pdrSat.c

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

  FileName    [pdrSat.c]

  SystemName  [ABC: Logic synthesis and verification system.]

  PackageName [Property driven reachability.]

  Synopsis    [SAT solver procedures.]

  Author      [Alan Mishchenko]
  
  Affiliation [UC Berkeley]

  Date        [Ver. 1.0. Started - November 20, 2010.]

  Revision    [$Id: pdrSat.c,v 1.00 2010/11/20 00:00:00 alanmi Exp $]

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

#include "pdrInt.h"

ABC_NAMESPACE_IMPL_START


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

  Synopsis    [Creates new SAT solver.]

  Description []
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
sat_solver * Pdr_ManCreateSolver( Pdr_Man_t * p, int k )
{
    sat_solver * pSat;
    Aig_Obj_t * pObj;
    int i;
    assert( Vec_PtrSize(p->vSolvers) == k );
    assert( Vec_VecSize(p->vClauses) == k );
    assert( Vec_IntSize(p->vActVars) == k );
    // create new solver
    pSat = sat_solver_new();
    pSat = Pdr_ManNewSolver( pSat, p, k, (int)(k == 0) );
    Vec_PtrPush( p->vSolvers, pSat );
    Vec_VecExpand( p->vClauses, k );
    Vec_IntPush( p->vActVars, 0 );
    // add property cone
//    Pdr_ObjSatVar( p, k, Aig_ManCo(p->pAig, (p->pPars->iOutput==-1)?0:p->pPars->iOutput ) );
    Saig_ManForEachPo( p->pAig, pObj, i )
        Pdr_ObjSatVar( p, k, pObj );
    return pSat;
}

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

  Synopsis    [Returns old or restarted solver.]

  Description []
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
sat_solver * Pdr_ManFetchSolver( Pdr_Man_t * p, int k )
{
    sat_solver * pSat;
    Vec_Ptr_t * vArrayK;
    Pdr_Set_t * pCube;
    int i, j;
    pSat = Pdr_ManSolver(p, k);
    if ( Vec_IntEntry(p->vActVars, k) < p->pPars->nRecycle )
        return pSat;
    assert( k < Vec_PtrSize(p->vSolvers) - 1 );
    p->nStarts++;
//    sat_solver_delete( pSat );
//    pSat = sat_solver_new();
    sat_solver_rollback( pSat );
    // create new SAT solver
    pSat = Pdr_ManNewSolver( pSat, p, k, (int)(k == 0) );
    // write new SAT solver
    Vec_PtrWriteEntry( p->vSolvers, k, pSat );
    Vec_IntWriteEntry( p->vActVars, k, 0 );
    // set the property output
    Pdr_ManSetPropertyOutput( p, k );
    // add the clauses
    Vec_VecForEachLevelStart( p->vClauses, vArrayK, i, k )
        Vec_PtrForEachEntry( Pdr_Set_t *, vArrayK, pCube, j )
            Pdr_ManSolverAddClause( p, k, pCube );
    return pSat;
}

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

  Synopsis    [Converts SAT variables into register IDs.]

  Description []
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
Vec_Int_t * Pdr_ManLitsToCube( Pdr_Man_t * p, int k, int * pArray, int nArray )
{
    int i, RegId;
    Vec_IntClear( p->vLits );
    for ( i = 0; i < nArray; i++ )
    {
        RegId = Pdr_ObjRegNum( p, k, lit_var(pArray[i]) );
        if ( RegId == -1 )
            continue;
        assert( RegId >= 0 && RegId < Aig_ManRegNum(p->pAig) );
        Vec_IntPush( p->vLits, toLitCond(RegId, !lit_sign(pArray[i])) );
    }
    assert( Vec_IntSize(p->vLits) >= 0 && Vec_IntSize(p->vLits) <= nArray );
    return p->vLits;
}

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

  Synopsis    [Converts the cube in terms of RO numbers into array of CNF literals.]

