absRefJ.c

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

  FileName    [absRef2.c]

  SystemName  [ABC: Logic synthesis and verification system.]

  PackageName [Abstraction package.]

  Synopsis    [Refinement manager to compute all justifying subsets.]

  Author      [Alan Mishchenko]
  
  Affiliation [UC Berkeley]

  Date        [Ver. 1.0. Started - June 20, 2005.]

  Revision    [$Id: absRef2.c,v 1.00 2005/06/20 00:00:00 alanmi Exp $]

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

#include "abs.h"
#include "absRef2.h"

ABC_NAMESPACE_IMPL_START

/*
    Description of the refinement manager

    This refinement manager should be 
    * started by calling Rf2_ManStart()
       this procedure takes one argument, the user's seq miter as a GIA manager
       - the manager should have only one property output
       - this manager should not change while the refinement manager is alive
       - it cannot be used by external applications for any purpose
       - when the refinement manager stop, GIA manager is the same as at the beginning
       - in the meantime, it will have some data-structures attached to its nodes...
    * stopped by calling Rf2_ManStop()
    * between starting and stopping, refinements are obtained by calling Rf2_ManRefine()

    Procedure Rf2_ManRefine() takes the following arguments:
    * the refinement manager previously started by Rf2_ManStart()
    * counter-example (CEX) obtained by abstracting some logic of GIA
    * mapping (vMap) of inputs of the CEX into the object IDs of the GIA manager
       - only PI, flop outputs, and internal AND nodes can be used in vMap
       - the ordering of objects in vMap is not important
       - however, the index of a non-PI object in vMap is used as its priority
         (the smaller the index, the more likely this non-PI object apears in a refinement)
       - only the logic between PO and the objects listed in vMap is traversed by the manager
         (as a result, GIA can be arbitrarily large, but only objects used in the abstraction
         and the pseudo-PI, that is, objects in the cut, will be visited by the manager)
    * flag fPropFanout defines whether value propagation is done through the fanout
       - it this flag is enabled, theoretically refinement should be better (the result smaller)
    * flag fVerbose may print some statistics

    The refinement manager returns a minimal-size array of integer IDs of GIA objects
    which should be added to the abstraction to possibly prevent the given counter-example
       - only flop output and internal AND nodes from vMap may appear in the resulting array
       - if the resulting array is empty, the CEX is a true CEX 
         (in other words, non-PI objects are not needed to set the PO value to 1)

    Verification of the selected refinement is performed by 
       - initializing all PI objects in vMap to value 0 or 1 they have in the CEX
       - initializing all remaining objects in vMap to value X
       - initializing objects used in the refiment to value 0 or 1 they have in the CEX
       - simulating through as many timeframes as required by the CEX
       - if the PO value in the last frame is 1, the refinement is correct
         (however, the minimality of the refinement is not currently checked)
        
*/

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

typedef struct Rf2_Obj_t_ Rf2_Obj_t; // refinement object
struct Rf2_Obj_t_
{
    unsigned       Value     :  1;  // binary value
    unsigned       fVisit    :  1;  // visited object
    unsigned       fPPi      :  1;  // PPI object
    unsigned       Prio      : 24;  // priority (0 - highest)
};

struct Rf2_Man_t_
{
    // user data
    Gia_Man_t *    pGia;            // working AIG manager (it is completely owned by this package)
    Abc_Cex_t *    pCex;            // counter-example
    Vec_Int_t *    vMap;            // mapping of CEX inputs into objects (PI + PPI, in any order)
    int            fPropFanout;     // propagate fanouts
    int            fVerbose;        // verbose flag
    // traversing data
    Vec_Int_t *    vObjs;           // internal objects used in value propagation
    Vec_Int_t *    vFanins;         // fanins of the PPI nodes
    Vec_Int_t *    pvVecs;          // vectors of integers for each object
    Vec_Vec_t *    vGrp2Ppi;        // for each node, the set of PPIs to include
    int            nMapWords;
    // internal data
    Rf2_Obj_t *    pObjs;           // refinement objects
    int            nObjs;           // the number of used objects
    int            nObjsAlloc;      // the number of allocated objects
    int            nObjsFrame;      // the number of used objects in each frame
    int            nCalls;          // total number of calls
    int            nRefines;        // total refined objects
    // statistics  
    clock_t        timeFwd;         // forward propagation
    clock_t        timeBwd;         // backward propagation
    clock_t        timeVer;         // ternary simulation
    clock_t        timeTotal;       // other time
};

