1[k];
+    }
+    // normalize
+    Vec_PtrForEachEntry( vDivs, pObj, i )
+    {
+        puData = pObj->pData;
+        pObj->fPhase = (puData[0] & 1);
+        if ( pObj->fPhase )
+            for ( k = 0; k < nWords; k++ )
+                puData[k] = ~puData[k];
+    }
+}
+
+
+/**Function*************************************************************
+
+  Synopsis    []
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Dec_Graph_t * Abc_ManResubQuit0( Abc_Obj_t * pRoot, Abc_Obj_t * pObj )
+{
+    Dec_Graph_t * pGraph;
+    Dec_Edge_t eRoot;
+    pGraph = Dec_GraphCreate( 1 );
+    Dec_GraphNode( pGraph, 0 )->pFunc = pObj;
+    eRoot = Dec_EdgeCreate( 0, pObj->fPhase );
+    Dec_GraphSetRoot( pGraph, eRoot );
+    if ( pRoot->fPhase )
+        Dec_GraphComplement( pGraph );
+    return pGraph;
+}
+ 
+/**Function*************************************************************
+
+  Synopsis    []
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Dec_Graph_t * Abc_ManResubQuit1( Abc_Obj_t * pRoot, Abc_Obj_t * pObj0, Abc_Obj_t * pObj1, int fOrGate )
+{
+    Dec_Graph_t * pGraph;
+    Dec_Edge_t eRoot, eNode0, eNode1;
+    assert( pObj0 != pObj1 );
+    assert( !Abc_ObjIsComplement(pObj0) );
+    assert( !Abc_ObjIsComplement(pObj1) );
+    pGraph = Dec_GraphCreate( 2 );
+    Dec_GraphNode( pGraph, 0 )->pFunc = pObj0;
+    Dec_GraphNode( pGraph, 1 )->pFunc = pObj1;
+    eNode0 = Dec_EdgeCreate( 0, pObj0->fPhase );
+    eNode1 = Dec_EdgeCreate( 1, pObj1->fPhase );
+    if ( fOrGate ) 
+        eRoot  = Dec_GraphAddNodeOr( pGraph, eNode0, eNode1 );
+    else
+        eRoot  = Dec_GraphAddNodeAnd( pGraph, eNode0, eNode1 );
+    Dec_GraphSetRoot( pGraph, eRoot );
+    if ( pRoot->fPhase )
+        Dec_GraphComplement( pGraph );
+    return pGraph;
+}
+
+/**Function*************************************************************
+
+  Synopsis    []
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Dec_Graph_t * Abc_ManResubQuit21( Abc_Obj_t * pRoot, Abc_Obj_t * pObj0, Abc_Obj_t * pObj1, Abc_Obj_t * pObj2, int fOrGate )
+{
+    Dec_Graph_t * pGraph;
+    Dec_Edge_t eRoot, eNode0, eNode1, eNode2;
+    assert( pObj0 != pObj1 );
+    assert( !Abc_ObjIsComplement(pObj0) );
+    assert( !Abc_ObjIsComplement(pObj1) );
+    assert( !Abc_ObjIsComplement(pObj2) );
+    pGraph = Dec_GraphCreate( 3 );
+    Dec_GraphNode( pGraph, 0 )->pFunc = pObj0;
+    Dec_GraphNode( pGraph, 1 )->pFunc = pObj1;
+    Dec_GraphNode( pGraph, 2 )->pFunc = pObj2;
+    eNode0 = Dec_EdgeCreate( 0, pObj0->fPhase );
+    eNode1 = Dec_EdgeCreate( 1, pObj1->fPhase );
+    eNode2 = Dec_EdgeCreate( 2, pObj2->fPhase );
+    if ( fOrGate ) 
+    {
+        eRoot  = Dec_GraphAddNodeOr( pGraph, eNode0, eNode1 );
+        eRoot  = Dec_GraphAddNodeOr( pGraph, eNode2, eRoot );
+    }
+    else
+    {
+        eRoot  = Dec_GraphAddNodeAnd( pGraph, eNode0, eNode1 );
+        eRoot  = Dec_GraphAddNodeAnd( pGraph, eNode2, eRoot );
+    }
+    Dec_GraphSetRoot( pGraph, eRoot );
+    if ( pRoot->fPhase )
+        Dec_GraphComplement( pGraph );
+    return pGraph;
+}
+
+/**Function*************************************************************
+
+  Synopsis    []
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Dec_Graph_t * Abc_ManResubQuit2( Abc_Obj_t * pRoot, Abc_Obj_t * pObj0, Abc_Obj_t * pObj1, Abc_Obj_t * pObj2, int fOrGate )
+{
+    Dec_Graph_t * pGraph;
+    Dec_Edge_t eRoot, ePrev, eNode0, eNode1, eNode2;
+    assert( pObj0 != pObj1 );
+    assert( pObj0 != pObj2 );
+    assert( pObj1 != pObj2 );
+    assert( !Abc_ObjIsComplement(pObj0) );
+    pGraph = Dec_GraphCreate( 3 );
+    Dec_GraphNode( pGraph, 0 )->pFunc = Abc_ObjRegular(pObj0);
+    Dec_GraphNode( pGraph, 1 )->pFunc = Abc_ObjRegular(pObj1);
+    Dec_GraphNode( pGraph, 2 )->pFunc = Abc_ObjRegular(pObj2);
+    eNode0 = Dec_EdgeCreate( 0, Abc_ObjRegular(pObj0)->fPhase );
+    if ( Abc_ObjIsComplement(pObj1) && Abc_ObjIsComplement(pObj2) )
+    {
+        eNode1 = Dec_EdgeCreate( 1, Abc_ObjRegular(pObj1)->fPhase );
+        eNode2 = Dec_EdgeCreate( 2, Abc_ObjRegular(pObj2)->fPhase );
+        ePrev  = Dec_GraphAddNodeOr( pGraph, eNode1, eNode2 );
+    }
+    else
+    {
+        eNode1 = Dec_EdgeCreate( 1, Abc_ObjRegular(pObj1)->fPhase ^ Abc_ObjIsComplement(pObj1) );
+        eNode2 = Dec_EdgeCreate( 2, Abc_ObjRegular(pObj2)->fPhase ^ Abc_ObjIsComplement(pObj2) );
+        ePrev  = Dec_GraphAddNodeAnd( pGraph, eNode1, eNode2 );
+    }
+    if ( fOrGate ) 
+        eRoot  = Dec_GraphAddNodeOr( pGraph, eNode0, ePrev );
+    else
+        eRoot  = Dec_GraphAddNodeAnd( pGraph, eNode0, ePrev );
+    Dec_GraphSetRoot( pGraph, eRoot );
+    if ( pRoot->fPhase )
+        Dec_GraphComplement( pGraph );
+    return pGraph;
+}
+
+/**Function*************************************************************
+
+  Synopsis    []
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Dec_Graph_t * Abc_ManResubQuit3( Abc_Obj_t * pRoot, Abc_Obj_t * pObj0, Abc_Obj_t * pObj1, Abc_Obj_t * pObj2, Abc_Obj_t * pObj3, int fOrGate )
+{
+    Dec_Graph_t * pGraph;
+    Dec_Edge_t eRoot, ePrev0, ePrev1, eNode0, eNode1, eNode2, eNode3;
+    assert( pObj0 != pObj1 );
+    assert( pObj2 != pObj3 );
+    pGraph = Dec_GraphCreate( 4 );
+    Dec_GraphNode( pGraph, 0 )->pFunc = Abc_ObjRegular(pObj0);
+    Dec_GraphNode( pGraph, 1 )->pFunc = Abc_ObjRegular(pObj1);
+    Dec_GraphNode( pGraph, 2 )->pFunc = Abc_ObjRegular(pObj2);
+    Dec_GraphNode( pGraph, 3 )->pFunc = Abc_ObjRegular(pObj3);
+    if ( Abc_ObjIsComplement(pObj0) && Abc_ObjIsComplement(pObj1) )
+    {
+        eNode0 = Dec_EdgeCreate( 0, Abc_ObjRegular(pObj0)->fPhase );
+        eNode1 = Dec_EdgeCreate( 1, Abc_ObjRegular(pObj1)->fPhase );
+        ePrev0 = Dec_GraphAddNodeOr( pGraph, eNode0, eNode1 );
+        if ( Abc_ObjIsComplement(pObj2) && Abc_ObjIsComplement(pObj3) )
+        {
+            eNode2 = Dec_EdgeCreate( 2, Abc_ObjRegular(pObj2)->fPhase );
+            eNode3 = Dec_EdgeCreate( 3, Abc_ObjRegular(pObj3)->fPhase );
+            ePrev1 = Dec_GraphAddNodeOr( pGraph, eNode2, eNode3 );
+        }
+        else
+        {
+            eNode2 = Dec_EdgeCreate( 2, Abc_ObjRegular(pObj2)->fPhase ^ Abc_ObjIsComplement(pObj2) );
+            eNode3 = Dec_EdgeCreate( 3, Abc_ObjRegular(pObj3)->fPhase ^ Abc_ObjIsComplement(pObj3) );
