acbMfs.c

/**CFile****************************************************************

  FileName    [abcMfs.c]

  SystemName  [ABC: Logic synthesis and verification system.]

  PackageName [Hierarchical word-level netlist.]

  Synopsis    [Optimization with don't-cares.]

  Author      [Alan Mishchenko]
  
  Affiliation [UC Berkeley]

  Date        [Ver. 1.0. Started - July 21, 2015.]

  Revision    [$Id: abcMfs.c,v 1.00 2014/11/29 00:00:00 alanmi Exp $]

***********************************************************************/

#include "acb.h"
#include "bool/kit/kit.h"
#include "sat/bsat/satSolver.h"
#include "sat/cnf/cnf.h"
#include "misc/util/utilTruth.h"
#include "acbPar.h"

ABC_NAMESPACE_IMPL_START

////////////////////////////////////////////////////////////////////////
///                        DECLARATIONS                              ///
////////////////////////////////////////////////////////////////////////

static inline int Acb_ObjIsDelayCriticalFanin( Acb_Ntk_t * p, int i, int f )  { return !Acb_ObjIsCi(p, f) && Acb_ObjLevelR(p, i) + Acb_ObjLevelD(p, f) == p->LevelMax; }
static inline int Acb_ObjIsAreaCritical( Acb_Ntk_t * p, int f )               { return !Acb_ObjIsCi(p, f) && Acb_ObjFanoutNum(p, f) == 1;                              }
static inline int Acb_ObjIsCritical( Acb_Ntk_t * p, int i, int f, int fDel )  { return fDel ? Acb_ObjIsDelayCriticalFanin(p, i, f) : Acb_ObjIsAreaCritical(p, f);      }

////////////////////////////////////////////////////////////////////////
///                     FUNCTION DEFINITIONS                         ///
////////////////////////////////////////////////////////////////////////

/**Function*************************************************************

  Synopsis    [Derive CNF for nodes in the window.]

  Description []
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
int Acb_DeriveCnfFromTruth( word Truth, int nVars, Vec_Int_t * vCover, Vec_Str_t * vCnf )
{
    Vec_StrClear( vCnf );
    if ( Truth == 0 || ~Truth == 0 )
    {
//        assert( nVars == 0 );
        Vec_StrPush( vCnf, (char)(Truth == 0) );
        Vec_StrPush( vCnf, (char)-1 );
        return 1;
    }
    else 
    {
        int i, k, c, RetValue, Literal, Cube, nCubes = 0;
        assert( nVars > 0 );
        for ( c = 0; c < 2; c ++ )
        {
            Truth = c ? ~Truth : Truth;
            RetValue = Kit_TruthIsop( (unsigned *)&Truth, nVars, vCover, 0 );
            assert( RetValue == 0 );
            nCubes += Vec_IntSize( vCover );
            Vec_IntForEachEntry( vCover, Cube, i )
            {
                for ( k = 0; k < nVars; k++ )
                {
                    Literal = 3 & (Cube >> (k << 1));
                    if ( Literal == 1 )      // '0'  -> pos lit
                        Vec_StrPush( vCnf, (char)Abc_Var2Lit(k, 0) );
                    else if ( Literal == 2 ) // '1'  -> neg lit
                        Vec_StrPush( vCnf, (char)Abc_Var2Lit(k, 1) );
                    else if ( Literal != 0 )
                        assert( 0 );
                }
                Vec_StrPush( vCnf, (char)Abc_Var2Lit(nVars, c) );
                Vec_StrPush( vCnf, (char)-1 );
            }
        }
        return nCubes;
    }
}

void Acb_DeriveCnfForWindowOne( Acb_Ntk_t * p, int iObj )
{
    Vec_Wec_t * vCnfs = &p->vCnfs;
    Vec_Str_t * vCnfBase = Acb_ObjCnfs( p, iObj );
    assert( Vec_StrSize(vCnfBase) == 0 ); // unassigned
    assert( Vec_WecSize(vCnfs) == Acb_NtkObjNumMax(p) );
    Acb_DeriveCnfFromTruth( Acb_ObjTruth(p, iObj), Acb_ObjFaninNum(p, iObj), &p->vCover, &p->vCnf );
    Vec_StrGrow( vCnfBase, Vec_StrSize(&p->vCnf) );
    memcpy( Vec_StrArray(vCnfBase), Vec_StrArray(&p->vCnf), (size_t)Vec_StrSize(&p->vCnf) );
    vCnfBase->nSize = Vec_StrSize(&p->vCnf);
}
Vec_Wec_t * Acb_DeriveCnfForWindow( Acb_Ntk_t * p, Vec_Int_t * vWin, int PivotVar )
{
    Vec_Wec_t * vCnfs = &p->vCnfs;
    Vec_Str_t * vCnfBase; int i, iObj;
    assert( Vec_WecSize(vCnfs) == Acb_NtkObjNumMax(p) );
    Vec_IntForEachEntry( vWin, iObj, i )
    {
        if ( Abc_LitIsCompl(iObj) && i < PivotVar )
            continue;
        iObj = Abc_Lit2Var(iObj);
        vCnfBase = Acb_ObjCnfs( p, iObj );
        if ( Vec_StrSize(vCnfBase) > 0 )
            continue;
        Acb_DeriveCnfForWindowOne( p, iObj );
    }
    return vCnfs;
}

/**Function*************************************************************

  Synopsis    [Constructs CNF for the window.]