// accessing the refinement object
static inline Rf2_Obj_t * Rf2_ManObj( Rf2_Man_t * p, Gia_Obj_t * pObj, int f )  
{ 
    assert( Gia_ObjIsConst0(pObj) || pObj->Value );
    assert( (int)pObj->Value < p->nObjsFrame );
    assert( f >= 0 && f <= p->pCex->iFrame ); 
    return p->pObjs + f * p->nObjsFrame + pObj->Value;  
}

static inline Vec_Int_t * Rf2_ObjVec( Rf2_Man_t * p, Gia_Obj_t * pObj )  
{
    return p->pvVecs + Gia_ObjId(p->pGia, pObj);
}


static inline unsigned * Rf2_ObjA( Rf2_Man_t * p, Gia_Obj_t * pObj )  
{
    return (unsigned *)Vec_IntArray(Rf2_ObjVec(p, pObj));
}
static inline unsigned * Rf2_ObjN( Rf2_Man_t * p, Gia_Obj_t * pObj )  
{
    return (unsigned *)Vec_IntArray(Rf2_ObjVec(p, pObj)) + p->nMapWords;
}
static inline void Rf2_ObjClear( Rf2_Man_t * p, Gia_Obj_t * pObj )  
{
    Vec_IntFill( Rf2_ObjVec(p, pObj), 2*p->nMapWords, 0 );
}
static inline void Rf2_ObjStart( Rf2_Man_t * p, Gia_Obj_t * pObj, int i )  
{
    Vec_Int_t * vVec = Rf2_ObjVec(p, pObj);
    int w;
    Vec_IntClear( vVec );
    for ( w = 0; w < p->nMapWords; w++ )
        Vec_IntPush( vVec, 0 );
    for ( w = 0; w < p->nMapWords; w++ )
        Vec_IntPush( vVec, ~0 );
    Abc_InfoSetBit( Rf2_ObjA(p, pObj), i );
    Abc_InfoXorBit( Rf2_ObjN(p, pObj), i );
}
static inline void Rf2_ObjCopy( Rf2_Man_t * p, Gia_Obj_t * pObj, Gia_Obj_t * pFanin )  
{
    assert( Vec_IntSize(Rf2_ObjVec(p, pObj)) == 2*p->nMapWords );
    memcpy( Rf2_ObjA(p, pObj), Rf2_ObjA(p, pFanin), sizeof(unsigned) * 2 * p->nMapWords );
}
static inline void Rf2_ObjDeriveAnd( Rf2_Man_t * p, Gia_Obj_t * pObj, int One )  
{
    unsigned * pInfo, * pInfo0, * pInfo1;
    int i;
    assert( Gia_ObjIsAnd(pObj) );
    assert( One == (int)pObj->fMark0 );
    assert( One == (int)(Gia_ObjFanin0(pObj)->fMark0 ^ Gia_ObjFaninC0(pObj)) );
    assert( One == (int)(Gia_ObjFanin1(pObj)->fMark0 ^ Gia_ObjFaninC1(pObj)) );
    assert( Vec_IntSize(Rf2_ObjVec(p, pObj)) == 2*p->nMapWords );

    pInfo  = Rf2_ObjA( p, pObj );
    pInfo0 = Rf2_ObjA( p, Gia_ObjFanin0(pObj) );
    pInfo1 = Rf2_ObjA( p, Gia_ObjFanin1(pObj) );
    for ( i = 0; i < p->nMapWords; i++ )
        pInfo[i] = One ? (pInfo0[i] & pInfo1[i]) : (pInfo0[i] | pInfo1[i]);

    pInfo  = Rf2_ObjN( p, pObj );
    pInfo0 = Rf2_ObjN( p, Gia_ObjFanin0(pObj) );
    pInfo1 = Rf2_ObjN( p, Gia_ObjFanin1(pObj) );
    for ( i = 0; i < p->nMapWords; i++ )
        pInfo[i] = One ? (pInfo0[i] | pInfo1[i]) : (pInfo0[i] & pInfo1[i]);
}
static inline void Rf2_ObjPrint( Rf2_Man_t * p, Gia_Obj_t * pRoot )  
{
    Gia_Obj_t * pObj;
    unsigned * pInfo;
    int i;
    pInfo  = Rf2_ObjA( p, pRoot );
    Gia_ManForEachObjVec( p->vMap, p->pGia, pObj, i )
        if ( !Gia_ObjIsPi(p->pGia, pObj) )
            printf( "%d", Abc_InfoHasBit(pInfo, i) );
    printf( "\n" );
    pInfo  = Rf2_ObjN( p, pRoot );
    Gia_ManForEachObjVec( p->vMap, p->pGia, pObj, i )
        if ( !Gia_ObjIsPi(p->pGia, pObj) )
            printf( "%d", !Abc_InfoHasBit(pInfo, i) );
    printf( "\n" );

}

////////////////////////////////////////////////////////////////////////
///                     FUNCTION DEFINITIONS                         ///
////////////////////////////////////////////////////////////////////////
 
/**Function*************************************************************

  Synopsis    [Creates a new manager.]