+            ePrev1 = Dec_GraphAddNodeAnd( pGraph, eNode2, eNode3 );
+        }
+    }
+    else
+    {
+        eNode0 = Dec_EdgeCreate( 0, Abc_ObjRegular(pObj0)->fPhase ^ Abc_ObjIsComplement(pObj0) );
+        eNode1 = Dec_EdgeCreate( 1, Abc_ObjRegular(pObj1)->fPhase ^ Abc_ObjIsComplement(pObj1) );
+        ePrev0 = Dec_GraphAddNodeAnd( pGraph, eNode0, eNode1 );
+        if ( Abc_ObjIsComplement(pObj2) && Abc_ObjIsComplement(pObj3) )
+        {
+            eNode2 = Dec_EdgeCreate( 2, Abc_ObjRegular(pObj2)->fPhase );
+            eNode3 = Dec_EdgeCreate( 3, Abc_ObjRegular(pObj3)->fPhase );
+            ePrev1 = Dec_GraphAddNodeOr( pGraph, eNode2, eNode3 );
+        }
+        else
+        {
+            eNode2 = Dec_EdgeCreate( 2, Abc_ObjRegular(pObj2)->fPhase ^ Abc_ObjIsComplement(pObj2) );
+            eNode3 = Dec_EdgeCreate( 3, Abc_ObjRegular(pObj3)->fPhase ^ Abc_ObjIsComplement(pObj3) );
+            ePrev1 = Dec_GraphAddNodeAnd( pGraph, eNode2, eNode3 );
+        }
+    }
+    if ( fOrGate ) 
+        eRoot = Dec_GraphAddNodeOr( pGraph, ePrev0, ePrev1 );
+    else
+        eRoot = Dec_GraphAddNodeAnd( pGraph, ePrev0, ePrev1 );
+    Dec_GraphSetRoot( pGraph, eRoot );
+    if ( pRoot->fPhase )
+        Dec_GraphComplement( pGraph );
+    return pGraph;
+}
+
+
+
+
+/**Function*************************************************************
+
+  Synopsis    [Derives single-node unate/binate divisors.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Abc_ManResubDivsS( Abc_ManRes_t * p, int Required )
+{
+    Abc_Obj_t * pObj;
+    unsigned * puData, * puDataR;
+    int i, w;
+    Vec_PtrClear( p->vDivs1UP );
+    Vec_PtrClear( p->vDivs1UN );
+    Vec_PtrClear( p->vDivs1B );
+    puDataR = p->pRoot->pData;
+    Vec_PtrForEachEntryStop( p->vDivs, pObj, i, p->nDivs )
+    {
+        if ( (int)pObj->Level > Required - 1 )
+            continue;
+
+        puData = pObj->pData;
+        // check positive containment
+        for ( w = 0; w < p->nWords; w++ )
+//            if ( puData[w] & ~puDataR[w] )
+            if ( puData[w] & ~puDataR[w] & p->pCareSet[w] ) // care set
+                break;
+        if ( w == p->nWords )
+        {
+            Vec_PtrPush( p->vDivs1UP, pObj );
+            continue;
+        }
+        // check negative containment
+        for ( w = 0; w < p->nWords; w++ )
+//            if ( ~puData[w] & puDataR[w] )
+            if ( ~puData[w] & puDataR[w] & p->pCareSet[w] ) // care set
+                break;
+        if ( w == p->nWords )
+        {
+            Vec_PtrPush( p->vDivs1UN, pObj );
+            continue;
+        }
+        // add the node to binates
+        Vec_PtrPush( p->vDivs1B, pObj );
+    }
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Derives double-node unate/binate divisors.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Abc_ManResubDivsD( Abc_ManRes_t * p, int Required )
+{
+    Abc_Obj_t * pObj0, * pObj1;
+    unsigned * puData0, * puData1, * puDataR;
+    int i, k, w;
+    Vec_PtrClear( p->vDivs2UP0 );
+    Vec_PtrClear( p->vDivs2UP1 );
+    Vec_PtrClear( p->vDivs2UN0 );
+    Vec_PtrClear( p->vDivs2UN1 );
+    puDataR = p->pRoot->pData;
+    Vec_PtrForEachEntry( p->vDivs1B, pObj0, i )
+    {
+        if ( (int)pObj0->Level > Required - 2 )
+            continue;
+
+        puData0 = pObj0->pData;
+        Vec_PtrForEachEntryStart( p->vDivs1B, pObj1, k, i + 1 )
+        {
+            if ( (int)pObj1->Level > Required - 2 )
+                continue;
+
+            puData1 = pObj1->pData;
+
+            if ( Vec_PtrSize(p->vDivs2UP0) < ABC_RS_DIV2_MAX )
+            {
+                // get positive unate divisors
+                for ( w = 0; w < p->nWords; w++ )
+//                    if ( (puData0[w] & puData1[w]) & ~puDataR[w] )
+                    if ( (puData0[w] & puData1[w]) & ~puDataR[w] & p->pCareSet[w] ) // care set
+                        break;
+                if ( w == p->nWords )
+                {
+                    Vec_PtrPush( p->vDivs2UP0, pObj0 );
+                    Vec_PtrPush( p->vDivs2UP1, pObj1 );
+                }
+                for ( w = 0; w < p->nWords; w++ )
+//                    if ( (~puData0[w] & puData1[w]) & ~puDataR[w] )
+                    if ( (~puData0[w] & puData1[w]) & ~puDataR[w] & p->pCareSet[w] ) // care set
+                        break;
+                if ( w == p->nWords )
+                {
+                    Vec_PtrPush( p->vDivs2UP0, Abc_ObjNot(pObj0) );
+                    Vec_PtrPush( p->vDivs2UP1, pObj1 );
+                }
+                for ( w = 0; w < p->nWords; w++ )
+//                    if ( (puData0[w] & ~puData1[w]) & ~puDataR[w] )
+                    if ( (puData0[w] & ~puData1[w]) & ~puDataR[w] & p->pCareSet[w] ) // care set
+                        break;
+                if ( w == p->nWords )
+                {
+                    Vec_PtrPush( p->vDivs2UP0, pObj0 );
+                    Vec_PtrPush( p->vDivs2UP1, Abc_ObjNot(pObj1) );
+                }
+                for ( w = 0; w < p->nWords; w++ )
+//                    if ( (puData0[w] | puData1[w]) & ~puDataR[w] )
+                    if ( (puData0[w] | puData1[w]) & ~puDataR[w] & p->pCareSet[w] ) // care set
+                        break;
+                if ( w == p->nWords )
+                {
+                    Vec_PtrPush( p->vDivs2UP0, Abc_ObjNot(pObj0) );
+                    Vec_PtrPush( p->vDivs2UP1, Abc_ObjNot(pObj1) );
+                }
+            }
+
+            if ( Vec_PtrSize(p->vDivs2UN0) < ABC_RS_DIV2_MAX )
+            {
+                // get negative unate divisors
+                for ( w = 0; w < p->nWords; w++ )
+//                    if ( ~(puData0[w] & puData1[w]) & puDataR[w] )
+                    if ( ~(puData0[w] & puData1[w]) & puDataR[w] & p->pCareSet[w] ) // care set
+                        break;
+                if ( w == p->nWords )
+                {
+                    Vec_PtrPush( p->vDivs2UN0, pObj0 );
+                    Vec_PtrPush( p->vDivs2UN1, pObj1 );
+                }
+                for ( w = 0; w < p->nWords; w++ )
+//                    if ( ~(~puData0[w] & puData1[w]) & puDataR[w] )
+                    if ( ~(~puData0[w] & puData1[w]) & puDataR[w] & p->pCareSet[w] ) // care set