  Description [The window for the pivot node is represented as a DFS ordered array 
  of objects (vWinObjs) whose indexes are used as SAT variable IDs (stored in p->vCopies).
  PivotVar is the index of the pivot node in array vWinObjs.
  The nodes before (after) PivotVar are TFI (TFO) nodes.
  The leaf (root) nodes are labeled with Abc_LitIsCompl().
  If fQbf is 1, returns the instance meant for QBF solving. It uses the last 
  variable (LastVar) as the placeholder for the second copy of the pivot node.]
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
void Acb_TranslateCnf( Vec_Int_t * vClas, Vec_Int_t * vLits, Vec_Str_t * vCnf, Vec_Int_t * vSatVars, int iPivotVar )
{
    signed char Entry;
    int i, Lit;
    Vec_StrForEachEntry( vCnf, Entry, i )
    {
        if ( (int)Entry == -1 )
        {
            Vec_IntPush( vClas, Vec_IntSize(vLits) );
            continue;
        }
        Lit = Abc_Lit2LitV( Vec_IntArray(vSatVars), (int)Entry );
        Lit = Abc_LitNotCond( Lit, Abc_Lit2Var(Lit) == iPivotVar );
        Vec_IntPush( vLits, Lit );
    }
}
int Acb_NtkCountRoots( Vec_Int_t * vWinObjs, int PivotVar )
{
    int i, iObjLit, nRoots = 0;
    Vec_IntForEachEntryStart( vWinObjs, iObjLit, i, PivotVar + 1 )
        nRoots += Abc_LitIsCompl(iObjLit);
    return nRoots;
}
void Acb_DeriveCnfForNode( Acb_Ntk_t * p, int iObj, sat_solver * pSat, int OutVar )
{
    Vec_Wec_t * vCnfs = &p->vCnfs;
    Vec_Int_t * vFaninVars = &p->vCover;
    Vec_Int_t * vClas = Vec_IntAlloc( 100 );
    Vec_Int_t * vLits = Vec_IntAlloc( 100 );
    int k, iFanin, * pFanins, Prev, This;
    // collect SAT variables
    Vec_IntClear( vFaninVars );
    Acb_ObjForEachFaninFast( p, iObj, pFanins, iFanin, k )
    {
        assert( Acb_ObjFunc(p, iFanin) >= 0 );
        Vec_IntPush( vFaninVars, Acb_ObjFunc(p, iFanin) );
    }
    Vec_IntPush( vFaninVars, OutVar );
    // derive CNF for the node
    Acb_TranslateCnf( vClas, vLits, (Vec_Str_t *)Vec_WecEntry(vCnfs, iObj), vFaninVars, -1 );
    // add clauses
    Prev = 0;
    Vec_IntForEachEntry( vClas, This, k )
    {
        if ( !sat_solver_addclause( pSat, Vec_IntArray(vLits) + Prev, Vec_IntArray(vLits) + This ) )
            printf( "Error: SAT solver became UNSAT at a wrong place (while adding new CNF).\n" );
        Prev = This;
    }
    Vec_IntFree( vClas );
    Vec_IntFree( vLits );
}
Cnf_Dat_t * Acb_NtkWindow2Cnf( Acb_Ntk_t * p, Vec_Int_t * vWinObjs, int Pivot )
{
    Cnf_Dat_t * pCnf;
    Vec_Int_t * vFaninVars = Vec_IntAlloc( 8 );
    int PivotVar = Vec_IntFind(vWinObjs, Abc_Var2Lit(Pivot, 0));
    int nRoots   = Acb_NtkCountRoots(vWinObjs, PivotVar);
    int TfoStart = PivotVar + 1;
    int nTfoSize = Vec_IntSize(vWinObjs) - TfoStart;
    int nVarsAll = Vec_IntSize(vWinObjs) + nTfoSize + nRoots;
    int i, k, iObj, iObjLit, iFanin, * pFanins, Entry;
    Vec_Wec_t * vCnfs = Acb_DeriveCnfForWindow( p, vWinObjs, PivotVar );
    Vec_Int_t * vClas = Vec_IntAlloc( 100 );
    Vec_Int_t * vLits = Vec_IntAlloc( 1000 );
    // mark new SAT variables
    Vec_IntForEachEntry( vWinObjs, iObj, i )
        Acb_ObjSetFunc( p, Abc_Lit2Var(iObj), i );
    // add clauses for all nodes
    Vec_IntPush( vClas, Vec_IntSize(vLits) );
    Vec_IntForEachEntry( vWinObjs, iObjLit, i )
    {
        if ( Abc_LitIsCompl(iObjLit) && i < PivotVar )
            continue;
        iObj = Abc_Lit2Var(iObjLit);
        assert( !Acb_ObjIsCio(p, iObj) );
        // collect SAT variables
        Vec_IntClear( vFaninVars );
        Acb_ObjForEachFaninFast( p, iObj, pFanins, iFanin, k )
            Vec_IntPush( vFaninVars, Acb_ObjFunc(p, iFanin) );
        Vec_IntPush( vFaninVars, Acb_ObjFunc(p, iObj) );
        // derive CNF for the node
        Acb_TranslateCnf( vClas, vLits, (Vec_Str_t *)Vec_WecEntry(vCnfs, iObj), vFaninVars, -1 );
    }
    // add second clauses for the TFO
    Vec_IntForEachEntryStart( vWinObjs, iObjLit, i, TfoStart )
    {
        iObj = Abc_Lit2Var(iObjLit);
        assert( !Acb_ObjIsCio(p, iObj) );
        // collect SAT variables
        Vec_IntClear( vFaninVars );
        Acb_ObjForEachFaninFast( p, iObj, pFanins, iFanin, k )
            Vec_IntPush( vFaninVars, Acb_ObjFunc(p, iFanin) + (Acb_ObjFunc(p, iFanin) > PivotVar) * nTfoSize );
        Vec_IntPush( vFaninVars, Acb_ObjFunc(p, iObj) + nTfoSize );
        // derive CNF for the node
        Acb_TranslateCnf( vClas, vLits, (Vec_Str_t *)Vec_WecEntry(vCnfs, iObj), vFaninVars, PivotVar );
    }
    if ( nRoots > 0 )
    {
        // create XOR clauses for the roots
        int nVars = Vec_IntSize(vWinObjs) + nTfoSize;
        Vec_IntClear( vFaninVars );
        Vec_IntForEachEntryStart( vWinObjs, iObjLit, i, TfoStart )
        {
            if ( !Abc_LitIsCompl(iObjLit) )
                continue;
            iObj = Abc_Lit2Var(iObjLit);
            // add clauses
            Vec_IntPushThree( vLits, Abc_Var2Lit(Acb_ObjFunc(p, iObj), 1), Abc_Var2Lit(Acb_ObjFunc(p, iObj) + nTfoSize, 0), Abc_Var2Lit(nVars, 0) );
            Vec_IntPush( vClas, Vec_IntSize(vLits) );
            Vec_IntPushThree( vLits, Abc_Var2Lit(Acb_ObjFunc(p, iObj), 0), Abc_Var2Lit(Acb_ObjFunc(p, iObj) + nTfoSize, 1), Abc_Var2Lit(nVars, 0) );
            Vec_IntPush( vClas, Vec_IntSize(vLits) );
            Vec_IntPushThree( vLits, Abc_Var2Lit(Acb_ObjFunc(p, iObj), 0), Abc_Var2Lit(Acb_ObjFunc(p, iObj) + nTfoSize, 0), Abc_Var2Lit(nVars, 1) );
            Vec_IntPush( vClas, Vec_IntSize(vLits) );
            Vec_IntPushThree( vLits, Abc_Var2Lit(Acb_ObjFunc(p, iObj), 1), Abc_Var2Lit(Acb_ObjFunc(p, iObj) + nTfoSize, 1), Abc_Var2Lit(nVars, 1) );
            Vec_IntPush( vClas, Vec_IntSize(vLits) );
            Vec_IntPush( vFaninVars, Abc_Var2Lit(nVars++, 0) );
        }
        Vec_IntAppend( vLits, vFaninVars );
        Vec_IntPush( vClas, Vec_IntSize(vLits) );
        assert( nRoots == Vec_IntSize(vFaninVars) );
        assert( nVars == nVarsAll );
    }
    Vec_IntFree( vFaninVars );
    // create CNF structure
    pCnf = ABC_CALLOC( Cnf_Dat_t, 1 );
    pCnf->nVars     = nVarsAll;
    pCnf->nClauses  = Vec_IntSize(vClas)-1;
    pCnf->nLiterals = Vec_IntSize(vLits);
    pCnf->pClauses  = ABC_ALLOC( int *, Vec_IntSize(vClas) );
    pCnf->pClauses[0] = Vec_IntReleaseArray(vLits);
    Vec_IntForEachEntry( vClas, Entry, i )
        pCnf->pClauses[i] = pCnf->pClauses[0] + Entry;
    // cleanup
    Vec_IntFree( vClas );
    Vec_IntFree( vLits );
    //Cnf_DataPrint( pCnf, 1 );
    return pCnf;
}
void Acb_NtkWindowUndo( Acb_Ntk_t * p, Vec_Int_t * vWin )
{
    int i, iObj;
    Vec_IntForEachEntry( vWin, iObj, i )
    {
        assert( Vec_IntEntry(&p->vObjFunc, Abc_Lit2Var(iObj)) != -1 );
        Vec_IntWriteEntry( &p->vObjFunc, Abc_Lit2Var(iObj), -1 );
    }
}

/**Function*************************************************************

  Synopsis    [Creates SAT solver containing several copies of the window.]

  Description []
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
int Acb_NtkWindow2Solver( sat_solver * pSat, Cnf_Dat_t * pCnf, Vec_Int_t * vFlip, int PivotVar, int nDivs, int nTimes )
{
    int n, i, RetValue, Test = pCnf->pClauses[0][0];
    int nGroups = nTimes <= 2 ? nTimes-1 : 2;
    int nRounds = nTimes <= 2 ? nTimes-1 : nTimes;
    assert( sat_solver_nvars(pSat) == 0 );
    sat_solver_setnvars( pSat, nTimes * pCnf->nVars + nGroups * nDivs + 2 );
    assert( nTimes == 1 || nTimes == 2 || nTimes == 6 );
    for ( n = 0; n < nTimes; n++ )
    {
        if ( n & 1 )
            Cnf_DataLiftAndFlipLits( pCnf, -pCnf->nVars, vFlip );
        for ( i = 0; i < pCnf->nClauses; i++ )
            if ( !sat_solver_addclause( pSat, pCnf->pClauses[i], pCnf->pClauses[i+1] ) )
                printf( "Error: SAT solver became UNSAT at a wrong place.\n" );
        if ( n & 1 )
            Cnf_DataLiftAndFlipLits( pCnf, pCnf->nVars, vFlip );
        if ( n < nTimes - 1 )
            Cnf_DataLift( pCnf, pCnf->nVars );
        else if ( n ) // if ( n == nTimes - 1 )
            Cnf_DataLift( pCnf, -(nTimes - 1) * pCnf->nVars );
    }
    assert( Test == pCnf->pClauses[0][0] );
    // add conditional buffers
    for ( n = 0; n < nRounds; n++ )
    {
        int BaseA = n * pCnf->nVars;
        int BaseB = ((n + 1) % nTimes) * pCnf->nVars;
        int BaseC = nTimes * pCnf->nVars + (n & 1) * nDivs;
        for ( i = 0; i < nDivs; i++ )
            sat_solver_add_buffer_enable( pSat, BaseA + i, BaseB + i, BaseC + i, 0 );
    }
    // finalize
    RetValue = sat_solver_simplify( pSat );
    if ( !RetValue ) printf( "Error: SAT solver became UNSAT at a wrong place.\n" );
    return 1;
}

/**Function*************************************************************

  Synopsis    [Computes function of the node]

  Description []
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
word Acb_ComputeFunction( sat_solver * pSat, int PivotVar, int FreeVar, Vec_Int_t * vDivVars, int fCompl )
{
    int fExpand = 0;
    word uCube, uTruth = 0;
    Vec_Int_t * vTempLits = Vec_IntAlloc( 100 );
    int status, i, iVar, iLit, nFinal, * pFinal, pLits[2];
    assert( FreeVar < sat_solver_nvars(pSat) );
//    if ( fCompl )
//        pLits[0] = Abc_Var2Lit( sat_solver_nvars(pSat)-2, 0 ); // F = 1
//    else
        pLits[0] = Abc_Var2Lit( PivotVar, fCompl ); // F = 1
    pLits[1] = Abc_Var2Lit( FreeVar, 0 );  // iNewLit
    while ( 1 ) 
    {
        // find onset minterm
        status = sat_solver_solve( pSat, pLits, pLits + 2, 0, 0, 0, 0 );
        if ( status == l_False )
        {
            Vec_IntFree( vTempLits );
            return uTruth;
        }
        assert( status == l_True );
        if ( fExpand )
        {
            // collect divisor literals
            Vec_IntFill( vTempLits, 1, Abc_LitNot(pLits[0]) ); // F = 0
            Vec_IntForEachEntry( vDivVars, iVar, i )
                Vec_IntPush( vTempLits, sat_solver_var_literal(pSat, iVar) );
            // check against offset
            status = sat_solver_solve( pSat, Vec_IntArray(vTempLits), Vec_IntLimit(vTempLits), 0, 0, 0, 0 );
            if ( status != l_False )
                printf( "Failed internal check during function comptutation.\n" );
            assert( status == l_False );
            // compute cube and add clause
            nFinal = sat_solver_final( pSat, &pFinal );
            Vec_IntFill( vTempLits, 1, Abc_LitNot(pLits[1]) ); // NOT(iNewLit)
            for ( i = 0; i < nFinal; i++ )
                if ( pFinal[i] != pLits[0] )
                    Vec_IntPush( vTempLits, pFinal[i] );
        }
        else
        {
            // collect divisor literals
            Vec_IntFill( vTempLits, 1, Abc_LitNot(pLits[1]) );// NOT(iNewLit)
            Vec_IntForEachEntry( vDivVars, iVar, i )
                Vec_IntPush( vTempLits, Abc_LitNot(sat_solver_var_literal(pSat, iVar)) );
        }
        uCube = ~(word)0;
        Vec_IntForEachEntryStart( vTempLits, iLit, i, 1 )
        {
            iVar = Vec_IntFind( vDivVars, Abc_Lit2Var(iLit) );   assert( iVar >= 0 );
            uCube &= Abc_LitIsCompl(iLit) ? s_Truths6[iVar] : ~s_Truths6[iVar];
        }
        uTruth |= uCube;
        status = sat_solver_addclause( pSat, Vec_IntArray(vTempLits), Vec_IntLimit(vTempLits) );
        if ( status == 0 )
        {
            Vec_IntFree( vTempLits );
            return uTruth;
        }
    }
    Vec_IntFree( vTempLits );
    assert( 0 ); 
    return ~(word)0;
}