  Description []
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
Rf2_Man_t * Rf2_ManStart( Gia_Man_t * pGia )
{
    Rf2_Man_t * p;
    assert( Gia_ManPoNum(pGia) == 1 );
    p = ABC_CALLOC( Rf2_Man_t, 1 );
    p->pGia = pGia;
    p->vObjs = Vec_IntAlloc( 1000 );
    p->vFanins = Vec_IntAlloc( 1000 );
    p->pvVecs = ABC_CALLOC( Vec_Int_t, Gia_ManObjNum(pGia) );
    p->vGrp2Ppi = Vec_VecStart( 100 );
    Gia_ManCleanMark0(pGia);
    Gia_ManCleanMark1(pGia);
    return p;
}
void Rf2_ManStop( Rf2_Man_t * p, int fProfile )
{
    if ( !p ) return;
    // print runtime statistics
    if ( fProfile && p->nCalls )
    {
        double MemGia = sizeof(Gia_Man_t) + sizeof(Gia_Obj_t) * p->pGia->nObjsAlloc + sizeof(int) * p->pGia->nTravIdsAlloc;
        double MemOther = sizeof(Rf2_Man_t) + sizeof(Rf2_Obj_t) * p->nObjsAlloc + sizeof(int) * Vec_IntCap(p->vObjs);
        clock_t timeOther = p->timeTotal - p->timeFwd - p->timeBwd - p->timeVer;
        printf( "Abstraction refinement runtime statistics:\n" );
        ABC_PRTP( "Sensetization", p->timeFwd,   p->timeTotal );
        ABC_PRTP( "Justification", p->timeBwd,   p->timeTotal );
        ABC_PRTP( "Verification ", p->timeVer,   p->timeTotal );
        ABC_PRTP( "Other        ", timeOther,    p->timeTotal );
        ABC_PRTP( "TOTAL        ", p->timeTotal, p->timeTotal );
        printf( "Total calls = %d.  Average refine = %.1f. GIA mem = %.3f MB.  Other mem = %.3f MB.\n", 
            p->nCalls, 1.0*p->nRefines/p->nCalls, MemGia/(1<<20), MemOther/(1<<20) );
    }
    Vec_IntFree( p->vObjs );
    Vec_IntFree( p->vFanins );
    Vec_VecFree( p->vGrp2Ppi );
    ABC_FREE( p->pvVecs );
    ABC_FREE( p );
}
double Rf2_ManMemoryUsage( Rf2_Man_t * p )
{
    return (double)(sizeof(Rf2_Man_t) + sizeof(Vec_Int_t) * Gia_ManObjNum(p->pGia));
}


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

  Synopsis    [Collect internal objects to be used in value propagation.]

  Description [Resulting array vObjs contains RO, AND, PO/RI in a topo order.]
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
void Rf2_ManCollect_rec( Gia_Man_t * p, Gia_Obj_t * pObj, Vec_Int_t * vObjs )
{
    if ( Gia_ObjIsTravIdCurrent(p, pObj) )
        return;
    Gia_ObjSetTravIdCurrent(p, pObj);
    if ( Gia_ObjIsCo(pObj) )
        Rf2_ManCollect_rec( p, Gia_ObjFanin0(pObj), vObjs );
    else if ( Gia_ObjIsAnd(pObj) )
    {
        Rf2_ManCollect_rec( p, Gia_ObjFanin0(pObj), vObjs );
        Rf2_ManCollect_rec( p, Gia_ObjFanin1(pObj), vObjs );
    }
    else if ( !Gia_ObjIsRo(p, pObj) )
        assert( 0 );
    Vec_IntPush( vObjs, Gia_ObjId(p, pObj) );
}
void Rf2_ManCollect( Rf2_Man_t * p )
{
    Gia_Obj_t * pObj = NULL;
    int i;
    // mark const/PIs/PPIs
    Gia_ManIncrementTravId( p->pGia );
    Gia_ObjSetTravIdCurrent( p->pGia, Gia_ManConst0(p->pGia) );
    Gia_ManForEachObjVec( p->vMap, p->pGia, pObj, i )
    {
        assert( Gia_ObjIsCi(pObj) || Gia_ObjIsAnd(pObj) );
        Gia_ObjSetTravIdCurrent( p->pGia, pObj );
    }
    // collect objects
    Vec_IntClear( p->vObjs );
    Rf2_ManCollect_rec( p->pGia, Gia_ManPo(p->pGia, 0), p->vObjs );
    Gia_ManForEachObjVec( p->vObjs, p->pGia, pObj, i )
        if ( Gia_ObjIsRo(p->pGia, pObj) )
            Rf2_ManCollect_rec( p->pGia, Gia_ObjRoToRi(p->pGia, pObj), p->vObjs );
    // the last object should be a CO
    assert( Gia_ObjIsCo(pObj) );
}

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

  Synopsis    [Performs sensitization analysis.]