  Description []
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
Vec_Int_t * Pdr_ManCubeToLits( Pdr_Man_t * p, int k, Pdr_Set_t * pCube, int fCompl, int fNext )
{
    Aig_Obj_t * pObj;
    int i, iVar, iVarMax = 0;
    clock_t clk = clock();
    Vec_IntClear( p->vLits );
    for ( i = 0; i < pCube->nLits; i++ )
    {
        if ( pCube->Lits[i] == -1 )
            continue;
        if ( fNext )
            pObj = Saig_ManLi( p->pAig, lit_var(pCube->Lits[i]) );
        else
            pObj = Saig_ManLo( p->pAig, lit_var(pCube->Lits[i]) );
        iVar = Pdr_ObjSatVar( p, k, pObj ); assert( iVar >= 0 );
        iVarMax = Abc_MaxInt( iVarMax, iVar );
        Vec_IntPush( p->vLits, toLitCond( iVar, fCompl ^ lit_sign(pCube->Lits[i]) ) );
    }
//    sat_solver_setnvars( Pdr_ManSolver(p, k), iVarMax + 1 );
    p->tCnf += clock() - clk;
    return p->vLits;
}

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

  Synopsis    [Sets the property output to 0 (sat) forever.]

  Description []
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
void Pdr_ManSetPropertyOutput( Pdr_Man_t * p, int k )
{
    sat_solver * pSat;
    Aig_Obj_t * pObj;
    int Lit, RetValue, i;
    pSat = Pdr_ManSolver(p, k);
    Saig_ManForEachPo( p->pAig, pObj, i )
    {
        // skip solved outputs
        if ( p->vCexes && Vec_PtrEntry(p->vCexes, i) )
            continue;
        Lit = toLitCond( Pdr_ObjSatVar(p, k, pObj), 1 ); // neg literal
        RetValue = sat_solver_addclause( pSat, &Lit, &Lit + 1 );
        assert( RetValue == 1 );
    }
    sat_solver_compress( pSat );
}

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

  Synopsis    [Adds one clause in terms of ROs to the k-th SAT solver.]

  Description []
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
void Pdr_ManSolverAddClause( Pdr_Man_t * p, int k, Pdr_Set_t * pCube )
{
    sat_solver * pSat;
    Vec_Int_t * vLits;
    int RetValue;
    pSat  = Pdr_ManSolver(p, k);
    vLits = Pdr_ManCubeToLits( p, k, pCube, 1, 0 );
    RetValue = sat_solver_addclause( pSat, Vec_IntArray(vLits), Vec_IntArray(vLits) + Vec_IntSize(vLits) );
    assert( RetValue == 1 );
    sat_solver_compress( pSat );
}

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

  Synopsis    [Collects values of the RO/RI variables in k-th SAT solver.]

  Description []
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
void Pdr_ManCollectValues( Pdr_Man_t * p, int k, Vec_Int_t * vObjIds, Vec_Int_t * vValues )
{
    sat_solver * pSat;
    Aig_Obj_t * pObj;
    int iVar, i;
    Vec_IntClear( vValues );
    pSat = Pdr_ManSolver(p, k);
    Aig_ManForEachObjVec( vObjIds, p->pAig, pObj, i )
    {
        iVar = Pdr_ObjSatVar( p, k, pObj ); assert( iVar >= 0 );
        Vec_IntPush( vValues, sat_solver_var_value(pSat, iVar) );
    }
}

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

  Synopsis    [Checks if the cube holds (UNSAT) in the given timeframe.]
 
  Description [Return 1/0 if cube or property are proved to hold/fail
  in k-th timeframe.  Returns the predecessor bad state in ppPred.]
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
int Pdr_ManCheckCubeCs( Pdr_Man_t * p, int k, Pdr_Set_t * pCube )
{ 
    sat_solver * pSat;
    Vec_Int_t * vLits;
    int RetValue;
    pSat = Pdr_ManFetchSolver( p, k );
    vLits = Pdr_ManCubeToLits( p, k, pCube, 0, 0 );
    RetValue = sat_solver_solve( pSat, Vec_IntArray(vLits), Vec_IntArray(vLits) + Vec_IntSize(vLits), 0, 0, 0, 0 );
    if ( RetValue == l_Undef )
        return -1;
    return (RetValue == l_False);
}

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

  Synopsis    [Checks if the cube holds (UNSAT) in the given timeframe.]
 
