/**CFile**************************************************************** FileName [xsatSolver.c] SystemName [ABC: Logic synthesis and verification system.] PackageName [xSAT - A SAT solver written in C. Read the license file for more info.] Synopsis [Solver internal functions implementation.] Author [Bruno Schmitt ] Affiliation [UC Berkeley / UFRGS] Date [Ver. 1.0. Started - November 10, 2016.] Revision [] ***********************************************************************/ //////////////////////////////////////////////////////////////////////// /// INCLUDES /// //////////////////////////////////////////////////////////////////////// #include #include #include #include #include "xsatHeap.h" #include "xsatSolver.h" #include "xsatUtils.h" ABC_NAMESPACE_IMPL_START //////////////////////////////////////////////////////////////////////// /// FUNCTION DECLARATIONS /// //////////////////////////////////////////////////////////////////////// /**Function************************************************************* Synopsis [] Description [] SideEffects [] SeeAlso [] ***********************************************************************/ static inline int xSAT_SolverDecide( xSAT_Solver_t * s ) { int NextVar = VarUndef; while ( NextVar == VarUndef || Vec_StrEntry( s->vAssigns, NextVar ) != VarX ) { if ( xSAT_HeapSize( s->hOrder ) == 0 ) { NextVar = VarUndef; break; } else NextVar = xSAT_HeapRemoveMin( s->hOrder ); } return NextVar; } /**Function************************************************************* Synopsis [] Description [] SideEffects [] SeeAlso [] ***********************************************************************/ void xSAT_SolverRebuildOrderHeap( xSAT_Solver_t * s ) { Vec_Int_t * vTemp = Vec_IntAlloc( Vec_StrSize( s->vAssigns ) ); int Var; for ( Var = 0; Var < Vec_StrSize( s->vAssigns ); Var++ ) if ( Vec_StrEntry( s->vAssigns, Var ) == VarX ) Vec_IntPush( vTemp, Var ); xSAT_HeapBuild( s->hOrder, vTemp ); Vec_IntFree( vTemp ); } /**Function************************************************************* Synopsis [] Description [] SideEffects [] SeeAlso [] ***********************************************************************/ static inline void xSAT_SolverVarActRescale( xSAT_Solver_t * s ) { int i; unsigned * pActivity = ( unsigned * ) Vec_IntArray( s->vActivity ); for ( i = 0; i < Vec_IntSize( s->vActivity ); i++ ) pActivity[i] >>= 19; s->nVarActInc >>= 19; s->nVarActInc = Abc_MaxInt( s->nVarActInc, ( 1 << 5 ) ); } /**Function************************************************************* Synopsis [] Description [] SideEffects [] SeeAlso [] ***********************************************************************/ static inline void xSAT_SolverVarActBump( xSAT_Solver_t * s, int Var ) { unsigned * pActivity = ( unsigned * ) Vec_IntArray( s->vActivity ); pActivity[Var] += s->nVarActInc; if ( pActivity[Var] & 0x80000000 ) xSAT_SolverVarActRescale( s ); if ( xSAT_HeapInHeap( s->hOrder, Var ) ) xSAT_HeapDecrease( s->hOrder, Var ); } /**Function************************************************************* Synopsis [] Description [] SideEffects [] SeeAlso [] ***********************************************************************/ static inline void xSAT_SolverVarActDecay( xSAT_Solver_t * s ) { s->nVarActInc += ( s->nVarActInc >> 4 ); } /**Function************************************************************* Synopsis [] Description [] SideEffects [] SeeAlso [] ***********************************************************************/ static inline void xSAT_SolverClaActRescale( xSAT_Solver_t * s ) { xSAT_Clause_t * pC; int i, CRef; Vec_IntForEachEntry( s->vLearnts, CRef, i ) { pC = xSAT_SolverReadClause( s, ( unsigned ) CRef ); pC->pData[pC->nSize].Act >>= 14; } s->nClaActInc >>= 14; s->nClaActInc = Abc_MaxInt( s->nClaActInc, ( 1 << 10 ) ); } /**Function************************************************************* Synopsis [] Description [] SideEffects [] SeeAlso [] ***********************************************************************/ static inline void xSAT_SolverClaActBump( xSAT_Solver_t* s, xSAT_Clause_t * pCla ) { pCla->pData[pCla->nSize].Act += s->nClaActInc; if ( pCla->pData[pCla->nSize].Act & 0x80000000 ) xSAT_SolverClaActRescale( s ); } /**Function************************************************************* Synopsis [] Description [] SideEffects [] SeeAlso [] ***********************************************************************/ static inline void xSAT_SolverClaActDecay( xSAT_Solver_t * s ) { s->nClaActInc += ( s->nClaActInc >> 10 ); } /**Function************************************************************* Synopsis [] Description [] SideEffects [] SeeAlso [] ***********************************************************************/ static inline int xSAT_SolverClaCalcLBD( xSAT_Solver_t * s, xSAT_Clause_t * pCla ) { int i; int nLBD = 0; s->nStamp++; for ( i = 0; i < pCla->nSize; i++ ) { int Level = Vec_IntEntry( s->vLevels, xSAT_Lit2Var( pCla->pData[i].Lit ) ); if ( ( unsigned ) Vec_IntEntry( s->vStamp, Level ) != s->nStamp ) { Vec_IntWriteEntry( s->vStamp, Level, ( int ) s->nStamp ); nLBD++; } } return nLBD; } static inline int xSAT_SolverClaCalcLBD2( xSAT_Solver_t * s, Vec_Int_t * vLits ) { int i; int nLBD = 0; s->nStamp++; for ( i = 0; i < Vec_IntSize( vLits ); i++ ) { int Level = Vec_IntEntry( s->vLevels, xSAT_Lit2Var( Vec_IntEntry( vLits, i ) ) ); if ( ( unsigned ) Vec_IntEntry( s->vStamp, Level ) != s->nStamp ) { Vec_IntWriteEntry( s->vStamp, Level, ( int ) s->nStamp ); nLBD++; } } return nLBD; } /**Function************************************************************* Synopsis [] Description [] SideEffects [] SeeAlso [] ***********************************************************************/ unsigned xSAT_SolverClaNew( xSAT_Solver_t * s, Vec_Int_t * vLits , int fLearnt ) { unsigned CRef; xSAT_Clause_t * pCla; xSAT_Watcher_t w1; xSAT_Watcher_t w2; unsigned nWords; assert( Vec_IntSize( vLits ) > 1); assert( fLearnt == 0 || fLearnt == 1 ); nWords = 3 + fLearnt + Vec_IntSize( vLits ); CRef = xSAT_MemAppend( s->pMemory, nWords ); pCla = xSAT_SolverReadClause( s, CRef ); pCla->fLearnt = fLearnt; pCla->fMark = 0; pCla->fReallocd = 0; pCla->fCanBeDel = fLearnt; pCla->nSize = Vec_IntSize( vLits ); memcpy( &( pCla->pData[0].Lit ), Vec_IntArray( vLits ), sizeof( int ) * Vec_IntSize( vLits ) ); if ( fLearnt ) { Vec_IntPush( s->vLearnts, CRef ); pCla->nLBD = xSAT_SolverClaCalcLBD2( s, vLits ); pCla->pData[pCla->nSize].Act = 0; s->Stats.nLearntLits += Vec_IntSize( vLits ); xSAT_SolverClaActBump(s, pCla); } else { Vec_IntPush( s->vClauses, CRef ); s->Stats.nClauseLits += Vec_IntSize( vLits ); } w1.CRef = CRef; w2.CRef = CRef; w1.Blocker = pCla->pData[1].Lit; w2.Blocker = pCla->pData[0].Lit; if ( Vec_IntSize( vLits ) == 2 ) { xSAT_WatchListPush( xSAT_VecWatchListEntry( s->vBinWatches, xSAT_NegLit( pCla->pData[0].Lit ) ), w1 ); xSAT_WatchListPush( xSAT_VecWatchListEntry( s->vBinWatches, xSAT_NegLit( pCla->pData[1].Lit ) ), w2 ); } else { xSAT_WatchListPush( xSAT_VecWatchListEntry( s->vWatches, xSAT_NegLit( pCla->pData[0].Lit ) ), w1 ); xSAT_WatchListPush( xSAT_VecWatchListEntry( s->vWatches, xSAT_NegLit( pCla->pData[1].Lit ) ), w2 ); } return CRef; } /**Function************************************************************* Synopsis [] Description [] SideEffects [] SeeAlso [] ***********************************************************************/ int xSAT_SolverEnqueue( xSAT_Solver_t * s, int Lit, unsigned Reason ) { int Var = xSAT_Lit2Var( Lit ); Vec_StrWriteEntry( s->vAssigns, Var, (char)xSAT_LitSign( Lit ) ); Vec_IntWriteEntry( s->vLevels, Var, xSAT_SolverDecisionLevel( s ) ); Vec_IntWriteEntry( s->vReasons, Var, ( int ) Reason ); Vec_IntPush( s->vTrail, Lit ); return true; } /**Function************************************************************* Synopsis [] Description [] SideEffects [] SeeAlso [] ***********************************************************************/ static inline void xSAT_SolverNewDecision( xSAT_Solver_t * s, int Lit ) { assert( Vec_StrEntry( s->vAssigns, xSAT_Lit2Var( Lit ) ) == VarX ); s->Stats.nDecisions++; Vec_IntPush( s->vTrailLim, Vec_IntSize( s->vTrail ) ); xSAT_SolverEnqueue( s, Lit, CRefUndef ); } /**Function************************************************************* Synopsis [] Description [] SideEffects [] SeeAlso [] ***********************************************************************/ void xSAT_SolverCancelUntil( xSAT_Solver_t * s, int Level ) { int c; if ( xSAT_SolverDecisionLevel( s ) <= Level ) return; for ( c = Vec_IntSize( s->vTrail ) - 1; c >= Vec_IntEntry( s->vTrailLim, Level ); c-- ) { int Var = xSAT_Lit2Var( Vec_IntEntry( s->vTrail, c ) ); Vec_StrWriteEntry( s->vAssigns, Var, VarX ); Vec_IntWriteEntry( s->vReasons, Var, ( int ) CRefUndef ); Vec_StrWriteEntry( s->vPolarity, Var, ( char )xSAT_LitSign( Vec_IntEntry( s->vTrail, c ) ) ); if ( !xSAT_HeapInHeap( s->hOrder, Var ) ) xSAT_HeapInsert( s->hOrder, Var ); } s->iQhead = Vec_IntEntry( s->vTrailLim, Level ); Vec_IntShrink( s->vTrail, Vec_IntEntry( s->vTrailLim, Level ) ); Vec_IntShrink( s->vTrailLim, Level ); } /**Function************************************************************* Synopsis [] Description [] SideEffects [] SeeAlso [] ***********************************************************************/ static int xSAT_SolverIsLitRemovable( xSAT_Solver_t* s, int Lit, int MinLevel ) { int top = Vec_IntSize( s->vTagged ); assert( ( unsigned ) Vec_IntEntry( s->vReasons, xSAT_Lit2Var( Lit ) ) != CRefUndef ); Vec_IntClear( s->vStack ); Vec_IntPush( s->vStack, xSAT_Lit2Var( Lit ) ); while ( Vec_IntSize( s->vStack ) ) { int i; int v = Vec_IntPop( s->vStack ); xSAT_Clause_t* c = xSAT_SolverReadClause(s, ( unsigned ) Vec_IntEntry( s->vReasons, v ) ); int * Lits = &( c->pData[0].Lit ); assert( (unsigned) Vec_IntEntry( s->vReasons, v ) != CRefUndef); if( c->nSize == 2 && Vec_StrEntry( s->vAssigns, xSAT_Lit2Var( Lits[0] ) ) == xSAT_LitSign( xSAT_NegLit( Lits[0] ) ) ) { assert( Vec_StrEntry( s->vAssigns, xSAT_Lit2Var( Lits[1] ) ) == xSAT_LitSign( ( Lits[1] ) ) ); ABC_SWAP( int, Lits[0], Lits[1] ); } for ( i = 1; i < c->nSize; i++ ) { int v = xSAT_Lit2Var( Lits[i] ); if ( !Vec_StrEntry( s->vSeen, v ) && Vec_IntEntry( s->vLevels, v ) ) { if ( ( unsigned ) Vec_IntEntry( s->vReasons, v ) != CRefUndef && ( ( 1 << (Vec_IntEntry( s->vLevels, v ) & 31 ) ) & MinLevel ) ) { Vec_IntPush( s->vStack, v ); Vec_IntPush( s->vTagged, Lits[i] ); Vec_StrWriteEntry( s->vSeen, v, 1 ); } else { int Lit; Vec_IntForEachEntryStart( s->vTagged, Lit, i, top ) Vec_StrWriteEntry( s->vSeen, xSAT_Lit2Var( Lit ), 0 ); Vec_IntShrink( s->vTagged, top ); return 0; } } } } return 1; } /**Function************************************************************* Synopsis [] Description [] SideEffects [] SeeAlso [] ***********************************************************************/ static void xSAT_SolverClaMinimisation( xSAT_Solver_t * s, Vec_Int_t * vLits ) { int * pLits = Vec_IntArray( vLits ); int MinLevel = 0; int i, j; for ( i = 1; i < Vec_IntSize( vLits ); i++ ) { int Level = Vec_IntEntry( s->vLevels, xSAT_Lit2Var( pLits[i] ) ); MinLevel |= 1 << ( Level & 31 ); } /* Remove reduntant literals */ Vec_IntAppend( s->vTagged, vLits ); for ( i = j = 1; i < Vec_IntSize( vLits ); i++ ) if ( ( unsigned ) Vec_IntEntry( s->vReasons, xSAT_Lit2Var( pLits[i] ) ) == CRefUndef || !xSAT_SolverIsLitRemovable( s, pLits[i], MinLevel ) ) pLits[j++] = pLits[i]; Vec_IntShrink( vLits, j ); /* Binary Resolution */ if( Vec_IntSize( vLits ) <= 30 && xSAT_SolverClaCalcLBD2( s, vLits ) <= 6 ) { int nb, l; int Lit; int FlaseLit = xSAT_NegLit( pLits[0] ); xSAT_WatchList_t * ws = xSAT_VecWatchListEntry( s->vBinWatches, FlaseLit ); xSAT_Watcher_t * begin = xSAT_WatchListArray( ws ); xSAT_Watcher_t * end = begin + xSAT_WatchListSize( ws ); xSAT_Watcher_t * pWatcher; s->nStamp++; Vec_IntForEachEntry( vLits, Lit, i ) Vec_IntWriteEntry( s->vStamp, xSAT_Lit2Var( Lit ), ( int ) s->nStamp ); nb = 0; for ( pWatcher = begin; pWatcher < end; pWatcher++ ) { int ImpLit = pWatcher->Blocker; if ( ( unsigned ) Vec_IntEntry( s->vStamp, xSAT_Lit2Var( ImpLit ) ) == s->nStamp && Vec_StrEntry( s->vAssigns, xSAT_Lit2Var( ImpLit ) ) == xSAT_LitSign( ImpLit ) ) { nb++; Vec_IntWriteEntry( s->vStamp, xSAT_Lit2Var( ImpLit ), ( int )( s->nStamp - 1 ) ); } } l = Vec_IntSize( vLits ) - 1; if ( nb > 0 ) { for ( i = 1; i < Vec_IntSize( vLits ) - nb; i++ ) if ( ( unsigned ) Vec_IntEntry( s->vStamp, xSAT_Lit2Var( pLits[i] ) ) != s->nStamp ) { int TempLit = pLits[l]; pLits[l] = pLits[i]; pLits[i] = TempLit; i--; l--; } Vec_IntShrink( vLits, Vec_IntSize( vLits ) - nb ); } } } /**Function************************************************************* Synopsis [] Description [] SideEffects [] SeeAlso [] ***********************************************************************/ static void xSAT_SolverAnalyze( xSAT_Solver_t* s, unsigned ConfCRef, Vec_Int_t * vLearnt, int * OutBtLevel, unsigned * nLBD ) { int * trail = Vec_IntArray( s->vTrail ); int Count = 0; int p = LitUndef; int Idx = Vec_IntSize( s->vTrail ) - 1; int * Lits; int Lit; int i, j; Vec_IntPush( vLearnt, LitUndef ); do { xSAT_Clause_t * pCla; assert( ConfCRef != CRefUndef ); pCla = xSAT_SolverReadClause(s, ConfCRef); Lits = &( pCla->pData[0].Lit ); if( p != LitUndef && pCla->nSize == 2 && Vec_StrEntry( s->vAssigns, xSAT_Lit2Var( Lits[0] ) ) == xSAT_LitSign( xSAT_NegLit( Lits[0] ) ) ) { assert( Vec_StrEntry( s->vAssigns, xSAT_Lit2Var( Lits[1] ) ) == xSAT_LitSign( ( Lits[1] ) ) ); ABC_SWAP( int, Lits[0], Lits[1] ); } if ( pCla->fLearnt ) xSAT_SolverClaActBump( s, pCla ); if ( pCla->fLearnt && pCla->nLBD > 2 ) { unsigned int nLevels = xSAT_SolverClaCalcLBD( s, pCla ); if ( nLevels + 1 < pCla->nLBD ) { if ( pCla->nLBD <= s->Config.nLBDFrozenClause ) pCla->fCanBeDel = 0; pCla->nLBD = nLevels; } } for ( j = ( p == LitUndef ? 