  Description []
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
int Rf2_ManSensitize( Rf2_Man_t * p )
{
    Rf2_Obj_t * pRnm, * pRnm0, * pRnm1;
    Gia_Obj_t * pObj;
    int f, i, iBit = p->pCex->nRegs;
    // const0 is initialized automatically in all timeframes
    for ( f = 0; f <= p->pCex->iFrame; f++, iBit += p->pCex->nPis )
    {
        Gia_ManForEachObjVec( p->vMap, p->pGia, pObj, i )
        {
            assert( Gia_ObjIsCi(pObj) || Gia_ObjIsAnd(pObj) );
            pRnm = Rf2_ManObj( p, pObj, f );
            pRnm->Value = Abc_InfoHasBit( p->pCex->pData, iBit + i );
            if ( !Gia_ObjIsPi(p->pGia, pObj) ) // this is PPI
            {
                assert( pObj->Value > 0 );
                pRnm->Prio = pObj->Value;
                pRnm->fPPi = 1;
            }
        }
        Gia_ManForEachObjVec( p->vObjs, p->pGia, pObj, i )
        {
            assert( Gia_ObjIsRo(p->pGia, pObj) || Gia_ObjIsAnd(pObj) || Gia_ObjIsCo(pObj) );
            pRnm = Rf2_ManObj( p, pObj, f );
            assert( !pRnm->fPPi );
            if ( Gia_ObjIsRo(p->pGia, pObj) )
            {
                if ( f == 0 )
                    continue;
                pRnm0 = Rf2_ManObj( p, Gia_ObjRoToRi(p->pGia, pObj), f-1 );
                pRnm->Value = pRnm0->Value;
                pRnm->Prio  = pRnm0->Prio;
                continue;
            }
            if ( Gia_ObjIsCo(pObj) )
            {
                pRnm0 = Rf2_ManObj( p, Gia_ObjFanin0(pObj), f );
                pRnm->Value = (pRnm0->Value ^ Gia_ObjFaninC0(pObj));
                pRnm->Prio  = pRnm0->Prio;
                continue;
            }
            assert( Gia_ObjIsAnd(pObj) );
            pRnm0 = Rf2_ManObj( p, Gia_ObjFanin0(pObj), f );
            pRnm1 = Rf2_ManObj( p, Gia_ObjFanin1(pObj), f );
            pRnm->Value = (pRnm0->Value ^ Gia_ObjFaninC0(pObj)) & (pRnm1->Value ^ Gia_ObjFaninC1(pObj));
            if ( pRnm->Value == 1 )
                pRnm->Prio  = Abc_MaxInt( pRnm0->Prio, pRnm1->Prio );
            else if ( (pRnm0->Value ^ Gia_ObjFaninC0(pObj)) == 0 && (pRnm1->Value ^ Gia_ObjFaninC1(pObj)) == 0 )
                pRnm->Prio  = Abc_MinInt( pRnm0->Prio, pRnm1->Prio ); // choice
            else if ( (pRnm0->Value ^ Gia_ObjFaninC0(pObj)) == 0 )
                pRnm->Prio  = pRnm0->Prio;
            else 
                pRnm->Prio  = pRnm1->Prio;
        }
    }
    assert( iBit == p->pCex->nBits );
    pRnm = Rf2_ManObj( p, Gia_ManPo(p->pGia, 0), p->pCex->iFrame );
    if ( pRnm->Value != 1 )
        printf( "Output value is incorrect.\n" );
    return pRnm->Prio;
}



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

  Synopsis    [Performs refinement.]

  Description []
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
void Rf2_ManVerifyUsingTerSim( Gia_Man_t * p, Abc_Cex_t * pCex, Vec_Int_t * vMap, Vec_Int_t * vObjs, Vec_Int_t * vRes )
{
    Gia_Obj_t * pObj;
    int i, f, iBit = pCex->nRegs;
    Gia_ObjTerSimSet0( Gia_ManConst0(p) );
    for ( f = 0; f <= pCex->iFrame; f++, iBit += pCex->nPis )
    {
        Gia_ManForEachObjVec( vMap, p, pObj, i )
        {
            pObj->Value = Abc_InfoHasBit( pCex->pData, iBit + i );
            if ( !Gia_ObjIsPi(p, pObj) )
                Gia_ObjTerSimSetX( pObj );
            else if ( pObj->Value )
                Gia_ObjTerSimSet1( pObj );
            else
                Gia_ObjTerSimSet0( pObj );
        }
        Gia_ManForEachObjVec( vRes, p, pObj, i ) // vRes is subset of vMap
        {
            if ( pObj->Value )
                Gia_ObjTerSimSet1( pObj );
            else
                Gia_ObjTerSimSet0( pObj );
        }
        Gia_ManForEachObjVec( vObjs, p, pObj, i )
        {
            if ( Gia_ObjIsCo(pObj) )
                Gia_ObjTerSimCo( pObj );
            else if ( Gia_ObjIsAnd(pObj) )
                Gia_ObjTerSimAnd( pObj );
            else if ( f == 0 )
                Gia_ObjTerSimSet0( pObj );
            else
                Gia_ObjTerSimRo( p, pObj );
        }
    }
    Gia_ManForEachObjVec( vMap, p, pObj, i )
        pObj->Value = 0;
    pObj = Gia_ManPo( p, 0 );
    if ( !Gia_ObjTerSimGet1(pObj) )
        Abc_Print( 1, "\nRefinement verification has failed!!!\n" );
}