+                        break;
+                if ( w == p->nWords )
+                {
+                    Vec_PtrPush( p->vDivs2UN0, Abc_ObjNot(pObj0) );
+                    Vec_PtrPush( p->vDivs2UN1, pObj1 );
+                }
+                for ( w = 0; w < p->nWords; w++ )
+//                    if ( ~(puData0[w] & ~puData1[w]) & puDataR[w] )
+                    if ( ~(puData0[w] & ~puData1[w]) & puDataR[w] & p->pCareSet[w] ) // care set
+                        break;
+                if ( w == p->nWords )
+                {
+                    Vec_PtrPush( p->vDivs2UN0, pObj0 );
+                    Vec_PtrPush( p->vDivs2UN1, Abc_ObjNot(pObj1) );
+                }
+                for ( w = 0; w < p->nWords; w++ )
+//                    if ( ~(puData0[w] | puData1[w]) & puDataR[w] )
+                    if ( ~(puData0[w] | puData1[w]) & puDataR[w] & p->pCareSet[w] ) // care set
+                        break;
+                if ( w == p->nWords )
+                {
+                    Vec_PtrPush( p->vDivs2UN0, Abc_ObjNot(pObj0) );
+                    Vec_PtrPush( p->vDivs2UN1, Abc_ObjNot(pObj1) );
+                }
+            }
+        }
+    }
+//    printf( "%d %d  ", Vec_PtrSize(p->vDivs2UP0), Vec_PtrSize(p->vDivs2UN0) );
+}
+
+
+
+/**Function*************************************************************
+
+  Synopsis    []
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Dec_Graph_t * Abc_ManResubQuit( Abc_ManRes_t * p )
+{
+    Dec_Graph_t * pGraph;
+    unsigned * upData;
+    int w;
+    upData = p->pRoot->pData;
+    for ( w = 0; w < p->nWords; w++ )
+//        if ( upData[w] )
+        if ( upData[w] & p->pCareSet[w] ) // care set
+            break;
+    if ( w != p->nWords )
+        return NULL;
+    // get constant node graph
+    if ( p->pRoot->fPhase )
+        pGraph = Dec_GraphCreateConst1();
+    else 
+        pGraph = Dec_GraphCreateConst0();
+    return pGraph;
+}
+
+/**Function*************************************************************
+
+  Synopsis    []
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Dec_Graph_t * Abc_ManResubDivs0( Abc_ManRes_t * p )
+{
+    Abc_Obj_t * pObj;
+    unsigned * puData, * puDataR;
+    int i, w;
+    puDataR = p->pRoot->pData;
+    Vec_PtrForEachEntryStop( p->vDivs, pObj, i, p->nDivs )
+    {
+        puData = pObj->pData;
+        for ( w = 0; w < p->nWords; w++ )
+//            if ( puData[w] != puDataR[w] )
+            if ( (puData[w] ^ puDataR[w]) & p->pCareSet[w] ) // care set
+                break;
+        if ( w == p->nWords )
+            return Abc_ManResubQuit0( p->pRoot, pObj );
+    }
+    return NULL;
+}
+
+/**Function*************************************************************
+
+  Synopsis    []
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Dec_Graph_t * Abc_ManResubDivs1( Abc_ManRes_t * p, int Required )
+{
+    Abc_Obj_t * pObj0, * pObj1;
+    unsigned * puData0, * puData1, * puDataR;
+    int i, k, w;
+    puDataR = p->pRoot->pData;
+    // check positive unate divisors
+    Vec_PtrForEachEntry( p->vDivs1UP, pObj0, i )
+    {
+        puData0 = pObj0->pData;
+        Vec_PtrForEachEntryStart( p->vDivs1UP, pObj1, k, i + 1 )
+        {
+            puData1 = pObj1->pData;
+            for ( w = 0; w < p->nWords; w++ )
+//                if ( (puData0[w] | puData1[w]) != puDataR[w] )
+                if ( ((puData0[w] | puData1[w]) ^ puDataR[w]) & p->pCareSet[w] ) // care set
+                    break;
+            if ( w == p->nWords )
+            {
+                p->nUsedNode1Or++;
+                return Abc_ManResubQuit1( p->pRoot, pObj0, pObj1, 1 );
+            }
+        }
+    }
+    // check negative unate divisors
+    Vec_PtrForEachEntry( p->vDivs1UN, pObj0, i )
+    {
+        puData0 = pObj0->pData;
+        Vec_PtrForEachEntryStart( p->vDivs1UN, pObj1, k, i + 1 )
+        {
+            puData1 = pObj1->pData;
+            for ( w = 0; w < p->nWords; w++ )
+//                if ( (puData0[w] & puData1[w]) != puDataR[w] )
+                if ( ((puData0[w] & puData1[w]) ^ puDataR[w]) & p->pCareSet[w] ) // care set
+                    break;
+            if ( w == p->nWords )
+            {
+                p->nUsedNode1And++;
+                return Abc_ManResubQuit1( p->pRoot, pObj0, pObj1, 0 );
+            }
+        }
+    }
+    return NULL;
+}
+
+/**Function*************************************************************
+
+  Synopsis    []
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Dec_Graph_t * Abc_ManResubDivs12( Abc_ManRes_t * p, int Required )
+{
+    Abc_Obj_t * pObj0, * pObj1, * pObj2, * pObjMax, * pObjMin0, * pObjMin1;
+    unsigned * puData0, * puData1, * puData2, * puDataR;
+    int i, k, j, w, LevelMax;
+    puDataR = p->pRoot->pData;
+    // check positive unate divisors
+    Vec_PtrForEachEntry( p->vDivs1UP, pObj0, i )
+    {
+        puData0 = pObj0->pData;
+        Vec_PtrForEachEntryStart( p->vDivs1UP, pObj1, k, i + 1 )
+        {
+            puData1 = pObj1->pData;
+            Vec_PtrForEachEntryStart( p->vDivs1UP, pObj2, j, k + 1 )
+            {
+                puData2 = pObj2->pData;
+                for ( w = 0; w < p->nWords; w++ )
+//                    if ( (puData0[w] | puData1[w] | puData2[w]) != puDataR[w] )
+                    if ( ((puData0[w] | puData1[w] | puData2[w]) ^ puDataR[w]) & p->pCareSet[w] ) // care set
+                        break;
+                if ( w == p->nWords )
+                {
+                    LevelMax = ABC_MAX( pObj0->Level, ABC_MAX(pObj1->Level, pObj2->Level) );
+                    assert( LevelMax <= Required - 1 );
+
+                    pObjMax = NULL;
+                    if ( (int)pObj0->Level == LevelMax )
+                        pObjMax = pObj0, pObjMin0 = pObj1, pObjMin1 = pObj2;
+                    if ( (int)pObj1->Level == LevelMax )
+                    {
+                        if ( pObjMax ) continue;
+                        pObjMax = pObj1, pObjMin0 = pObj0, pObjMin1 = pObj2;
+                    }
+                    if ( (int)pObj2->Level == LevelMax )
+                    {
+                        if ( pObjMax ) continue;
+                        pObjMax = pObj2, pObjMin0 = pObj0, pObjMin1 = pObj1;