/**Function*************************************************************

  Synopsis    []

  Description []
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
void Acb_NtkPrintVec( Acb_Ntk_t * p, Vec_Int_t * vVec, char * pName )
{
    int i;
    printf( "%s: ", pName );
    for ( i = 0; i < vVec->nSize; i++ )
        printf( "%d ", vVec->pArray[i] );
    printf( "\n" );
}
void Acb_NtkPrintVec2( Acb_Ntk_t * p, Vec_Int_t * vVec, char * pName )
{
    int i;
    printf( "%s: \n", pName );
    for ( i = 0; i < vVec->nSize; i++ )
        Acb_NtkPrintNode( p, vVec->pArray[i] );
    printf( "\n" );
}
void Acb_NtkPrintVecWin( Acb_Ntk_t * p, Vec_Int_t * vVec, char * pName )
{
    int i;
    printf( "%s: \n", pName );
    for ( i = 0; i < vVec->nSize; i++ )
        Acb_NtkPrintNode( p, Abc_Lit2Var(vVec->pArray[i]) );
    printf( "\n" );
}

/**Function*************************************************************

  Synopsis    [Collects divisors in a non-topo order.]

  Description []
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
void Acb_NtkDivisors_rec( Acb_Ntk_t * p, int iObj, int nTfiLevMin, Vec_Int_t * vDivs )
{
    int k, iFanin, * pFanins;
//    if ( !Acb_ObjIsCi(p, iObj) && Acb_ObjLevelD(p, iObj) < nTfiLevMin )
    if ( !Acb_ObjIsCi(p, iObj) && nTfiLevMin < 0 )
        return;
    if ( Acb_ObjSetTravIdCur(p, iObj) )
        return;
    Acb_ObjForEachFaninFast( p, iObj, pFanins, iFanin, k )
        Acb_NtkDivisors_rec( p, iFanin, nTfiLevMin-1, vDivs );
    Vec_IntPush( vDivs, iObj );
}
Vec_Int_t * Acb_NtkDivisors( Acb_Ntk_t * p, int Pivot, int nTfiLevMin, int fDelay )
{
    int k, iFanin, * pFanins;
    Vec_Int_t * vDivs = Vec_IntAlloc( 100 );
    Acb_NtkIncTravId( p );
//    if ( fDelay ) // delay-oriented
    if ( 0 ) // delay-oriented
    {
        // start from critical fanins
        assert( Acb_ObjLevelD( p, Pivot ) > 1 );
        Acb_ObjForEachFaninFast( p, Pivot, pFanins, iFanin, k )
            if ( Acb_ObjIsDelayCriticalFanin( p, Pivot, iFanin ) )
                Acb_NtkDivisors_rec( p, iFanin, nTfiLevMin, vDivs );
        // add non-critical fanins
        Acb_ObjForEachFaninFast( p, Pivot, pFanins, iFanin, k )
            if ( !Acb_ObjIsDelayCriticalFanin( p, Pivot, iFanin ) )
                if ( !Acb_ObjSetTravIdCur(p, iFanin) )
                    Vec_IntPush( vDivs, iFanin );
    }
    else
    {
        Acb_NtkDivisors_rec( p, Pivot, nTfiLevMin, vDivs );
        assert( Vec_IntEntryLast(vDivs) == Pivot );
        Vec_IntPop( vDivs );
        // add remaining fanins of the node
        Acb_ObjForEachFaninFast( p, Pivot, pFanins, iFanin, k )
            if ( !Acb_ObjSetTravIdCur(p, iFanin) )
                Vec_IntPush( vDivs, iFanin );
/*
        // start from critical fanins
        assert( Acb_ObjLevelD( p, Pivot ) > 1 );
        Acb_ObjForEachFaninFast( p, Pivot, pFanins, iFanin, k )
            if ( Acb_ObjIsAreaCritical( p, iFanin ) )
                Acb_NtkDivisors_rec( p, iFanin, nTfiLevMin, vDivs );
        // add non-critical fanins
        Acb_ObjForEachFaninFast( p, Pivot, pFanins, iFanin, k )
            if ( !Acb_ObjIsAreaCritical( p, iFanin ) )
                if ( !Acb_ObjSetTravIdCur(p, iFanin) )
                    Vec_IntPush( vDivs, iFanin );
*/
    }
    return vDivs;
}

/**Function*************************************************************

  Synopsis    [Marks TFO of divisors.]

  Description []
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
void Acb_ObjMarkTfo_rec( Acb_Ntk_t * p, int iObj, int nTfoLevMax, int nFanMax, Vec_Int_t * vMarked )
{
    int iFanout, i;
    if ( Acb_ObjSetTravIdCur(p, iObj) )
        return;
    Vec_IntPush( vMarked, iObj );
    if ( Acb_ObjLevelD(p, iObj) > nTfoLevMax || Acb_ObjFanoutNum(p, iObj) > nFanMax )
        return;
    Acb_ObjForEachFanout( p, iObj, iFanout, i )
        Acb_ObjMarkTfo_rec( p, iFanout, nTfoLevMax, nFanMax, vMarked );
}
Vec_Int_t * Acb_ObjMarkTfo( Acb_Ntk_t * p, Vec_Int_t * vDivs, int Pivot, int nTfoLevMax, int nFanMax )
{
    Vec_Int_t * vMarked = Vec_IntAlloc( 1000 );
    int i, iObj;
    Acb_NtkIncTravId( p );
    Acb_ObjSetTravIdCur( p, Pivot );
    Vec_IntPush( vMarked, Pivot );
    Vec_IntForEachEntry( vDivs, iObj, i )
        Acb_ObjMarkTfo_rec( p, iObj, nTfoLevMax, nFanMax, vMarked );
    return vMarked;
}
void Acb_ObjMarkTfo2( Acb_Ntk_t * p, Vec_Int_t * vMarked )
{
    int i, Node;
    Acb_NtkIncTravId( p );
    Vec_IntForEachEntry( vMarked, Node, i )
        Acb_ObjSetTravIdCur( p, Node );
}

/**Function*************************************************************

  Synopsis    [Labels TFO nodes with {none, root, inner} based on their type.]

  Description [Assuming TFO of TFI is marked with the current trav ID.]
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
int Acb_ObjLabelTfo_rec( Acb_Ntk_t * p, int iObj, int nTfoLevMax, int nFanMax, int fFirst )
{
    int iFanout, i, Diff, fHasNone = 0;
    if ( (Diff = Acb_ObjTravIdDiff(p, iObj)) <= 2 )
        return Diff;
    Acb_ObjSetTravIdDiff( p, iObj, 2 );
    if ( Acb_ObjIsCo(p, iObj) || Acb_ObjLevelD(p, iObj) > nTfoLevMax )
        return 2;
    if ( Acb_ObjLevelD(p, iObj) == nTfoLevMax || Acb_ObjFanoutNum(p, iObj) > nFanMax )
    {
        if ( Diff == 3 )  // belongs to TFO of TFI
            Acb_ObjSetTravIdDiff( p, iObj, 1 ); // root
        return Acb_ObjTravIdDiff(p, iObj);
    }
    Acb_ObjForEachFanout( p, iObj, iFanout, i )
        if ( !fFirst || Acb_ObjIsDelayCriticalFanin(p, iFanout, iObj) )
            fHasNone |= 2 == Acb_ObjLabelTfo_rec( p, iFanout, nTfoLevMax, nFanMax, 0 );
    if ( fHasNone && Diff == 3 )  // belongs to TFO of TFI
        Acb_ObjSetTravIdDiff( p, iObj, 1 ); // root
    else if ( !fHasNone )
        Acb_ObjSetTravIdDiff( p, iObj, 0 ); // inner
    return Acb_ObjTravIdDiff(p, iObj);
}
int Acb_ObjLabelTfo( Acb_Ntk_t * p, int Root, int nTfoLevMax, int nFanMax, int fDelay )
{
    Acb_NtkIncTravId( p ); // none  (2)    marked (3)  unmarked (4)
    Acb_NtkIncTravId( p ); // root  (1)
    Acb_NtkIncTravId( p ); // inner (0)
    assert( Acb_ObjTravIdDiff(p, Root) > 2 );
    return Acb_ObjLabelTfo_rec( p, Root, nTfoLevMax, nFanMax, fDelay );
}

/**Function*************************************************************

  Synopsis    [Collects labeled TFO.]