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

  Synopsis    [Computes the refinement for a given counter-example.]

  Description []
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
void Rf2_ManGatherFanins_rec( Rf2_Man_t * p, Gia_Obj_t * pObj, Vec_Int_t * vFanins, int Depth, int RootId, int fFirst )
{
    if ( Gia_ObjIsTravIdCurrent(p->pGia, pObj) )
        return;
    Gia_ObjSetTravIdCurrent(p->pGia, pObj);
    if ( pObj->fPhase && !fFirst )
    {
        Vec_Int_t * vVec = Rf2_ObjVec( p, pObj );
//        if ( Vec_IntEntry( vVec, 0 ) == 0 )
//            return;
        if ( Vec_IntSize(vVec) == 0 )
            Vec_IntPush( vFanins, Gia_ObjId(p->pGia, pObj) );
        Vec_IntPushUnique( vVec, RootId );
        if ( Depth == 0 )
            return;
    }
    if ( Gia_ObjIsPi(p->pGia, pObj) || Gia_ObjIsConst0(pObj) )
        return;
    if ( Gia_ObjIsRo(p->pGia, pObj) )
    {
        assert( pObj->fPhase );
        pObj = Gia_ObjRoToRi(p->pGia, pObj);
        Rf2_ManGatherFanins_rec( p, Gia_ObjFanin0(pObj), vFanins, Depth - 1, RootId, 0 );
    }
    else if ( Gia_ObjIsAnd(pObj) )
    {
        Rf2_ManGatherFanins_rec( p, Gia_ObjFanin0(pObj), vFanins, Depth - pObj->fPhase, RootId, 0 );
        Rf2_ManGatherFanins_rec( p, Gia_ObjFanin1(pObj), vFanins, Depth - pObj->fPhase, RootId, 0 );
    }
    else assert( 0 );
}
void Rf2_ManGatherFanins( Rf2_Man_t * p, int Depth )
{
    Vec_Int_t * vUsed;
    Vec_Int_t * vVec;
    Gia_Obj_t * pObj;
    int i, k, Entry;
    // mark PPIs
    Gia_ManForEachObjVec( p->vMap, p->pGia, pObj, i )
    {
        vVec = Rf2_ObjVec( p, pObj );
        assert( Vec_IntSize(vVec) == 0 );
        Vec_IntPush( vVec, 0 );
    }
    // collect internal
    Vec_IntClear( p->vFanins );
    Gia_ManForEachObjVec( p->vMap, p->pGia, pObj, i )
    {
        if ( Gia_ObjIsPi(p->pGia, pObj) )
            continue;
        Gia_ManIncrementTravId( p->pGia );
        Rf2_ManGatherFanins_rec( p, pObj, p->vFanins, Depth, i, 1 );
    }

    vUsed = Vec_IntStart( Vec_IntSize(p->vMap) );

    // evaluate collected
    printf( "\nMap (%d): ", Vec_IntSize(p->vMap) );
    Gia_ManForEachObjVec( p->vMap, p->pGia, pObj, i )
    {
        vVec = Rf2_ObjVec( p, pObj );
        if ( Vec_IntSize(vVec) > 1 )
            printf( "%d=%d ", i, Vec_IntSize(vVec) - 1 );
        Vec_IntForEachEntryStart( vVec, Entry, k, 1 )
            Vec_IntAddToEntry( vUsed, Entry, 1 );
        Vec_IntClear( vVec );
    }
    printf( "\n" );
    // evaluate internal
    printf( "Int (%d): ", Vec_IntSize(p->vFanins) );
    Gia_ManForEachObjVec( p->vFanins, p->pGia, pObj, i )
    {
        vVec = Rf2_ObjVec( p, pObj );
        if ( Vec_IntSize(vVec) > 1 )
            printf( "%d=%d ", i, Vec_IntSize(vVec) );
        if ( Vec_IntSize(vVec) > 1 )
            Vec_IntForEachEntry( vVec, Entry, k )
                Vec_IntAddToEntry( vUsed, Entry, 1 );
        Vec_IntClear( vVec );
    }
    printf( "\n" );
    // evaluate PPIs    
    Vec_IntForEachEntry( vUsed, Entry, k )
        printf( "%d ", Entry );
    printf( "\n" );

    Vec_IntFree( vUsed );
}


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

  Synopsis    [Sort, make dup- and containment-free, and filter.]