  Description [Return 1/0 if cube or property are proved to hold/fail
  in k-th timeframe.  Returns the predecessor bad state in ppPred.]
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
int Pdr_ManCheckCube( Pdr_Man_t * p, int k, Pdr_Set_t * pCube, Pdr_Set_t ** ppPred, int nConfLimit )
{ 
    int fUseLit = 1;
    int fLitUsed = 0;
    sat_solver * pSat;
    Vec_Int_t * vLits;
    int Lit, RetValue;
    clock_t clk;
    p->nCalls++;
    pSat = Pdr_ManFetchSolver( p, k );
    if ( pCube == NULL ) // solve the property
    {
        clk = clock();
        Lit = toLit( Pdr_ObjSatVar(p, k, Aig_ManCo(p->pAig, p->iOutCur)) ); // pos literal (property fails)
        RetValue = sat_solver_solve( pSat, &Lit, &Lit + 1, nConfLimit, 0, 0, 0 );
        if ( RetValue == l_Undef )
            return -1;
    }
    else // check relative containment in terms of next states
    {
        if ( fUseLit )
        {
            fLitUsed = 1;
            Vec_IntAddToEntry( p->vActVars, k, 1 );
            // add the cube in terms of current state variables
            vLits = Pdr_ManCubeToLits( p, k, pCube, 1, 0 );
            // add activation literal
            Lit = toLit( Pdr_ManFreeVar(p, k) );
            // add activation literal
            Vec_IntPush( vLits, Lit );
            RetValue = sat_solver_addclause( pSat, Vec_IntArray(vLits), Vec_IntArray(vLits) + Vec_IntSize(vLits) );
            assert( RetValue == 1 );
            sat_solver_compress( pSat );
            // create assumptions
            vLits = Pdr_ManCubeToLits( p, k, pCube, 0, 1 );
            // add activation literal
            Vec_IntPush( vLits, lit_neg(Lit) );
        }
        else
            vLits = Pdr_ManCubeToLits( p, k, pCube, 0, 1 );

        // solve 
        clk = clock();
        RetValue = sat_solver_solve( pSat, Vec_IntArray(vLits), Vec_IntArray(vLits) + Vec_IntSize(vLits), nConfLimit, 0, 0, 0 );
        if ( RetValue == l_Undef )
            return -1;
/*
        if ( RetValue == l_True )
        {
            int RetValue2 = Pdr_ManCubeJust( p, k, pCube );
            if ( RetValue2 )
                p->nCasesSS++;
            else
                p->nCasesSU++;
        }
        else
        {
            int RetValue2 = Pdr_ManCubeJust( p, k, pCube );
            if ( RetValue2 )
                p->nCasesUS++;
            else
                p->nCasesUU++;
        }
*/
    }
    clk = clock() - clk;
    p->tSat += clk;
    assert( RetValue != l_Undef );
    if ( RetValue == l_False )
    {
        p->tSatUnsat += clk;
        p->nCallsU++;
        if ( ppPred )
            *ppPred = NULL;
        RetValue = 1;
    }
    else // if ( RetValue == l_True )
    {
        p->tSatSat += clk;
        p->nCallsS++;
        if ( ppPred )
            *ppPred = Pdr_ManTernarySim( p, k, pCube );
        RetValue = 0;
    }

/* // for some reason, it does not work...
    if ( fLitUsed )
    {
        int RetValue;
        Lit = lit_neg(Lit);
        RetValue = sat_solver_addclause( pSat, &Lit, &Lit + 1 );
        assert( RetValue == 1 );
        sat_solver_compress( pSat );
    }
*/
    return RetValue;
}


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ABC_NAMESPACE_IMPL_END