+                    }
+
+                    p->nUsedNode2Or++;
+                    return Abc_ManResubQuit21( p->pRoot, pObjMin0, pObjMin1, pObjMax, 1 );
+                }
+            }
+        }
+    }
+    // check negative unate divisors
+    Vec_PtrForEachEntry( p->vDivs1UN, pObj0, i )
+    {
+        puData0 = pObj0->pData;
+        Vec_PtrForEachEntryStart( p->vDivs1UN, pObj1, k, i + 1 )
+        {
+            puData1 = pObj1->pData;
+            Vec_PtrForEachEntryStart( p->vDivs1UN, pObj2, j, k + 1 )
+            {
+                puData2 = pObj2->pData;
+                for ( w = 0; w < p->nWords; w++ )
+//                    if ( (puData0[w] & puData1[w] & puData2[w]) != puDataR[w] )
+                    if ( ((puData0[w] & puData1[w] & puData2[w]) ^ puDataR[w]) & p->pCareSet[w] ) // care set
+                        break;
+                if ( w == p->nWords )
+                {
+                    LevelMax = ABC_MAX( pObj0->Level, ABC_MAX(pObj1->Level, pObj2->Level) );
+                    assert( LevelMax <= Required - 1 );
+
+                    pObjMax = NULL;
+                    if ( (int)pObj0->Level == LevelMax )
+                        pObjMax = pObj0, pObjMin0 = pObj1, pObjMin1 = pObj2;
+                    if ( (int)pObj1->Level == LevelMax )
+                    {
+                        if ( pObjMax ) continue;
+                        pObjMax = pObj1, pObjMin0 = pObj0, pObjMin1 = pObj2;
+                    }
+                    if ( (int)pObj2->Level == LevelMax )
+                    {
+                        if ( pObjMax ) continue;
+                        pObjMax = pObj2, pObjMin0 = pObj0, pObjMin1 = pObj1;
+                    }
+
+                    p->nUsedNode2And++;
+                    return Abc_ManResubQuit21( p->pRoot, pObjMin0, pObjMin1, pObjMax, 0 );
+                }
+            }
+        }
+    }
+    return NULL;
+}
+
+/**Function*************************************************************
+
+  Synopsis    []
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Dec_Graph_t * Abc_ManResubDivs2( Abc_ManRes_t * p, int Required )
+{
+    Abc_Obj_t * pObj0, * pObj1, * pObj2;
+    unsigned * puData0, * puData1, * puData2, * puDataR;
+    int i, k, w;
+    puDataR = p->pRoot->pData;
+    // check positive unate divisors
+    Vec_PtrForEachEntry( p->vDivs1UP, pObj0, i )
+    {
+        puData0 = pObj0->pData;
+        Vec_PtrForEachEntry( p->vDivs2UP0, pObj1, k )
+        {
+            pObj2 = Vec_PtrEntry( p->vDivs2UP1, k );
+
+            puData1 = Abc_ObjRegular(pObj1)->pData;
+            puData2 = Abc_ObjRegular(pObj2)->pData;
+            if ( Abc_ObjIsComplement(pObj1) && Abc_ObjIsComplement(pObj2) )
+            {
+                for ( w = 0; w < p->nWords; w++ )
+//                    if ( (puData0[w] | (puData1[w] | puData2[w])) != puDataR[w] )
+                    if ( ((puData0[w] | (puData1[w] | puData2[w])) ^ puDataR[w]) & p->pCareSet[w] ) // care set
+                        break;
+            }
+            else if ( Abc_ObjIsComplement(pObj1) )
+            {
+                for ( w = 0; w < p->nWords; w++ )
+//                    if ( (puData0[w] | (~puData1[w] & puData2[w])) != puDataR[w] )
+                    if ( ((puData0[w] | (~puData1[w] & puData2[w])) ^ puDataR[w]) & p->pCareSet[w] ) // care set
+                        break;
+            }
+            else if ( Abc_ObjIsComplement(pObj2) )
+            {
+                for ( w = 0; w < p->nWords; w++ )
+//                    if ( (puData0[w] | (puData1[w] & ~puData2[w])) != puDataR[w] )
+                    if ( ((puData0[w] | (puData1[w] & ~puData2[w])) ^ puDataR[w]) & p->pCareSet[w] ) // care set
+                        break;
+            }
+            else 
+            {
+                for ( w = 0; w < p->nWords; w++ )
+//                    if ( (puData0[w] | (puData1[w] & puData2[w])) != puDataR[w] )
+                    if ( ((puData0[w] | (puData1[w] & puData2[w])) ^ puDataR[w]) & p->pCareSet[w] ) // care set
+                        break;
+            }
+            if ( w == p->nWords )
+            {
+                p->nUsedNode2OrAnd++;
+                return Abc_ManResubQuit2( p->pRoot, pObj0, pObj1, pObj2, 1 );
+            }
+        }
+    }
+    // check negative unate divisors
+    Vec_PtrForEachEntry( p->vDivs1UN, pObj0, i )
+    {
+        puData0 = pObj0->pData;
+        Vec_PtrForEachEntry( p->vDivs2UN0, pObj1, k )
+        {
+            pObj2 = Vec_PtrEntry( p->vDivs2UN1, k );
+
+            puData1 = Abc_ObjRegular(pObj1)->pData;
+            puData2 = Abc_ObjRegular(pObj2)->pData;
+            if ( Abc_ObjIsComplement(pObj1) && Abc_ObjIsComplement(pObj2) )
+            {
+                for ( w = 0; w < p->nWords; w++ )
+//                    if ( (puData0[w] & (puData1[w] | puData2[w])) != puDataR[w] )
+                    if ( ((puData0[w] & (puData1[w] | puData2[w])) ^ puDataR[w]) & p->pCareSet[w] ) // care set
+                        break;
+            }
+            else if ( Abc_ObjIsComplement(pObj1) )
+            {
+                for ( w = 0; w < p->nWords; w++ )
+//                    if ( (puData0[w] & (~puData1[w] & puData2[w])) != puDataR[w] )
+                    if ( ((puData0[w] & (~puData1[w] & puData2[w])) ^ puDataR[w]) & p->pCareSet[w] ) // care set
+                        break;
+            }
+            else if ( Abc_ObjIsComplement(pObj2) )
+            {
+                for ( w = 0; w < p->nWords; w++ )
+//                    if ( (puData0[w] & (puData1[w] & ~puData2[w])) != puDataR[w] )
+                    if ( ((puData0[w] & (puData1[w] & ~puData2[w])) ^ puDataR[w]) & p->pCareSet[w] ) // care set
+                        break;
+            }
+            else 
+            {
+                for ( w = 0; w < p->nWords; w++ )
+//                    if ( (puData0[w] & (puData1[w] & puData2[w])) != puDataR[w] )
+                    if ( ((puData0[w] & (puData1[w] & puData2[w])) ^ puDataR[w]) & p->pCareSet[w] ) // care set
+                        break;
+            }
+            if ( w == p->nWords )
+            {
+                p->nUsedNode2AndOr++;
+                return Abc_ManResubQuit2( p->pRoot, pObj0, pObj1, pObj2, 0 );