  Description []
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
static inline int Rf2_ManCountPpis( Rf2_Man_t * p )
{
    Gia_Obj_t * pObj;
    int i, Counter = 0;
    Gia_ManForEachObjVec( p->vMap, p->pGia, pObj, i )
        if ( !Gia_ObjIsPi(p->pGia, pObj) ) // this is PPI
            Counter++;
    return Counter;
}

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

  Synopsis    [Sort, make dup- and containment-free, and filter.]

  Description []
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
static inline void Rf2_ManPrintVector( Vec_Int_t * p, int Num )
{
    int i, k, Entry;
    Vec_IntForEachEntry( p, Entry, i )
    {
        for ( k = 0; k < Num; k++ )
            printf( "%c", '0' + ((Entry>>k) & 1) );
        printf( "\n" );
    }
}

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

  Synopsis    [Sort, make dup- and containment-free, and filter.]

  Description []
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
static inline void Rf2_ManProcessVector( Vec_Int_t * p, int Limit )
{
//    int Start = Vec_IntSize(p);
    int Start = 0;
    int i, j, k, Entry, Entry2;
//    printf( "%d", Vec_IntSize(p) );
    if ( Start > 5 )
    {
        printf( "Before: \n" );
        Rf2_ManPrintVector( p, 31 );
    }

    k = 0;
    Vec_IntForEachEntry( p, Entry, i )
        if ( Gia_WordCountOnes((unsigned)Entry) <= Limit )
            Vec_IntWriteEntry( p, k++, Entry );
    Vec_IntShrink( p, k );            
    Vec_IntSort( p, 0 );
    k = 0;
    Vec_IntForEachEntry( p, Entry, i )
    {
        Vec_IntForEachEntryStop( p, Entry2, j, i )
            if ( (Entry2 & Entry) == Entry2 ) // Entry2 is a subset of Entry
                break; 
        if ( j == i ) // Entry is not contained in any Entry2
            Vec_IntWriteEntry( p, k++, Entry );
    }
    Vec_IntShrink( p, k );            
//    printf( "->%d ", Vec_IntSize(p) );
    if ( Start > 5 )
    {
        printf( "After: \n" );
        Rf2_ManPrintVector( p, 31 );
        k = 0;
    }
}

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

  Synopsis    [Assigns a unique justifification ID for each PPI.]

  Description []
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
int Rf2_ManAssignJustIds( Rf2_Man_t * p )
{
    Gia_Obj_t * pObj;
    int nPpis = Rf2_ManCountPpis( p );
    int nGroupSize = (nPpis / 30) + (nPpis % 30 > 0);
    int i, k = 0;
    Vec_VecClear( p->vGrp2Ppi );
    Gia_ManForEachObjVec( p->vMap, p->pGia, pObj, i )
        if ( !Gia_ObjIsPi(p->pGia, pObj) ) // this is PPI
            Vec_VecPushInt( p->vGrp2Ppi, (k++ / nGroupSize), i );
    printf( "Considering %d PPIs combined into %d groups of size %d.\n", k, (k-1)/nGroupSize+1, nGroupSize );
    return (k-1)/nGroupSize+1;
}

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

  Synopsis    [Sort, make dup- and containment-free, and filter.]

  Description []
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
static inline void Rf2_ManPrintVectorSpecial( Rf2_Man_t * p, Vec_Int_t * vVec )
{
    Gia_Obj_t * pObj;
    int nPpis = Rf2_ManCountPpis( p );
    int nGroupSize = (nPpis / 30) + (nPpis % 30 > 0);
    int s, i, k, Entry, Counter;

    Vec_IntForEachEntry( vVec, Entry, s )
    {
        k = 0;
        Counter = 0;
        Gia_ManForEachObjVec( p->vMap, p->pGia, pObj, i )
        {
            if ( !Gia_ObjIsPi(p->pGia, pObj) ) // this is PPI
            {
                if ( (Entry >> (k++ / nGroupSize)) & 1 )
                    printf( "1" ), Counter++;
                else
                    printf( "0" );
            }
            else
                printf( "-" );
        }
        printf( " %3d \n", Counter );
    }
}

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

  Synopsis    [Performs justification propagation.]