  Description []
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
void Acb_ObjDeriveTfo_rec( Acb_Ntk_t * p, int iObj, Vec_Int_t * vTfo, Vec_Int_t * vRoots, int fFirst )
{
    int iFanout, i, Diff = Acb_ObjTravIdDiff(p, iObj);
    if ( Acb_ObjSetTravIdCur(p, iObj) )
        return;
    if ( Diff == 2 ) // root
    {
        Vec_IntPush( vRoots, iObj );
        Vec_IntPush( vTfo, iObj );
        return;
    }
    assert( Diff == 1 );
    Acb_ObjForEachFanout( p, iObj, iFanout, i )
        if ( !fFirst || Acb_ObjIsDelayCriticalFanin(p, iFanout, iObj) )
            Acb_ObjDeriveTfo_rec( p, iFanout, vTfo, vRoots, 0 );
    Vec_IntPush( vTfo, iObj );
}
void Acb_ObjDeriveTfo( Acb_Ntk_t * p, int Pivot, int nTfoLevMax, int nFanMax, Vec_Int_t ** pvTfo, Vec_Int_t ** pvRoots, int fDelay )
{
    int Res = Acb_ObjLabelTfo( p, Pivot, nTfoLevMax, nFanMax, fDelay );
    Vec_Int_t * vTfo   = *pvTfo   = Vec_IntAlloc( 10 );
    Vec_Int_t * vRoots = *pvRoots = Vec_IntAlloc( 10 );
    if ( Res ) // none or root
        return;
    Acb_NtkIncTravId( p ); // root (2)   inner (1)  visited (0)
    Acb_ObjDeriveTfo_rec( p, Pivot, vTfo, vRoots, fDelay );
    assert( Vec_IntEntryLast(vTfo) == Pivot );
    Vec_IntPop( vTfo );
    assert( Vec_IntEntryLast(vRoots) != Pivot );
    Vec_IntReverseOrder( vTfo );
    Vec_IntReverseOrder( vRoots );
}


/**Function*************************************************************

  Synopsis    [Collect side-inputs of the TFO, except the node.]

  Description []
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
Vec_Int_t * Acb_NtkCollectTfoSideInputs( Acb_Ntk_t * p, int Pivot, Vec_Int_t * vTfo )
{
    Vec_Int_t * vSide  = Vec_IntAlloc( 100 );
    int i, k, Node, iFanin, * pFanins;
    Acb_NtkIncTravId( p );
    Vec_IntPush( vTfo, Pivot );
    Vec_IntForEachEntry( vTfo, Node, i )
        Acb_ObjSetTravIdCur( p, Node );
    Vec_IntForEachEntry( vTfo, Node, i )
        Acb_ObjForEachFaninFast( p, Node, pFanins, iFanin, k )
            if ( !Acb_ObjSetTravIdCur(p, iFanin) && iFanin != Pivot )
                Vec_IntPush( vSide, iFanin );
    Vec_IntPop( vTfo );
    return vSide;
}

/**Function*************************************************************

  Synopsis    [From side inputs, collect marked nodes and their unmarked fanins.]

  Description []
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
void Acb_NtkCollectNewTfi1_rec( Acb_Ntk_t * p, int iObj, Vec_Int_t * vTfiNew )
{
    int i, iFanin, * pFanins;
    if ( !Acb_ObjIsTravIdPrev(p, iObj) )
        return;
    if ( Acb_ObjSetTravIdCur(p, iObj) )
        return;
    Acb_ObjForEachFaninFast( p, iObj, pFanins, iFanin, i )
        Acb_NtkCollectNewTfi1_rec( p, iFanin, vTfiNew );
    Vec_IntPush( vTfiNew, iObj );
}
void Acb_NtkCollectNewTfi2_rec( Acb_Ntk_t * p, int iObj, Vec_Int_t * vTfiNew )
{
    int i, iFanin, * pFanins;
    int fTravIdPrev = Acb_ObjIsTravIdPrev(p, iObj);
    if ( Acb_ObjSetTravIdCur(p, iObj) )
        return;
    if ( fTravIdPrev && !Acb_ObjIsCi(p, iObj) )
        Acb_ObjForEachFaninFast( p, iObj, pFanins, iFanin, i )
            Acb_NtkCollectNewTfi2_rec( p, iFanin, vTfiNew );
    Vec_IntPush( vTfiNew, iObj );
}
Vec_Int_t * Acb_NtkCollectNewTfi( Acb_Ntk_t * p, int Pivot, Vec_Int_t * vDivs, Vec_Int_t * vSide, int * pnDivs )
{
    Vec_Int_t * vTfiNew  = Vec_IntAlloc( 100 );
    int i, Node;
    Acb_NtkIncTravId( p );
    //Acb_NtkPrintVec( p, vDivs, "vDivs" );
    Vec_IntForEachEntry( vDivs, Node, i )
        Acb_NtkCollectNewTfi1_rec( p, Node, vTfiNew );
//Acb_NtkPrintVec( p, vTfiNew, "vTfiNew" );
    Acb_NtkCollectNewTfi1_rec( p, Pivot, vTfiNew );
//Acb_NtkPrintVec( p, vTfiNew, "vTfiNew" );
    assert( Vec_IntEntryLast(vTfiNew) == Pivot );
    Vec_IntPop( vTfiNew );
/*
    Vec_IntForEachEntry( vDivs, Node, i )
    {
        Acb_ObjSetTravIdCur( p, Node );
        Vec_IntPush( vTfiNew, Node );
    }
*/
    *pnDivs = Vec_IntSize(vTfiNew);
    Vec_IntForEachEntry( vSide, Node, i )
        Acb_NtkCollectNewTfi2_rec( p, Node, vTfiNew );
    Vec_IntPush( vTfiNew, Pivot );
    return vTfiNew;
}

/**Function*************************************************************

  Synopsis    []

  Description []
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
Vec_Int_t * Acb_NtkCollectWindow( Acb_Ntk_t * p, int Pivot, Vec_Int_t * vTfi, Vec_Int_t * vTfo, Vec_Int_t * vRoots )
{
    Vec_Int_t * vWin = Vec_IntAlloc( 100 );
    int i, k, iObj, iFanin, * pFanins;
    assert( Vec_IntEntryLast(vTfi) == Pivot );
    // mark nodes
    Acb_NtkIncTravId( p );
    Vec_IntForEachEntry( vTfi, iObj, i )
        Acb_ObjSetTravIdCur(p, iObj);
    // add TFI
    Vec_IntForEachEntry( vTfi, iObj, i )
    {
        int fIsTfiInput = 0;
        Acb_ObjForEachFaninFast( p, iObj, pFanins, iFanin, k )
            if ( !Acb_ObjIsTravIdCur(p, iFanin) ) // fanin is not in TFI
                fIsTfiInput = 1; // mark as leaf
        Vec_IntPush( vWin, Abc_Var2Lit(iObj, Acb_ObjIsCi(p, iObj) || fIsTfiInput) );
    }
    // mark roots
    Acb_NtkIncTravId( p );
    Vec_IntForEachEntry( vRoots, iObj, i )
        Acb_ObjSetTravIdCur(p, iObj);
    // add TFO
    Vec_IntForEachEntry( vTfo, iObj, i )
    {
        assert( !Acb_ObjIsCo(p, iObj) );
        Vec_IntPush( vWin, Abc_Var2Lit(iObj, Acb_ObjIsTravIdCur(p, iObj)) );
    }
    return vWin;
}

/**Function*************************************************************

  Synopsis    []

  Description []
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
Vec_Int_t * Acb_NtkWindow( Acb_Ntk_t * p, int Pivot, int nTfiLevs, int nTfoLevs, int nFanMax, int fDelay, int * pnDivs )
{
    int fVerbose = 0;
    //int nTfiLevMin = Acb_ObjLevelD(p, Pivot) - nTfiLevs;
    int nTfoLevMax = Acb_ObjLevelD(p, Pivot) + nTfoLevs;
    Vec_Int_t * vWin, * vDivs, * vMarked, * vTfo, * vRoots, * vSide, * vTfi;
    // collect divisors by traversing limited TFI
    vDivs = Acb_NtkDivisors( p, Pivot, nTfiLevs, fDelay );
    if ( fVerbose ) Acb_NtkPrintVec( p, vDivs, "vDivs" );
    // mark limited TFO of the divisors
    vMarked = Acb_ObjMarkTfo( p, vDivs, Pivot, nTfoLevMax, nFanMax );
    // collect TFO and roots
    Acb_ObjDeriveTfo( p, Pivot, nTfoLevMax, nFanMax, &vTfo, &vRoots, 0 );//fDelay );
    if ( fVerbose ) Acb_NtkPrintVec( p, vTfo, "vTfo" );
    if ( fVerbose ) Acb_NtkPrintVec( p, vRoots, "vRoots" );
    // collect side inputs of the TFO
    vSide = Acb_NtkCollectTfoSideInputs( p, Pivot, vTfo );
    if ( fVerbose ) Acb_NtkPrintVec( p, vSide, "vSide" );
    // mark limited TFO of the divisors
    //Acb_ObjMarkTfo( p, vDivs, Pivot, nTfoLevMax, nFanMax );
    Acb_ObjMarkTfo2( p, vMarked );
    Vec_IntFree( vMarked );
    // collect new TFI
    vTfi = Acb_NtkCollectNewTfi( p, Pivot, vDivs, vSide, pnDivs );
    if ( fVerbose ) Acb_NtkPrintVec( p, vTfi, "vTfi" );
    Vec_IntFree( vSide );
    Vec_IntFree( vDivs );
    // collect all nodes
    vWin = Acb_NtkCollectWindow( p, Pivot, vTfi, vTfo, vRoots );
    // cleanup
    Vec_IntFree( vTfi );
    Vec_IntFree( vTfo );
    Vec_IntFree( vRoots );
    return vWin;
}



/**Function*************************************************************

  Synopsis    []