+            }
+        }
+    }
+    return NULL;
+}
+
+/**Function*************************************************************
+
+  Synopsis    []
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Dec_Graph_t * Abc_ManResubDivs3( Abc_ManRes_t * p, int Required )
+{
+    Abc_Obj_t * pObj0, * pObj1, * pObj2, * pObj3;
+    unsigned * puData0, * puData1, * puData2, * puData3, * puDataR;
+    int i, k, w, Flag;
+    puDataR = p->pRoot->pData;
+    // check positive unate divisors
+    Vec_PtrForEachEntry( p->vDivs2UP0, pObj0, i )
+    {
+        pObj1 = Vec_PtrEntry( p->vDivs2UP1, i );
+        puData0 = Abc_ObjRegular(pObj0)->pData;
+        puData1 = Abc_ObjRegular(pObj1)->pData;
+        Flag = (Abc_ObjIsComplement(pObj0) << 3) | (Abc_ObjIsComplement(pObj1) << 2);
+
+        Vec_PtrForEachEntryStart( p->vDivs2UP0, pObj2, k, i + 1 )
+        {
+            pObj3 = Vec_PtrEntry( p->vDivs2UP1, k );
+            puData2 = Abc_ObjRegular(pObj2)->pData;
+            puData3 = Abc_ObjRegular(pObj3)->pData;
+
+            Flag = (Flag & 12) | (Abc_ObjIsComplement(pObj2) << 1) | Abc_ObjIsComplement(pObj3);
+            assert( Flag < 16 );
+            switch( Flag )
+            {
+            case 0: // 0000
+                for ( w = 0; w < p->nWords; w++ )
+//                    if ( ((puData0[w] & puData1[w]) | (puData2[w] & puData3[w])) != puDataR[w] )
+                    if ( (((puData0[w] & puData1[w]) | (puData2[w] & puData3[w])) ^ puDataR[w]) & p->pCareSet[w] ) // care set
+                        break;
+                break;
+            case 1: // 0001
+                for ( w = 0; w < p->nWords; w++ )
+//                    if ( ((puData0[w] & puData1[w]) | (puData2[w] & ~puData3[w])) != puDataR[w] )
+                    if ( (((puData0[w] & puData1[w]) | (puData2[w] & ~puData3[w])) ^ puDataR[w]) & p->pCareSet[w] ) // care set
+                        break;
+                break;
+            case 2: // 0010
+                for ( w = 0; w < p->nWords; w++ )
+//                    if ( ((puData0[w] & puData1[w]) | (~puData2[w] & puData3[w])) != puDataR[w] )
+                    if ( (((puData0[w] & puData1[w]) | (~puData2[w] & puData3[w])) ^ puDataR[w]) & p->pCareSet[w] ) // care set
+                        break;
+                break;
+            case 3: // 0011
+                for ( w = 0; w < p->nWords; w++ )
+//                    if ( ((puData0[w] & puData1[w]) | (puData2[w] | puData3[w])) != puDataR[w] )
+                    if ( (((puData0[w] & puData1[w]) | (puData2[w] | puData3[w])) ^ puDataR[w]) & p->pCareSet[w] ) // care set
+                        break;
+                break;
+
+            case 4: // 0100
+                for ( w = 0; w < p->nWords; w++ )
+//                    if ( ((puData0[w] & ~puData1[w]) | (puData2[w] & puData3[w])) != puDataR[w] )
+                    if ( (((puData0[w] & ~puData1[w]) | (puData2[w] & puData3[w])) ^ puDataR[w]) & p->pCareSet[w] ) // care set
+                        break;
+                break;
+            case 5: // 0101
+                for ( w = 0; w < p->nWords; w++ )
+//                    if ( ((puData0[w] & ~puData1[w]) | (puData2[w] & ~puData3[w])) != puDataR[w] )
+                    if ( (((puData0[w] & ~puData1[w]) | (puData2[w] & ~puData3[w])) ^ puDataR[w]) & p->pCareSet[w] ) // care set
+                        break;
+                break;
+            case 6: // 0110
+                for ( w = 0; w < p->nWords; w++ )
+//                    if ( ((puData0[w] & ~puData1[w]) | (~puData2[w] & puData3[w])) != puDataR[w] )
+                    if ( (((puData0[w] & ~puData1[w]) | (~puData2[w] & puData3[w])) ^ puDataR[w]) & p->pCareSet[w] ) // care set
+                        break;
+                break;
+            case 7: // 0111
+                for ( w = 0; w < p->nWords; w++ )
+//                    if ( ((puData0[w] & ~puData1[w]) | (puData2[w] | puData3[w])) != puDataR[w] )
+                    if ( (((puData0[w] & ~puData1[w]) | (puData2[w] | puData3[w])) ^ puDataR[w]) & p->pCareSet[w] ) // care set
+                        break;
+                break;
+
+            case 8: // 1000
+                for ( w = 0; w < p->nWords; w++ )
+//                    if ( ((~puData0[w] & puData1[w]) | (puData2[w] & puData3[w])) != puDataR[w] )
+                    if ( (((~puData0[w] & puData1[w]) | (puData2[w] & puData3[w])) ^ puDataR[w]) & p->pCareSet[w] ) // care set
+                        break;
+                break;
+            case 9: // 1001
+                for ( w = 0; w < p->nWords; w++ )
+//                    if ( ((~puData0[w] & puData1[w]) | (puData2[w] & ~puData3[w])) != puDataR[w] )
+                    if ( (((~puData0[w] & puData1[w]) | (puData2[w] & ~puData3[w])) ^ puDataR[w]) & p->pCareSet[w] ) // care set
+                        break;
+                break;
+            case 10: // 1010
+                for ( w = 0; w < p->nWords; w++ )
+//                    if ( ((~puData0[w] & puData1[w]) | (~puData2[w] & puData3[w])) != puDataR[w] )
+                    if ( (((~puData0[w] & puData1[w]) | (~puData2[w] & puData3[w])) ^ puDataR[w]) & p->pCareSet[w] ) // care set
+                        break;
+                break;
+            case 11: // 1011
+                for ( w = 0; w < p->nWords; w++ )
+//                    if ( ((~puData0[w] & puData1[w]) | (puData2[w] | puData3[w])) != puDataR[w] )
+                    if ( (((~puData0[w] & puData1[w]) | (puData2[w] | puData3[w])) ^ puDataR[w]) & p->pCareSet[w] ) // care set
+                        break;
+                break;
+
+            case 12: // 1100
+                for ( w = 0; w < p->nWords; w++ )
+//                    if ( ((puData0[w] | puData1[w]) | (puData2[w] & puData3[w])) != puDataR[w] )
+                    if ( (((puData0[w] | puData1[w]) | (puData2[w] & puData3[w])) ^ puDataR[w]) & p->pCareSet[w] ) // care set
+                        break;
+                break;
+            case 13: // 1101
+                for ( w = 0; w < p->nWords; w++ )
+//                    if ( ((puData0[w] | puData1[w]) | (puData2[w] & ~puData3[w])) != puDataR[w] )
+                    if ( (((puData0[w] | puData1[w]) | (puData2[w] & ~puData3[w])) ^ puDataR[w]) & p->pCareSet[w] )