  Description []
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
Vec_Int_t * Rf2_ManPropagate( Rf2_Man_t * p, int Limit )
{
    Vec_Int_t * vVec, * vVec0, * vVec1;
    Gia_Obj_t * pObj;
    int f, i, k, j, Entry, Entry2, iBit = p->pCex->nRegs;
    // init constant
    pObj = Gia_ManConst0(p->pGia);
    pObj->fMark0 = 0;
    Vec_IntFill( Rf2_ObjVec(p, pObj), 1, 0 );
    // iterate through the timeframes
    for ( f = 0; f <= p->pCex->iFrame; f++, iBit += p->pCex->nPis )
    {
        // initialize frontier values and init justification sets
        Gia_ManForEachObjVec( p->vMap, p->pGia, pObj, i )
        {
            assert( Gia_ObjIsCi(pObj) || Gia_ObjIsAnd(pObj) );
            pObj->fMark0 = Abc_InfoHasBit( p->pCex->pData, iBit + i );
            Vec_IntFill( Rf2_ObjVec(p, pObj), 1, 0 );
        }
        // assign justification sets for PPis
        Vec_VecForEachLevelInt( p->vGrp2Ppi, vVec, i )
            Vec_IntForEachEntry( vVec, Entry, k )
            {
                assert( i < 31 );
                pObj = Gia_ManObj( p->pGia, Vec_IntEntry(p->vMap, Entry) );
                assert( Vec_IntSize(Rf2_ObjVec(p, pObj)) == 1 );
                Vec_IntAddToEntry( Rf2_ObjVec(p, pObj), 0, (1 << i) );
            }
        // propagate internal nodes
        Gia_ManForEachObjVec( p->vObjs, p->pGia, pObj, i )
        {
            pObj->fMark0 = 0;
            vVec = Rf2_ObjVec(p, pObj);
            Vec_IntClear( vVec );
            if ( Gia_ObjIsRo(p->pGia, pObj) )
            {
                if ( f == 0 )
                {
                    Vec_IntPush( vVec, 0 );
                    continue;
                }
                pObj->fMark0 = Gia_ObjRoToRi(p->pGia, pObj)->fMark0;
                vVec0 = Rf2_ObjVec( p, Gia_ObjRoToRi(p->pGia, pObj) );
                Vec_IntAppend( vVec, vVec0 );
                continue;
            }
            if ( Gia_ObjIsCo(pObj) )
            {
                pObj->fMark0 = (Gia_ObjFanin0(pObj)->fMark0 ^ Gia_ObjFaninC0(pObj));
                vVec0 = Rf2_ObjVec( p, Gia_ObjFanin0(pObj) );
                Vec_IntAppend( vVec, vVec0 );
                continue;
            }
            assert( Gia_ObjIsAnd(pObj) );
            vVec0 = Rf2_ObjVec(p, Gia_ObjFanin0(pObj));
            vVec1 = Rf2_ObjVec(p, Gia_ObjFanin1(pObj));
            pObj->fMark0 = (Gia_ObjFanin0(pObj)->fMark0 ^ Gia_ObjFaninC0(pObj)) & (Gia_ObjFanin1(pObj)->fMark0 ^ Gia_ObjFaninC1(pObj));
            if ( pObj->fMark0 == 1 )
            {
                Vec_IntForEachEntry( vVec0, Entry, k )
                    Vec_IntForEachEntry( vVec1, Entry2, j )
                        Vec_IntPush( vVec, Entry | Entry2 );
                Rf2_ManProcessVector( vVec, Limit );
            }
            else if ( (Gia_ObjFanin0(pObj)->fMark0 ^ Gia_ObjFaninC0(pObj)) == 0 && (Gia_ObjFanin1(pObj)->fMark0 ^ Gia_ObjFaninC1(pObj)) == 0 )
            {
                Vec_IntAppend( vVec, vVec0 );
                Vec_IntAppend( vVec, vVec1 );
                Rf2_ManProcessVector( vVec, Limit );
            }
            else if ( (Gia_ObjFanin0(pObj)->fMark0 ^ Gia_ObjFaninC0(pObj)) == 0 )
                Vec_IntAppend( vVec, vVec0 );
            else 
                Vec_IntAppend( vVec, vVec1 );
        }
    }
    assert( iBit == p->pCex->nBits );
    if ( Gia_ManPo(p->pGia, 0)->fMark0 != 1 )
        printf( "Output value is incorrect.\n" );
    return Rf2_ObjVec(p, Gia_ManPo(p->pGia, 0));
}

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

  Synopsis    [Performs justification propagation.]