  Description []
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
static inline void Vec_IntVars2Vars( Vec_Int_t * p, int Shift )
{
    int i;
    for ( i = 0; i < p->nSize; i++ )
        p->pArray[i] += Shift;
}
static inline void Vec_IntVars2Lits( Vec_Int_t * p, int Shift, int fCompl )
{
    int i;
    for ( i = 0; i < p->nSize; i++ )
        p->pArray[i] = Abc_Var2Lit( p->pArray[i] + Shift, fCompl );
}
static inline void Vec_IntLits2Vars( Vec_Int_t * p, int Shift )
{
    int i;
    for ( i = 0; i < p->nSize; i++ )
        p->pArray[i] = Abc_Lit2Var( p->pArray[i] ) + Shift;
}
static inline void Vec_IntRemap( Vec_Int_t * p, Vec_Int_t * vMap )
{
    int i;
    for ( i = 0; i < p->nSize; i++ )
        p->pArray[i] = Vec_IntEntry(vMap, p->pArray[i]);
}

static inline void Acb_WinPrint( Acb_Ntk_t * p, Vec_Int_t * vWin, int Pivot, int nDivs )
{
    int i, Node;
    printf( "Window for node %d with %d divisors:\n", Pivot, nDivs );
    Vec_IntForEachEntry( vWin, Node, i )
    {
        if ( i == nDivs )
            printf( " | " );
        if ( Abc_Lit2Var(Node) == Pivot )
            printf( "(%d) ", Pivot );
        else
            printf( "%s%d ", Abc_LitIsCompl(Node) ? "*":"", Abc_Lit2Var(Node) );
    }
    printf( "\n" );
}

static inline void Acb_NtkOrderByRefCount( Acb_Ntk_t * p, Vec_Int_t * vSupp )
{
    int i, j, best_i, nSize = Vec_IntSize(vSupp);
    int * pArray = Vec_IntArray(vSupp);
    for ( i = 0; i < nSize-1; i++ )
    {
        best_i = i;
        for ( j = i+1; j < nSize; j++ )
            if ( Acb_ObjFanoutNum(p, pArray[j]) > Acb_ObjFanoutNum(p, pArray[best_i]) )
                best_i = j;
        ABC_SWAP( int, pArray[i], pArray[best_i] );
    }
}

static inline void Acb_NtkRemapIntoSatVariables( Acb_Ntk_t * p, Vec_Int_t * vSupp )
{
    int k, iFanin;
    Vec_IntForEachEntry( vSupp, iFanin, k )
    {
        assert( Acb_ObjFunc(p, iFanin) >= 0 );
        Vec_IntWriteEntry( vSupp, k, Acb_ObjFunc(p, iFanin) );
    }
}

/**Function*************************************************************

  Synopsis    []

  Description []
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
int Acb_NtkFindSupp1( Acb_Ntk_t * p, int Pivot, sat_solver * pSat, int nVars, int nDivs, Vec_Int_t * vWin, Vec_Int_t * vSupp )
{
    int nSuppNew, status, k, iFanin, * pFanins;
    Vec_IntClear( vSupp );
    Acb_ObjForEachFaninFast( p, Pivot, pFanins, iFanin, k )
        Vec_IntPush( vSupp, iFanin );
    Acb_NtkOrderByRefCount( p, vSupp );
    Acb_NtkRemapIntoSatVariables( p, vSupp );
    Vec_IntVars2Lits( vSupp, 2*nVars, 0 );
    status = sat_solver_solve( pSat, Vec_IntArray(vSupp), Vec_IntLimit(vSupp), 0, 0, 0, 0 );
    if ( status != l_False )
        printf( "Failed internal check at node %d.\n", Pivot );
    assert( status == l_False );
    nSuppNew = sat_solver_minimize_assumptions( pSat, Vec_IntArray(vSupp), Vec_IntSize(vSupp), 0 );
    Vec_IntShrink( vSupp, nSuppNew );
    Vec_IntLits2Vars( vSupp, -2*nVars );
    return Vec_IntSize(vSupp) < Acb_ObjFaninNum(p, Pivot);
}

static int StrCount = 0;

int Acb_NtkFindSupp2( Acb_Ntk_t * p, int Pivot, sat_solver * pSat, int nVars, int nDivs, Vec_Int_t * vWin, Vec_Int_t * vSupp, int nLutSize, int fDelay )
{
    int nSuppNew, status, k, iFanin, * pFanins, k2, iFanin2, * pFanins2;
    Acb_ObjForEachFaninFast( p, Pivot, pFanins, iFanin, k )
        assert( Acb_ObjFunc(p, iFanin) >= 0 && Acb_ObjFunc(p, iFanin) < nDivs );
    if ( fDelay )
    {
        // add non-timing-critical fanins
        int nNonCrits, k2, iFanin2 = 0, * pFanins2;
        assert( Acb_ObjLevelD( p, Pivot ) > 1 );
        Vec_IntClear( vSupp );
        Acb_ObjForEachFaninFast( p, Pivot, pFanins, iFanin, k )
            if ( !Acb_ObjIsDelayCriticalFanin( p, Pivot, iFanin ) )
                Vec_IntPush( vSupp, iFanin );
        nNonCrits = Vec_IntSize(vSupp);
        // add fanins of timing critical fanins
        Acb_ObjForEachFaninFast( p, Pivot, pFanins, iFanin, k )
            if ( Acb_ObjIsDelayCriticalFanin( p, Pivot, iFanin ) )
                Acb_ObjForEachFaninFast( p, iFanin, pFanins2, iFanin2, k2 )
                    Vec_IntPushUnique( vSupp, iFanin2 );
        assert( nNonCrits < Vec_IntSize(vSupp) );
        // sort additional fanins by level
        Vec_IntSelectSortCost( Vec_IntArray(vSupp) + nNonCrits, Vec_IntSize(vSupp) - nNonCrits, &p->vLevelD );
        // translate to SAT vars
        Vec_IntForEachEntry( vSupp, iFanin, k )
        {
            assert( Acb_ObjFunc(p, iFanin) >= 0 );
            Vec_IntWriteEntry( vSupp, k, Acb_ObjFunc(p, iFanin) );
        }
        // solve for these fanins
        Vec_IntVars2Lits( vSupp, 2*nVars, 0 );
        status = sat_solver_solve( pSat, Vec_IntArray(vSupp), Vec_IntLimit(vSupp), 0, 0, 0, 0 );
        if ( status != l_False )
            printf( "Failed internal check at node %d.\n", Pivot );
        assert( status == l_False );
        nSuppNew = sat_solver_minimize_assumptions( pSat, Vec_IntArray(vSupp), Vec_IntSize(vSupp), 0 );
        Vec_IntShrink( vSupp, nSuppNew );
        Vec_IntLits2Vars( vSupp, -2*nVars );
        return Vec_IntSize(vSupp) <= nLutSize;
    }
    // iterate through different fanout free cones
    Acb_ObjForEachFaninFast( p, Pivot, pFanins, iFanin, k )
    {
        if ( !Acb_ObjIsAreaCritical(p, iFanin) )
            continue;
        // collect fanins of the root node
        Vec_IntClear( vSupp );
        Acb_ObjForEachFaninFast( p, Pivot, pFanins2, iFanin2, k2 )
            if ( iFanin != iFanin2 )
                Vec_IntPush( vSupp, iFanin2 );
        // collect fanins of the selected node
        Acb_ObjForEachFaninFast( p, iFanin, pFanins2, iFanin2, k2 )
            Vec_IntPushUnique( vSupp, iFanin2 );
        // sort fanins by level
        Vec_IntSelectSortCost( Vec_IntArray(vSupp), Vec_IntSize(vSupp), &p->vLevelD );
        //Acb_NtkOrderByRefCount( p, vSupp );
        Acb_NtkRemapIntoSatVariables( p, vSupp );
        // solve for these fanins
        Vec_IntVars2Lits( vSupp, 2*nVars, 0 );
        status = sat_solver_solve( pSat, Vec_IntArray(vSupp), Vec_IntLimit(vSupp), 0, 0, 0, 0 );
        if ( status != l_False )
            printf( "Failed internal check at node %d.\n", Pivot );
        assert( status == l_False );
        nSuppNew = sat_solver_minimize_assumptions( pSat, Vec_IntArray(vSupp), Vec_IntSize(vSupp), 0 );
        Vec_IntShrink( vSupp, nSuppNew );
        Vec_IntLits2Vars( vSupp, -2*nVars );
        if ( Vec_IntSize(vSupp) <= nLutSize )
            return 1;
    }
    return 0;
}

int Acb_NtkFindSupp3( Acb_Ntk_t * p, int Pivot, sat_solver * pSat, int nVars, int nDivs, Vec_Int_t * vWin, Vec_Int_t * vSupp, int nLutSize, int fDelay )
{
    int nSuppNew, status, k, iFanin, * pFanins, k2, iFanin2, * pFanins2, k3, iFanin3, * pFanins3, NodeMark;

    if ( fDelay )
        return 0;

    // iterate through pairs of fanins with one fanouts
    Acb_ObjForEachFaninFast( p, Pivot, pFanins, iFanin, k )
    {
        if ( !Acb_ObjIsAreaCritical(p, iFanin) )
            continue;
        Acb_ObjForEachFaninFast( p, Pivot, pFanins2, iFanin2, k2 )
        {
            if ( !Acb_ObjIsAreaCritical(p, iFanin2) || k2 == k )
                continue;
            // iFanin and iFanin2 have 1 fanout
            assert( iFanin != iFanin2 );

            // collect fanins of the root node
            Vec_IntClear( vSupp );
            Acb_ObjForEachFaninFast( p, Pivot, pFanins3, iFanin3, k3 )
                if ( iFanin3 != iFanin && iFanin3 != iFanin2 )
                {
                    assert( Acb_ObjFunc(p, iFanin3) >= 0 );
                    Vec_IntPush( vSupp, Abc_Var2Lit(Acb_ObjFunc(p, iFanin3) + 6*nVars, 0) );
                }
            NodeMark = Vec_IntSize(vSupp);