+                        break;
+                break;
+            case 14: // 1110
+                for ( w = 0; w < p->nWords; w++ )
+//                    if ( ((puData0[w] | puData1[w]) | (~puData2[w] & puData3[w])) != puDataR[w] )
+                    if ( (((puData0[w] | puData1[w]) | (~puData2[w] & puData3[w])) ^ puDataR[w]) & p->pCareSet[w] )
+                        break;
+                break;
+            case 15: // 1111
+                for ( w = 0; w < p->nWords; w++ )
+//                    if ( ((puData0[w] | puData1[w]) | (puData2[w] | puData3[w])) != puDataR[w] )
+                    if ( (((puData0[w] | puData1[w]) | (puData2[w] | puData3[w])) ^ puDataR[w]) & p->pCareSet[w] )
+                        break;
+                break;
+
+            }
+            if ( w == p->nWords )
+            {
+                p->nUsedNode3OrAnd++;
+                return Abc_ManResubQuit3( p->pRoot, pObj0, pObj1, pObj2, pObj3, 1 );
+            }
+        }
+    }
+/*
+    // check negative unate divisors
+    Vec_PtrForEachEntry( p->vDivs2UN0, pObj0, i )
+    {
+        pObj1 = Vec_PtrEntry( p->vDivs2UN1, i );
+        puData0 = Abc_ObjRegular(pObj0)->pData;
+        puData1 = Abc_ObjRegular(pObj1)->pData;
+        Flag = (Abc_ObjIsComplement(pObj0) << 3) | (Abc_ObjIsComplement(pObj1) << 2);
+
+        Vec_PtrForEachEntryStart( p->vDivs2UN0, pObj2, k, i + 1 )
+        {
+            pObj3 = Vec_PtrEntry( p->vDivs2UN1, k );
+            puData2 = Abc_ObjRegular(pObj2)->pData;
+            puData3 = Abc_ObjRegular(pObj3)->pData;
+
+            Flag = (Flag & 12) | (Abc_ObjIsComplement(pObj2) << 1) | Abc_ObjIsComplement(pObj3);
+            assert( Flag < 16 );
+            switch( Flag )
+            {
+            case 0: // 0000
+                for ( w = 0; w < p->nWords; w++ )
+                    if ( ((puData0[w] & puData1[w]) & (puData2[w] & puData3[w])) != puDataR[w] )
+                        break;
+                break;
+            case 1: // 0001
+                for ( w = 0; w < p->nWords; w++ )
+                    if ( ((puData0[w] & puData1[w]) & (puData2[w] & ~puData3[w])) != puDataR[w] )
+                        break;
+                break;
+            case 2: // 0010
+                for ( w = 0; w < p->nWords; w++ )
+                    if ( ((puData0[w] & puData1[w]) & (~puData2[w] & puData3[w])) != puDataR[w] )
+                        break;
+                break;
+            case 3: // 0011
+                for ( w = 0; w < p->nWords; w++ )
+                    if ( ((puData0[w] & puData1[w]) & (puData2[w] | puData3[w])) != puDataR[w] )
+                        break;
+                break;
+
+            case 4: // 0100
+                for ( w = 0; w < p->nWords; w++ )
+                    if ( ((puData0[w] & ~puData1[w]) & (puData2[w] & puData3[w])) != puDataR[w] )
+                        break;
+                break;
+            case 5: // 0101
+                for ( w = 0; w < p->nWords; w++ )
+                    if ( ((puData0[w] & ~puData1[w]) & (puData2[w] & ~puData3[w])) != puDataR[w] )
+                        break;
+                break;
+            case 6: // 0110
+                for ( w = 0; w < p->nWords; w++ )
+                    if ( ((puData0[w] & ~puData1[w]) & (~puData2[w] & puData3[w])) != puDataR[w] )
+                        break;
+                break;
+            case 7: // 0111
+                for ( w = 0; w < p->nWords; w++ )
+                    if ( ((puData0[w] & ~puData1[w]) & (puData2[w] | puData3[w])) != puDataR[w] )
+                        break;
+                break;
+
+            case 8: // 1000
+                for ( w = 0; w < p->nWords; w++ )
+                    if ( ((~puData0[w] & puData1[w]) & (puData2[w] & puData3[w])) != puDataR[w] )
+                        break;
+                break;
+            case 9: // 1001
+                for ( w = 0; w < p->nWords; w++ )
+                    if ( ((~puData0[w] & puData1[w]) & (puData2[w] & ~puData3[w])) != puDataR[w] )
+                        break;
+                break;
+            case 10: // 1010
+                for ( w = 0; w < p->nWords; w++ )
+                    if ( ((~puData0[w] & puData1[w]) & (~puData2[w] & puData3[w])) != puDataR[w] )
+                        break;
+                break;
+            case 11: // 1011
+                for ( w = 0; w < p->nWords; w++ )
+                    if ( ((~puData0[w] & puData1[w]) & (puData2[w] | puData3[w])) != puDataR[w] )
+                        break;
+                break;
+
+            case 12: // 1100
+                for ( w = 0; w < p->nWords; w++ )
+                    if ( ((puData0[w] | puData1[w]) & (puData2[w] & puData3[w])) != puDataR[w] )
+                        break;
+                break;
+            case 13: // 1101
+                for ( w = 0; w < p->nWords; w++ )
+                    if ( ((puData0[w] | puData1[w]) & (puData2[w] & ~puData3[w])) != puDataR[w] )
+                        break;
+                break;
+            case 14: // 1110
+                for ( w = 0; w < p->nWords; w++ )
+                    if ( ((puData0[w] | puData1[w]) & (~puData2[w] & puData3[w])) != puDataR[w] )
+                        break;
+                break;
+            case 15: // 1111
+                for ( w = 0; w < p->nWords; w++ )
+                    if ( ((puData0[w] | puData1[w]) & (puData2[w] | puData3[w])) != puDataR[w] )
+                        break;
+                break;
+
+            }
+            if ( w == p->nWords )
+            {
+                p->nUsedNode3AndOr++;
+                return Abc_ManResubQuit3( p->pRoot, pObj0, pObj1, pObj2, pObj3, 0 );
+            }
+        }
+    }
+*/
+    return NULL;
+}
+
+/**Function*************************************************************
+
+  Synopsis    []
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Abc_ManResubCleanup( Abc_ManRes_t * p )
+{
+    Abc_Obj_t * pObj;
+    int i;
+    Vec_PtrForEachEntry( p->vDivs, pObj, i )
+        pObj->pData = NULL;
+    Vec_PtrClear( p->vDivs );
+    p->pRoot = NULL;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Evaluates resubstution of one cut.]