  Description []
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
void Rf2_ManBounds( Rf2_Man_t * p )
{
    Gia_Obj_t * pObj;
    int f, i, iBit = p->pCex->nRegs;
    // init constant
    pObj = Gia_ManConst0(p->pGia);
    pObj->fMark0 = 0;
    Rf2_ObjStart( p, pObj, Vec_IntSize(p->vMap) + Vec_IntSize(p->vObjs) );
    // iterate through the timeframes
    for ( f = 0; f <= p->pCex->iFrame; f++, iBit += p->pCex->nPis )
    {
        // initialize frontier values and init justification sets
        Gia_ManForEachObjVec( p->vMap, p->pGia, pObj, i )
        {
            assert( Gia_ObjIsCi(pObj) || Gia_ObjIsAnd(pObj) );
            pObj->fMark0 = Abc_InfoHasBit( p->pCex->pData, iBit + i );
            Rf2_ObjStart( p, pObj, i );
        }
        // propagate internal nodes
        Gia_ManForEachObjVec( p->vObjs, p->pGia, pObj, i )
        {
            pObj->fMark0 = 0;
            Rf2_ObjClear( p, pObj );
            if ( Gia_ObjIsRo(p->pGia, pObj) )
            {
                if ( f == 0 )
                {
                    Rf2_ObjStart( p, pObj, Vec_IntSize(p->vMap) + i );
                    continue;
                }
                pObj->fMark0 = Gia_ObjRoToRi(p->pGia, pObj)->fMark0;
                Rf2_ObjCopy( p, pObj, Gia_ObjRoToRi(p->pGia, pObj) );
                continue;
            }
            if ( Gia_ObjIsCo(pObj) )
            {
                pObj->fMark0 = (Gia_ObjFanin0(pObj)->fMark0 ^ Gia_ObjFaninC0(pObj));
                Rf2_ObjCopy( p, pObj, Gia_ObjFanin0(pObj) );
                continue;
            }
            assert( Gia_ObjIsAnd(pObj) );
            pObj->fMark0 = (Gia_ObjFanin0(pObj)->fMark0 ^ Gia_ObjFaninC0(pObj)) & (Gia_ObjFanin1(pObj)->fMark0 ^ Gia_ObjFaninC1(pObj));
            if ( pObj->fMark0 == 1 )
                Rf2_ObjDeriveAnd( p, pObj, 1 );
            else if ( (Gia_ObjFanin0(pObj)->fMark0 ^ Gia_ObjFaninC0(pObj)) == 0 && (Gia_ObjFanin1(pObj)->fMark0 ^ Gia_ObjFaninC1(pObj)) == 0 )
                Rf2_ObjDeriveAnd( p, pObj, 0 );
            else if ( (Gia_ObjFanin0(pObj)->fMark0 ^ Gia_ObjFaninC0(pObj)) == 0 )
                Rf2_ObjCopy( p, pObj, Gia_ObjFanin0(pObj) );
            else 
                Rf2_ObjCopy( p, pObj, Gia_ObjFanin1(pObj) );
        }
    }
    assert( iBit == p->pCex->nBits );
    if ( Gia_ManPo(p->pGia, 0)->fMark0 != 1 )
        printf( "Output value is incorrect.\n" );

    printf( "Bounds: \n" );
    Rf2_ObjPrint( p, Gia_ManPo(p->pGia, 0) );
}

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

  Synopsis    [Computes the refinement for a given counter-example.]

  Description []
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
Vec_Int_t * Rf2_ManRefine( Rf2_Man_t * p, Abc_Cex_t * pCex, Vec_Int_t * vMap, int fPropFanout, int fVerbose )
{
    Vec_Int_t * vJusts;
//    Vec_Int_t * vSelected = Vec_IntAlloc( 100 );
    Vec_Int_t * vSelected = NULL;
    clock_t clk, clk2 = clock();
    int nGroups;
    p->nCalls++;
    // initialize
    p->pCex = pCex;
    p->vMap = vMap;
    p->fPropFanout = fPropFanout;
    p->fVerbose    = fVerbose;
    // collects used objects
    Rf2_ManCollect( p );
    // collect reconvergence points
//    Rf2_ManGatherFanins( p, 2 );
    // propagate justification IDs
    nGroups = Rf2_ManAssignJustIds( p );
    vJusts = Rf2_ManPropagate( p, 32 );

//    printf( "\n" );
//    Rf2_ManPrintVector( vJusts, nGroups );
    Rf2_ManPrintVectorSpecial( p, vJusts );
    if ( Vec_IntSize(vJusts) == 0 )
    {
        printf( "Empty set of justifying subsets.\n" );
        return NULL;
    }

//    p->nMapWords = Abc_BitWordNum( Vec_IntSize(p->vMap) + Vec_IntSize(p->vObjs) + 1 ); // Map + Flops + Const
//    Rf2_ManBounds( p );

    // select the result
//    Abc_PrintTime( 1, "Time", clock() - clk2 );

    // verify (empty) refinement
    clk = clock();
//    Rf2_ManVerifyUsingTerSim( p->pGia, p->pCex, p->vMap, p->vObjs, vSelected );
//    Vec_IntUniqify( vSelected );
//    Vec_IntReverseOrder( vSelected );
    p->timeVer += clock() - clk;
    p->timeTotal += clock() - clk2;
//    p->nRefines += Vec_IntSize(vSelected);
    return vSelected;
}

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


ABC_NAMESPACE_IMPL_END