            // collect fanins of the second node
            Acb_ObjForEachFaninFast( p, iFanin, pFanins3, iFanin3, k3 )
            {
                assert( Acb_ObjFunc(p, iFanin3) >= 0 );
                Vec_IntPush( vSupp, Abc_Var2Lit(Acb_ObjFunc(p, iFanin3) + 6*nVars + nDivs, 0) );
            }
            // collect fanins of the third node
            Acb_ObjForEachFaninFast( p, iFanin2, pFanins3, iFanin3, k3 )
            {
                assert( Acb_ObjFunc(p, iFanin3) >= 0 );
                Vec_IntPushUnique( vSupp, Abc_Var2Lit(Acb_ObjFunc(p, iFanin3) + 6*nVars + nDivs, 0) );
            }
            assert( Vec_IntCheckUniqueSmall(vSupp) );

            // sort fanins by level
            //Vec_IntSelectSortCost( Vec_IntArray(vSupp) + NodeMark, Vec_IntSize(vSupp) - NodeMark, &p->vLevelD );
            // solve for these fanins
            status = sat_solver_solve( pSat, Vec_IntArray(vSupp), Vec_IntLimit(vSupp), 0, 0, 0, 0 );
            if ( status != l_False )
                continue;
            assert( status == l_False );
            nSuppNew = sat_solver_minimize_assumptions( pSat, Vec_IntArray(vSupp), Vec_IntSize(vSupp), 0 );
            Vec_IntShrink( vSupp, nSuppNew );
            Vec_IntLits2Vars( vSupp, -6*nVars );
            Vec_IntSort( vSupp, 1 );
            // count how many belong to H; the rest belong to G
            NodeMark = 0;
            Vec_IntForEachEntry( vSupp, iFanin3, k3 )
                if ( iFanin3 >= nDivs )
                    Vec_IntWriteEntry( vSupp, k3, iFanin3 - nDivs );
                else 
                    NodeMark++;
            if ( NodeMark == 0 )
            {
                //printf( "Obj %d: Special case 1 (vars = %d)\n", Pivot, Vec_IntSize(vSupp) );
                continue;
            }
            assert( NodeMark > 0 );
            if ( Vec_IntSize(vSupp) - NodeMark <= nLutSize )
                return NodeMark;
        }
    }

    // iterate through fanins with one fanout and their fanins with one fanout
    Acb_ObjForEachFaninFast( p, Pivot, pFanins, iFanin, k )
    {
        if ( !Acb_ObjIsAreaCritical(p, iFanin) )
            continue;
        Acb_ObjForEachFaninFast( p, iFanin, pFanins2, iFanin2, k2 )
        {
            if ( !Acb_ObjIsAreaCritical(p, iFanin2) )
                continue;
            // iFanin and iFanin2 have 1 fanout
            assert( iFanin != iFanin2 );

            // collect fanins of the root node
            Vec_IntClear( vSupp );
            Acb_ObjForEachFaninFast( p, Pivot, pFanins3, iFanin3, k3 )
                if ( iFanin3 != iFanin && iFanin3 != iFanin2 )
                    Vec_IntPush( vSupp, Abc_Var2Lit(Acb_ObjFunc(p, iFanin3) + 6*nVars, 0) );
            NodeMark = Vec_IntSize(vSupp);

            // collect fanins of the second node
            Acb_ObjForEachFaninFast( p, iFanin, pFanins3, iFanin3, k3 )
                if ( iFanin3 != iFanin2 )
                    Vec_IntPush( vSupp, Abc_Var2Lit(Acb_ObjFunc(p, iFanin3) + 6*nVars + nDivs, 0) );
            // collect fanins of the third node
            Acb_ObjForEachFaninFast( p, iFanin2, pFanins3, iFanin3, k3 )
            {
                assert( Acb_ObjFunc(p, iFanin3) >= 0 );
                Vec_IntPushUnique( vSupp, Abc_Var2Lit(Acb_ObjFunc(p, iFanin3) + 6*nVars + nDivs, 0) );
            }
            assert( Vec_IntCheckUniqueSmall(vSupp) );

            // sort fanins by level
            //Vec_IntSelectSortCost( Vec_IntArray(vSupp) + NodeMark, Vec_IntSize(vSupp) - NodeMark, &p->vLevelD );
            //Sat_SolverWriteDimacs( pSat, NULL, Vec_IntArray(vSupp), Vec_IntLimit(vSupp), 0 );
            // solve for these fanins
            status = sat_solver_solve( pSat, Vec_IntArray(vSupp), Vec_IntLimit(vSupp), 0, 0, 0, 0 );
            if ( status != l_False )
                printf( "Failed internal check at node %d.\n", Pivot );
            assert( status == l_False );
            nSuppNew = sat_solver_minimize_assumptions( pSat, Vec_IntArray(vSupp), Vec_IntSize(vSupp), 0 );
            Vec_IntShrink( vSupp, nSuppNew );
            Vec_IntLits2Vars( vSupp, -6*nVars );
            Vec_IntSort( vSupp, 1 );
            // count how many belong to H; the rest belong to G
            NodeMark = 0;
            Vec_IntForEachEntry( vSupp, iFanin3, k3 )
                if ( iFanin3 >= nDivs )
                    Vec_IntWriteEntry( vSupp, k3, iFanin3 - nDivs );
                else 
                    NodeMark++;
            if ( NodeMark == 0 )
            {
                //printf( "Obj %d: Special case 2 (vars = %d)\n", Pivot, Vec_IntSize(vSupp) );
                continue;
            }
            assert( NodeMark > 0 );
            if ( Vec_IntSize(vSupp) - NodeMark <= nLutSize )
                return NodeMark;
        }
    }

    return 0;
}

/**Function*************************************************************

  Synopsis    []

  Description []
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
typedef struct Acb_Mfs_t_ Acb_Mfs_t;
struct Acb_Mfs_t_
{
    Acb_Ntk_t *     pNtk;        // network
    Acb_Par_t *     pPars;       // parameters
    sat_solver *    pSat[3];     // SAT solvers
    Vec_Int_t *     vSupp;       // support
    Vec_Int_t *     vFlip;       // support
    Vec_Int_t *     vValues;     // support
    int             nNodes;      // nodes
    int             nWins;       // windows
    int             nWinsAll;    // windows
    int             nDivsAll;    // windows
    int             nChanges[8]; // changes
    int             nOvers;      // overflows
    int             nTwoNodes;   // two nodes
    abctime         timeTotal;
    abctime         timeCnf;
    abctime         timeSol;
    abctime         timeWin;
    abctime         timeSat;
    abctime         timeSatU;
    abctime         timeSatS;
};
Acb_Mfs_t * Acb_MfsStart( Acb_Ntk_t * pNtk, Acb_Par_t * pPars )
{
    Acb_Mfs_t * p = ABC_CALLOC( Acb_Mfs_t, 1 );
    p->pNtk       = pNtk;
    p->pPars      = pPars;
    p->timeTotal  = Abc_Clock();
    p->pSat[0]    = sat_solver_new();
    p->pSat[1]    = sat_solver_new();
    p->pSat[2]    = sat_solver_new();
    p->vSupp      = Vec_IntAlloc(100);
    p->vFlip      = Vec_IntAlloc(100);
    p->vValues    = Vec_IntAlloc(100);
    return p;
}
void Acb_MfsStop( Acb_Mfs_t * p )
{
    Vec_IntFree( p->vFlip );
    Vec_IntFree( p->vSupp );
    Vec_IntFree( p->vValues );
    sat_solver_delete( p->pSat[0] );
    sat_solver_delete( p->pSat[1] );
    sat_solver_delete( p->pSat[2] );
    ABC_FREE( p );
}
static inline int Acb_NtkObjMffcEstimate( Acb_Ntk_t * pNtk, int iObj )
{
    int k, iFanin, * pFanins, Count = 0, iFaninCrit = -1;
    Acb_ObjForEachFaninFast( pNtk, iObj, pFanins, iFanin, k )
        if ( Acb_ObjIsAreaCritical(pNtk, iFanin) )
            iFaninCrit = iFanin, Count++;
    if ( Count != 1 )
        return Count;
    Acb_ObjForEachFaninFast( pNtk, iFaninCrit, pFanins, iFanin, k )
        if ( Acb_ObjIsAreaCritical(pNtk, iFanin) )
            Count++;
    return Count;
}

/**Function*************************************************************

  Synopsis    []