+
+  Description [Returns the graph to add if any.]
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Dec_Graph_t * Abc_ManResubEval( Abc_ManRes_t * p, Abc_Obj_t * pRoot, Vec_Ptr_t * vLeaves, int nSteps, bool fUpdateLevel, bool fVerbose )
+{
+    extern int Abc_NodeMffsInside( Abc_Obj_t * pNode, Vec_Ptr_t * vLeaves, Vec_Ptr_t * vInside );
+    Dec_Graph_t * pGraph;
+    int Required;
+    int clk;
+
+    Required = fUpdateLevel? Abc_ObjRequiredLevel(pRoot) : ABC_INFINITY;
+
+    assert( nSteps >= 0 );
+    assert( nSteps <= 3 );
+    p->pRoot = pRoot;
+    p->nLeaves = Vec_PtrSize(vLeaves);
+    p->nLastGain = -1;
+
+    // collect the MFFC
+clk = clock();
+    p->nMffc = Abc_NodeMffsInside( pRoot, vLeaves, p->vTemp );
+p->timeMffc += clock() - clk;
+    assert( p->nMffc > 0 );
+
+    // collect the divisor nodes
+clk = clock();
+    if ( !Abc_ManResubCollectDivs( p, pRoot, vLeaves, Required ) )
+        return NULL;
+    p->timeDiv += clock() - clk;
+
+    p->nTotalDivs   += p->nDivs;
+    p->nTotalLeaves += p->nLeaves;
+
+    // simulate the nodes
+clk = clock();
+    Abc_ManResubSimulate( p->vDivs, p->nLeaves, p->vSims, p->nLeavesMax, p->nWords );
+p->timeSim += clock() - clk;
+
+clk = clock();
+    // consider constants
+    if ( pGraph = Abc_ManResubQuit( p ) )
+    {
+        p->nUsedNodeC++;
+        p->nLastGain = p->nMffc;
+        return pGraph;
+    }
+
+    // consider equal nodes
+    if ( pGraph = Abc_ManResubDivs0( p ) )
+    {
+p->timeRes1 += clock() - clk;
+        p->nUsedNode0++;
+        p->nLastGain = p->nMffc;
+        return pGraph;
+    }
+    if ( nSteps == 0 || p->nMffc == 1 )
+    {
+p->timeRes1 += clock() - clk;
+        return NULL;
+    }
+
+    // get the one level divisors
+    Abc_ManResubDivsS( p, Required );
+
+    // consider one node
+    if ( pGraph = Abc_ManResubDivs1( p, Required ) )
+    {
+p->timeRes1 += clock() - clk;
+        p->nLastGain = p->nMffc - 1;
+        return pGraph;
+    }
+p->timeRes1 += clock() - clk;
+    if ( nSteps == 1 || p->nMffc == 2 )
+        return NULL;
+
+clk = clock();
+    // consider triples
+    if ( pGraph = Abc_ManResubDivs12( p, Required ) )
+    {
+p->timeRes2 += clock() - clk;
+        p->nLastGain = p->nMffc - 2;
+        return pGraph;
+    }
+p->timeRes2 += clock() - clk;
+
+    // get the two level divisors
+clk = clock();
+    Abc_ManResubDivsD( p, Required );
+p->timeResD += clock() - clk;
+
+    // consider two nodes
+clk = clock();
+    if ( pGraph = Abc_ManResubDivs2( p, Required ) )
+    {
+p->timeRes2 += clock() - clk;
+        p->nLastGain = p->nMffc - 2;
+        return pGraph;
+    }
+p->timeRes2 += clock() - clk;
+    if ( nSteps == 2 || p->nMffc == 3 )
+        return NULL;
+
+    // consider two nodes
+clk = clock();
+    if ( pGraph = Abc_ManResubDivs3( p, Required ) )
+    {
+p->timeRes3 += clock() - clk;
+        p->nLastGain = p->nMffc - 3;
+        return pGraph;
+    }
+p->timeRes3 += clock() - clk;
+    if ( nSteps == 3 || p->nLeavesMax == 4 )
+        return NULL;
+    return NULL;
+}
+
+
+
+
+/**Function*************************************************************
+
+  Synopsis    [Computes the volume and checks if the cut is feasible.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Abc_CutVolumeCheck_rec( Abc_Obj_t * pObj )
+{
+    // quit if the node is visited (or if it is a leaf)
+    if ( Abc_NodeIsTravIdCurrent(pObj) )
+        return 0;
+    Abc_NodeSetTravIdCurrent(pObj);
+    // report the error
+    if ( Abc_ObjIsCi(pObj) )
+        printf( "Abc_CutVolumeCheck() ERROR: The set of nodes is not a cut!\n" );
+    // count the number of nodes in the leaves
+    return 1 + Abc_CutVolumeCheck_rec( Abc_ObjFanin0(pObj) ) +
+        Abc_CutVolumeCheck_rec( Abc_ObjFanin1(pObj) );
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Computes the volume and checks if the cut is feasible.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Abc_CutVolumeCheck( Abc_Obj_t * pNode, Vec_Ptr_t * vLeaves )
+{
+    Abc_Obj_t * pObj;
+    int i;
+    // mark the leaves
+    Abc_NtkIncrementTravId( pNode->pNtk );
+    Vec_PtrForEachEntry( vLeaves, pObj, i )
+        Abc_NodeSetTravIdCurrent( pObj ); 
+    // traverse the nodes starting from the given one and count them
+    return Abc_CutVolumeCheck_rec( pNode );
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Computes the factor cut of the node.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Abc_CutFactor_rec( Abc_Obj_t * pObj, Vec_Ptr_t * vLeaves )
+{
+    if ( pObj->fMarkA )
+        return;
+    if ( Abc_ObjIsCi(pObj) || (Abc_ObjFanoutNum(pObj) > 1 && !Abc_NodeIsMuxControlType(pObj)) )
+    {
+        Vec_PtrPush( vLeaves, pObj );
+        pObj->fMarkA = 1;
+        return;
+    }
+    Abc_CutFactor_rec( Abc_ObjFanin0(pObj), vLeaves );
+    Abc_CutFactor_rec( Abc_ObjFanin1(pObj), vLeaves );
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Computes the factor cut of the node.]