  Description []
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
void Acb_NtkOptNodeAnalyze( Acb_Mfs_t * p, int PivotVar, int nDivs, int nValues, int * pValues, Vec_Int_t * vSupp )
{
    word OnSet[64] = {0};
    word OffSet[64] = {0};
    word Diffs[64] = {0};
    int s, nScope = 1 + 2*nDivs, d, i;
    int f, nFrames = nValues / nScope;
    int start = nDivs < 64 ? 0 : nDivs - 64;
    int stop  = nDivs < 64 ? nDivs : 64;
    assert( nValues % nScope == 0 );
    assert( nFrames <= 16 );
    for ( f = 0; f < nFrames; f++ )
    {
        int * pStart  = pValues + f * nScope;
        int * pOnSet  = pStart + 1 + (pStart[0] ? 0 : nDivs);
        int * pOffSet = pStart + 1 + (pStart[0] ? nDivs : 0);

        printf( "%2d:", f );
        for ( s = start; s < stop; s++ )
            printf( "%d", pOnSet[s] );
        printf( "\n" );

        printf( "%2d:", f );
        for ( s = start; s < stop; s++ )
            printf( "%d", pOffSet[s] );
        printf( "\n" );

        for ( s = start; s < stop; s++ )
        {
            if ( pOnSet[s] )   OnSet[f]  |= (((word)1) << (s-start));
            if ( pOffSet[s] )  OffSet[f] |= (((word)1) << (s-start));
        }
    }
    d = 0;
    for ( f = 0; f < nFrames; f++ )
    for ( s = 0; s < nFrames; s++ )
    {
        for ( i = 0; i < d; i++ )
            if ( Diffs[i] == (OnSet[f] ^ OffSet[s]) )
                break;
        if ( i < d )
            continue;
        if ( d < 64 )
            Diffs[d++] = OnSet[f] ^ OffSet[s];
    }

    printf( "Divisors = %d.  Frames = %d.  Patterns = %d.\n", nDivs, nFrames, d );
    printf( "   " );
    for ( s = start; s < stop; s++ )
        printf( "%d", s / 10 );
    printf( "\n" );
    printf( "   " );
    for ( s = start; s < stop; s++ )
        printf( "%d", s % 10 );
    printf( "\n" );
    printf( "   " );
    for ( s = start; s < stop; s++ )
        printf( "%c", Vec_IntFind(vSupp, s) >= 0 ? 'a' + Vec_IntFind(vSupp, s) : ' ' );
    printf( "\n" );
    for ( s = 0; s < d; s++ )
    {
        printf( "%2d:", s );
        for ( f = 0; f < stop; f++ )
            printf( "%c", ((Diffs[s] >> f) & 1) ? '*' : ' ' );
        printf( "\n" );
    }
}

int Acb_NtkOptNode( Acb_Mfs_t * p, int Pivot )
{
    Cnf_Dat_t * pCnf = NULL; abctime clk;
    Vec_Int_t * vWin = NULL; word uTruth;
    int Result, PivotVar, nDivs = 0, RetValue = 0, c;
    assert( Acb_ObjFanoutNum(p->pNtk, Pivot) > 0 );
    p->nWins++;

    // compute divisors and window for this target node with these taboo nodes
    clk = Abc_Clock();
    vWin = Acb_NtkWindow( p->pNtk, Pivot, p->pPars->nTfiLevMax, p->pPars->nTfoLevMax, p->pPars->nFanoutMax, !p->pPars->fArea, &nDivs );
    p->nWinsAll += Vec_IntSize(vWin);
    p->nDivsAll += nDivs;
    p->timeWin  += Abc_Clock() - clk;
    PivotVar = Vec_IntFind( vWin, Abc_Var2Lit(Pivot, 0) );
    if ( p->pPars->fVerbose )
    printf( "Node %d: Window contains %d objects and %d divisors.  ", Pivot, Vec_IntSize(vWin), nDivs );
//    Acb_WinPrint( p->pNtk, vWin, Pivot, nDivs );
//    Acb_NtkPrintVecWin( p->pNtk, vWin, "Win" );
    if ( Vec_IntSize(vWin) > p->pPars->nWinNodeMax )
    {
        p->nOvers++;
        if ( p->pPars->fVerbose )
            printf( "Too many divisors.\n" );
        goto cleanup;
    }

    // derive CNF 
    clk = Abc_Clock();
    pCnf = Acb_NtkWindow2Cnf( p->pNtk, vWin, Pivot );
    assert( PivotVar == Acb_ObjFunc(p->pNtk, Pivot) );
    Cnf_DataCollectFlipLits( pCnf, PivotVar, p->vFlip );
    p->timeCnf += Abc_Clock() - clk;

    // derive SAT solver
    clk = Abc_Clock();
    Acb_NtkWindow2Solver( p->pSat[0], pCnf, p->vFlip, PivotVar, nDivs, 1 );
    p->timeSol += Abc_Clock() - clk;
    // check constants
    for ( c = 0; c < 2; c++ )
    {
        int Lit = Abc_Var2Lit( PivotVar, c );
        int status = sat_solver_solve( p->pSat[0], &Lit, &Lit + 1, 0, 0, 0, 0 );
        if ( status == l_False )
        {
            p->nChanges[0]++;
            if ( p->pPars->fVerbose )
            printf( "Found constant %d.\n", c );
            Acb_NtkUpdateNode( p->pNtk, Pivot, c ? ~(word)0 : 0, NULL );
            RetValue = 1;
            goto cleanup;
        }
        assert( status == l_True );
    }

    // derive SAT solver
    clk = Abc_Clock();
    Acb_NtkWindow2Solver( p->pSat[1], pCnf, p->vFlip, PivotVar, nDivs, 2 );
    p->timeSol += Abc_Clock() - clk;

    // try to remove useless fanins
    if ( p->pPars->fArea )
    {
        int fEnableProfile = 0;
        if ( fEnableProfile )
        {
            // alloc
            if ( p->pSat[1]->user_values.cap == 0 )
                veci_new(&p->pSat[1]->user_values);
            else
                p->pSat[1]->user_values.size = 0;
            if ( p->pSat[1]->user_vars.cap == 0 )
                veci_new(&p->pSat[1]->user_vars);
            else
                p->pSat[1]->user_vars.size = 0;
            // set variables
            veci_push(&p->pSat[1]->user_vars, PivotVar);
            for ( c = 0; c < nDivs; c++ )
                veci_push(&p->pSat[1]->user_vars, c);
            for ( c = 0; c < nDivs; c++ )
                veci_push(&p->pSat[1]->user_vars, c+pCnf->nVars);
        }

        // perform solving
        clk = Abc_Clock();
        Result = Acb_NtkFindSupp1( p->pNtk, Pivot, p->pSat[1], pCnf->nVars, nDivs, vWin, p->vSupp );
        p->timeSat += Abc_Clock() - clk;
        // undo variables
        p->pSat[1]->user_vars.size = 0;
        if ( Result )
        {
            if ( Vec_IntSize(p->vSupp) == 0 )
                p->nChanges[0]++;
            else
                p->nChanges[1]++;
            assert( Vec_IntSize(p->vSupp) < p->pPars->nLutSize );
            if ( p->pPars->fVerbose )
            printf( "Found %d inputs: ", Vec_IntSize(p->vSupp) );
            uTruth = Acb_ComputeFunction( p->pSat[0], PivotVar, sat_solver_nvars(p->pSat[0])-1, p->vSupp, 0 );
            if ( p->pPars->fVerbose )
            Extra_PrintHex( stdout, (unsigned *)&uTruth, Vec_IntSize(p->vSupp) ); 
            if ( p->pPars->fVerbose )
            printf( "\n" );
            // create support in terms of nodes
            Vec_IntRemap( p->vSupp, vWin );
            Vec_IntLits2Vars( p->vSupp, 0 );
            Acb_NtkUpdateNode( p->pNtk, Pivot, uTruth, p->vSupp );
            RetValue = 1;
            goto cleanup;
        }
        if ( fEnableProfile )
        {
            // analyze the resulting values
            Acb_NtkOptNodeAnalyze( p, PivotVar, nDivs, p->pSat[1]->user_values.size, p->pSat[1]->user_values.ptr, p->vSupp );
            p->pSat[1]->user_values.size = 0;
        }
    }

    if ( Acb_NtkObjMffcEstimate(p->pNtk, Pivot) >= 1 )
    {
        // check for one-node implementation
        clk = Abc_Clock();
        Result = Acb_NtkFindSupp2( p->pNtk, Pivot, p->pSat[1], pCnf->nVars, nDivs, vWin, p->vSupp, p->pPars->nLutSize, !p->pPars->fArea );
        p->timeSat += Abc_Clock() - clk;
        if ( Result )
        {
            p->nChanges[2]++;
            assert( Vec_IntSize(p->vSupp) <= p->pPars->nLutSize );
            if ( p->pPars->fVerbose )
            printf( "Found %d inputs: ", Vec_IntSize(p->vSupp) );
            uTruth = Acb_ComputeFunction( p->pSat[0], PivotVar, sat_solver_nvars(p->pSat[0])-1, p->vSupp, 0 );
            if ( p->pPars->fVerbose )
            Extra_PrintHex( stdout, (unsigned *)&uTruth, Vec_IntSize(p->vSupp) ); 
            if ( p->pPars->fVerbose )
            printf( "\n" );
            // create support in terms of nodes
            Vec_IntRemap( p->vSupp, vWin );
            Vec_IntLits2Vars( p->vSupp, 0 );
            Acb_NtkUpdateNode( p->pNtk, Pivot, uTruth, p->vSupp );
            RetValue = 1;
            goto cleanup;
        }
    }

//#if 0
    if ( p->pPars->fUseAshen && Acb_NtkObjMffcEstimate(p->pNtk, Pivot) >= 2 )// && Pivot != 70 )
    {
        p->nTwoNodes++;
        // derive SAT solver
        clk = Abc_Clock();
        Acb_NtkWindow2Solver( p->pSat[2], pCnf, p->vFlip, PivotVar, nDivs, 6 );
        p->timeSol += Abc_Clock() - clk;

        // check for two-node implementation
        clk = Abc_Clock();
        Result = Acb_NtkFindSupp3( p->pNtk, Pivot, p->pSat[2], pCnf->nVars, nDivs, vWin, p->vSupp, p->pPars->nLutSize, !p->pPars->fArea );
        p->timeSat += Abc_Clock() - clk;
        if ( Result )
        {
            int fVerbose = 1;
            int i, k, Lit, Var, Var2, status, NodeNew, fBecameUnsat = 0, fCompl = 0;
            assert( Result                       <  p->pPars->nLutSize );
            assert( Vec_IntSize(p->vSupp)-Result <= p->pPars->nLutSize );
            if ( fVerbose || p->pPars->fVerbose )
            printf( "Obj %5d: Found %d Hvars and %d Gvars: ", Pivot, Result, Vec_IntSize(p->vSupp)-Result );
            // p->vSupp contains G variables (Vec_IntSize(p->vSupp)-Result) followed by H variables (Result)
            //sat_solver_restart( p->pSat[1] );
            //Acb_NtkWindow2Solver( p->pSat[1], pCnf, p->vFlip, PivotVar, nDivs, 2 );

            // constrain H-variables to be equal
            Vec_IntForEachEntryStart( p->vSupp, Var, i, Vec_IntSize(p->vSupp)-Result ) // H variables
            {
                assert( Var >= 0 && Var < nDivs );
                assert( Var + 2*pCnf->nVars < sat_solver_nvars(p->pSat[1]) );
                Lit = Abc_Var2Lit( Var + 2*pCnf->nVars, 0 ); // HVars are the same
                if ( !sat_solver_addclause( p->pSat[1], &Lit, &Lit + 1 ) )
                { if ( fVerbose || p->pPars->fVerbose ) printf( "Error: SAT solver became UNSAT at a wrong place (place 2).  " ); fBecameUnsat = 1; }
            }
            // find one satisfying assighment
            status = sat_solver_solve( p->pSat[1], NULL, NULL, 0, 0, 0, 0 );
            assert( status == l_True );
            // get assignment of the function
            fCompl = !sat_solver_var_value( p->pSat[1], PivotVar );
            // constrain second set of G-vars to have values equal to the assignment
            Vec_IntForEachEntryStop( p->vSupp, Var, i, Vec_IntSize(p->vSupp)-Result ) // G variables
            {
                // check if this is a C-var
                Vec_IntForEachEntryStart( p->vSupp, Var2, k, Vec_IntSize(p->vSupp)-Result ) // G variables
                    if ( Var == Var2 )
                        break;
                if ( k < Vec_IntSize(p->vSupp) ) // do not constrain a C-var
                {
                    if ( fVerbose || p->pPars->fVerbose )
                    printf( "Found C-var in object %d.  ", Pivot );
                    continue;
                }
                assert( Var >= 0 && Var < nDivs );
                Lit = sat_solver_var_literal( p->pSat[1], Var + pCnf->nVars );
                if ( !sat_solver_addclause( p->pSat[1], &Lit, &Lit + 1 ) )
                { if ( fVerbose || p->pPars->fVerbose ) printf( "Error: SAT solver became UNSAT at a wrong place (place 1).  " ); fBecameUnsat = 1; }
            }
            if ( fBecameUnsat )
            {
                StrCount++;
                if ( fVerbose || p->pPars->fVerbose )
                printf( " Quitting.\n" );
                goto cleanup;
            }
            // consider only G variables
            p->vSupp->nSize -= Result;
            // truth table
            uTruth = Acb_ComputeFunction( p->pSat[1], PivotVar, sat_solver_nvars(p->pSat[1])-1, p->vSupp, fCompl );
            if ( fVerbose || p->pPars->fVerbose )
            Extra_PrintHex( stdout, (unsigned *)&uTruth, Vec_IntSize(p->vSupp) ); 
            if ( uTruth == 0 || ~uTruth == 0 )
            {
                if ( fVerbose || p->pPars->fVerbose )
                printf( " Quitting.\n" );
                goto cleanup;
            }
            p->nChanges[3]++;
            // create new node
            Vec_IntRemap( p->vSupp, vWin );
            Vec_IntLits2Vars( p->vSupp, 0 );
            NodeNew = Acb_NtkCreateNode( p->pNtk, uTruth, p->vSupp );
            Acb_DeriveCnfForWindowOne( p->pNtk, NodeNew );
            Acb_DeriveCnfForNode( p->pNtk, NodeNew, p->pSat[0], sat_solver_nvars(p->pSat[0])-2 );
            p->vSupp->nSize += Result;
            // collect new variables
            Vec_IntForEachEntryStart( p->vSupp, Var, i, Vec_IntSize(p->vSupp)-Result )
                Vec_IntWriteEntry( p->vSupp, i-(Vec_IntSize(p->vSupp)-Result), Var );
            Vec_IntShrink( p->vSupp, Result );
            Vec_IntPush( p->vSupp, sat_solver_nvars(p->pSat[0])-2 );
            // truth table
            uTruth = Acb_ComputeFunction( p->pSat[0], PivotVar, sat_solver_nvars(p->pSat[0])-1, p->vSupp, 0 );
            // create new fanins of the node
            if ( fVerbose || p->pPars->fVerbose )
            printf( "  " );
            if ( fVerbose || p->pPars->fVerbose )
            Extra_PrintHex( stdout, (unsigned *)&uTruth, Vec_IntSize(p->vSupp) ); 
            if ( fVerbose || p->pPars->fVerbose )
            printf( "\n" );
            // create support in terms of nodes
            Vec_IntPop( p->vSupp );
            Vec_IntRemap( p->vSupp, vWin );
            Vec_IntLits2Vars( p->vSupp, 0 );
            Vec_IntPush( p->vSupp, NodeNew );
            Acb_NtkUpdateNode( p->pNtk, Pivot, uTruth, p->vSupp );
            RetValue = 2;
            goto cleanup;
        }
    }
//#endif

    if ( p->pPars->fVerbose )
    printf( "\n" );

cleanup:
    sat_solver_restart( p->pSat[0] );
    sat_solver_restart( p->pSat[1] );
    sat_solver_restart( p->pSat[2] );
    if ( pCnf ) 
    {
        Cnf_DataFree( pCnf );
        Acb_NtkWindowUndo( p->pNtk, vWin );
    }
    Vec_IntFreeP( &vWin );
    return RetValue;
}

/**Function*************************************************************

  Synopsis    []

  Description []
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
void Acb_NtkOpt( Acb_Ntk_t * pNtk, Acb_Par_t * pPars )
{
    Acb_Mfs_t * pMan = Acb_MfsStart( pNtk, pPars );
    if ( pPars->fVerbose )
        printf( "%s-optimization parameters: TfiLev(I) = %d  TfoLev(O) = %d  WinMax(W) = %d  LutSize = %d\n", 
            pMan->pPars->fArea ? "Area" : "Delay", pMan->pPars->nTfiLevMax, pMan->pPars->nTfoLevMax, pMan->pPars->nWinNodeMax, pMan->pPars->nLutSize );
    Acb_NtkCreateFanout( pNtk );  // fanout data structure
    Acb_NtkCleanObjFuncs( pNtk ); // SAT variables
    Acb_NtkCleanObjCnfs( pNtk );  // CNF representations
    if ( pMan->pPars->fArea )
    {
        int n = 0, iObj, RetValue, nNodes = Acb_NtkObjNumMax(pNtk);
        Vec_Bit_t * vVisited = Vec_BitStart( Acb_NtkObjNumMax(pNtk) );
        Acb_NtkUpdateLevelD( pNtk, -1 ); // compute forward logic level
        for ( n = 2; n >= 0; n-- )
            Acb_NtkForEachNode( pNtk, iObj )
                if ( iObj < nNodes && !Vec_BitEntry(vVisited, iObj) && Acb_NtkObjMffcEstimate(pNtk, iObj) >= n )
                {
                    pMan->nNodes++;
                    //if ( iObj != 103 )
                    //    continue;
                    //Acb_NtkOptNode( pMan, iObj );
                    while ( (RetValue = Acb_NtkOptNode(pMan, iObj)) && Acb_ObjFaninNum(pNtk, iObj) );                    
                    Vec_BitWriteEntry( vVisited, iObj, 1 );
                }
        Vec_BitFree( vVisited );
    }
    else
    {
        int Value;
        Acb_NtkUpdateTiming( pNtk, -1 ); // compute delay information
        while ( (Value = (int)Vec_QueTopPriority(pNtk->vQue)) > 0 )
        {
            int iObj = Vec_QuePop(pNtk->vQue);
            if ( !Acb_ObjType(pNtk, iObj) )
                continue;
            //if ( iObj != 103 )
            //    continue;
            //printf( "Trying node %4d (%4d) ", iObj, Value );
            Acb_NtkOptNode( pMan, iObj ); 
        }
    }
    if ( pPars->fVerbose )
    {
        pMan->timeTotal = Abc_Clock() - pMan->timeTotal;
        printf( "Node = %d  Win = %d (Ave = %d)  DivAve = %d   Change = %d  C = %d  N1 = %d  N2 = %d  N3 = %d   Over = %d  Str = %d  2Node = %d.\n", 
            pMan->nNodes, pMan->nWins, pMan->nWinsAll/Abc_MaxInt(1, pMan->nWins), pMan->nDivsAll/Abc_MaxInt(1, pMan->nWins),
            pMan->nChanges[0] + pMan->nChanges[1] + pMan->nChanges[2] + pMan->nChanges[3],
            pMan->nChanges[0], pMan->nChanges[1], pMan->nChanges[2], pMan->nChanges[3], pMan->nOvers, StrCount, pMan->nTwoNodes );
        ABC_PRTP( "Windowing  ", pMan->timeWin,    pMan->timeTotal );
        ABC_PRTP( "CNF compute", pMan->timeCnf,    pMan->timeTotal );
        ABC_PRTP( "Make solver", pMan->timeSol,    pMan->timeTotal );
        ABC_PRTP( "SAT solving", pMan->timeSat,    pMan->timeTotal );
//        ABC_PRTP( "  unsat    ", pMan->timeSatU,   pMan->timeTotal );
//        ABC_PRTP( "  sat      ", pMan->timeSatS,   pMan->timeTotal );
        ABC_PRTP( "TOTAL      ", pMan->timeTotal,  pMan->timeTotal );
        fflush( stdout );
    }
    Acb_MfsStop( pMan );
    StrCount = 0;
}

////////////////////////////////////////////////////////////////////////
///                       END OF FILE                                ///
////////////////////////////////////////////////////////////////////////


ABC_NAMESPACE_IMPL_END