+
+  Description [Factor-cut is the cut at a node in terms of factor-nodes.
+  Factor-nodes are roots of the node trees (MUXes/EXORs are counted as single nodes).
+  Factor-cut is unique for the given node.]
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Vec_Ptr_t * Abc_CutFactor( Abc_Obj_t * pNode )
+{
+    Vec_Ptr_t * vLeaves;
+    Abc_Obj_t * pObj;
+    int i;
+    assert( !Abc_ObjIsCi(pNode) );
+    vLeaves  = Vec_PtrAlloc( 10 );
+    Abc_CutFactor_rec( Abc_ObjFanin0(pNode), vLeaves );
+    Abc_CutFactor_rec( Abc_ObjFanin1(pNode), vLeaves );
+    Vec_PtrForEachEntry( vLeaves, pObj, i )
+        pObj->fMarkA = 0;
+    return vLeaves;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Cut computation.]
+
+  Description [This cut computation works as follows: 
+  It starts with the factor cut at the node. If the factor-cut is large, quit.
+  It supports the set of leaves of the cut under construction and labels all nodes
+  in the cut under construction, including the leaves.
+  It computes the factor-cuts of the leaves and checks if it is easible to add any of them.
+  If it is, it randomly chooses one feasible and continues.]
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Vec_Ptr_t * Abc_CutFactorLarge( Abc_Obj_t * pNode, int nLeavesMax )
+{
+    Vec_Ptr_t * vLeaves, * vFactors, * vFact, * vNext;
+    Vec_Int_t * vFeasible;
+    Abc_Obj_t * pLeaf, * pTemp;
+    int i, k, Counter, RandLeaf;
+    int BestCut, BestShare;
+    assert( Abc_ObjIsNode(pNode) );
+    // get one factor-cut
+    vLeaves = Abc_CutFactor( pNode );
+    if ( Vec_PtrSize(vLeaves) > nLeavesMax )
+    {
+        Vec_PtrFree(vLeaves);
+        return NULL;
+    }
+    if ( Vec_PtrSize(vLeaves) == nLeavesMax )
+        return vLeaves;
+    // initialize the factor cuts for the leaves
+    vFactors = Vec_PtrAlloc( nLeavesMax );
+    Abc_NtkIncrementTravId( pNode->pNtk );
+    Vec_PtrForEachEntry( vLeaves, pLeaf, i )
+    {
+        Abc_NodeSetTravIdCurrent( pLeaf ); 
+        if ( Abc_ObjIsCi(pLeaf) )
+            Vec_PtrPush( vFactors, NULL );
+        else
+            Vec_PtrPush( vFactors, Abc_CutFactor(pLeaf) );
+    }
+    // construct larger factor cuts
+    vFeasible = Vec_IntAlloc( nLeavesMax );
+    while ( 1 )
+    {
+        BestCut = -1;
+        // find the next feasible cut to add
+        Vec_IntClear( vFeasible );
+        Vec_PtrForEachEntry( vFactors, vFact, i )
+        {
+            if ( vFact == NULL )
+                continue;
+            // count the number of unmarked leaves of this factor cut
+            Counter = 0;
+            Vec_PtrForEachEntry( vFact, pTemp, k )
+                Counter += !Abc_NodeIsTravIdCurrent(pTemp);
+            // if the number of new leaves is smaller than the diff, it is feasible
+            if ( Counter <= nLeavesMax - Vec_PtrSize(vLeaves) + 1 )
+            {
+                Vec_IntPush( vFeasible, i );
+                if ( BestCut == -1 || BestShare < Vec_PtrSize(vFact) - Counter )
+                    BestCut = i, BestShare = Vec_PtrSize(vFact) - Counter;
+            }
+        }
+        // quit if there is no feasible factor cuts
+        if ( Vec_IntSize(vFeasible) == 0 )
+            break;
+        // randomly choose one leaf and get its factor cut
+//        RandLeaf = Vec_IntEntry( vFeasible, rand() % Vec_IntSize(vFeasible) );
+        // choose the cut that has most sharing with the other cuts
+        RandLeaf = BestCut;
+
+        pLeaf = Vec_PtrEntry( vLeaves, RandLeaf );
+        vNext = Vec_PtrEntry( vFactors, RandLeaf );
+        // unmark this leaf
+        Abc_NodeSetTravIdPrevious( pLeaf ); 
+        // remove this cut from the leaves and factor cuts
+        for ( i = RandLeaf; i < Vec_PtrSize(vLeaves)-1; i++ )
+        {
+            Vec_PtrWriteEntry( vLeaves,  i, Vec_PtrEntry(vLeaves, i+1) );
+            Vec_PtrWriteEntry( vFactors, i, Vec_PtrEntry(vFactors,i+1) );
+        }
+        Vec_PtrShrink( vLeaves,  Vec_PtrSize(vLeaves) -1 );
+        Vec_PtrShrink( vFactors, Vec_PtrSize(vFactors)-1 );
+        // add new leaves, compute their factor cuts
+        Vec_PtrForEachEntry( vNext, pLeaf, i )
+        {
+            if ( Abc_NodeIsTravIdCurrent(pLeaf) )
+                continue;
+            Abc_NodeSetTravIdCurrent( pLeaf ); 
+            Vec_PtrPush( vLeaves, pLeaf );
+            if ( Abc_ObjIsCi(pLeaf) )
+                Vec_PtrPush( vFactors, NULL );
+            else
+                Vec_PtrPush( vFactors, Abc_CutFactor(pLeaf) );
+        }
+        Vec_PtrFree( vNext );
+        assert( Vec_PtrSize(vLeaves) <= nLeavesMax );
+        if ( Vec_PtrSize(vLeaves) == nLeavesMax )
+            break;
+    }
+
+    // remove temporary storage
+    Vec_PtrForEachEntry( vFactors, vFact, i )
+        if ( vFact ) Vec_PtrFree( vFact );
+    Vec_PtrFree( vFactors );
+    Vec_IntFree( vFeasible );
+    return vLeaves;
+}
+
+////////////////////////////////////////////////////////////////////////
+///                       END OF FILE                                ///
+////////////////////////////////////////////////////////////////////////
+
+