0 : 1 ); j < pCla->nSize; j++ ) { int Var = xSAT_Lit2Var( Lits[j] ); if ( Vec_StrEntry( s->vSeen, Var ) == 0 && Vec_IntEntry( s->vLevels, Var ) > 0 ) { Vec_StrWriteEntry( s->vSeen, Var, 1 ); xSAT_SolverVarActBump( s, Var ); if ( Vec_IntEntry( s->vLevels, Var ) >= xSAT_SolverDecisionLevel( s ) ) { Count++; if ( Vec_IntEntry( s->vReasons, Var ) != CRefUndef && xSAT_SolverReadClause( s, Vec_IntEntry( s->vReasons, Var ) )->fLearnt ) Vec_IntPush( s->vLastDLevel, Var ); } else Vec_IntPush( vLearnt, Lits[j] ); } } while ( !Vec_StrEntry( s->vSeen, xSAT_Lit2Var( trail[Idx--] ) ) ); // Next clause to look at p = trail[Idx+1]; ConfCRef = ( unsigned ) Vec_IntEntry( s->vReasons, xSAT_Lit2Var( p ) ); Vec_StrWriteEntry( s->vSeen, xSAT_Lit2Var( p ), 0 ); Count--; } while ( Count > 0 ); Vec_IntArray( vLearnt )[0] = xSAT_NegLit( p ); xSAT_SolverClaMinimisation( s, vLearnt ); // Find the backtrack level Lits = Vec_IntArray( vLearnt ); if ( Vec_IntSize( vLearnt ) == 1 ) *OutBtLevel = 0; else { int iMax = 1; int Max = Vec_IntEntry( s->vLevels, xSAT_Lit2Var( Lits[1] ) ); int Tmp; for (i = 2; i < Vec_IntSize( vLearnt ); i++) if ( Vec_IntEntry( s->vLevels, xSAT_Lit2Var( Lits[i]) ) > Max) { Max = Vec_IntEntry( s->vLevels, xSAT_Lit2Var( Lits[i]) ); iMax = i; } Tmp = Lits[1]; Lits[1] = Lits[iMax]; Lits[iMax] = Tmp; *OutBtLevel = Vec_IntEntry( s->vLevels, xSAT_Lit2Var( Lits[1] ) ); } *nLBD = xSAT_SolverClaCalcLBD2( s, vLearnt ); if ( Vec_IntSize( s->vLastDLevel ) > 0 ) { int Var; Vec_IntForEachEntry( s->vLastDLevel, Var, i ) { if ( xSAT_SolverReadClause( s, Vec_IntEntry( s->vReasons, Var ) )->nLBD < *nLBD ) xSAT_SolverVarActBump( s, Var ); } Vec_IntClear( s->vLastDLevel ); } Vec_IntForEachEntry( s->vTagged, Lit, i ) Vec_StrWriteEntry( s->vSeen, xSAT_Lit2Var( Lit ), 0 ); Vec_IntClear( s->vTagged ); } /**Function************************************************************* Synopsis [] Description [] SideEffects [] SeeAlso [] ***********************************************************************/ unsigned xSAT_SolverPropagate( xSAT_Solver_t* s ) { unsigned hConfl = CRefUndef; int * Lits; int NegLit; int nProp = 0; while ( s->iQhead < Vec_IntSize( s->vTrail ) ) { int p = Vec_IntEntry( s->vTrail, s->iQhead++ ); xSAT_WatchList_t* ws = xSAT_VecWatchListEntry( s->vBinWatches, p ); xSAT_Watcher_t* begin = xSAT_WatchListArray( ws ); xSAT_Watcher_t* end = begin + xSAT_WatchListSize( ws ); xSAT_Watcher_t *i, *j; nProp++; for ( i = begin; i < end; i++ ) { if ( Vec_StrEntry( s->vAssigns, xSAT_Lit2Var( i->Blocker ) ) == VarX ) xSAT_SolverEnqueue( s, i->Blocker, i->CRef ); else if ( Vec_StrEntry( s->vAssigns, xSAT_Lit2Var( i->Blocker ) ) == xSAT_LitSign( xSAT_NegLit( i->Blocker ) ) ) return i->CRef; } ws = xSAT_VecWatchListEntry( s->vWatches, p ); begin = xSAT_WatchListArray( ws ); end = begin + xSAT_WatchListSize( ws ); for ( i = j = begin; i < end; ) { xSAT_Clause_t * pCla; xSAT_Watcher_t w; if ( Vec_StrEntry( s->vAssigns, xSAT_Lit2Var( i->Blocker ) ) == xSAT_LitSign( i->Blocker ) ) { *j++ = *i++; continue; } pCla = xSAT_SolverReadClause( s, i->CRef ); Lits = &( pCla->pData[0].Lit ); // Make sure the false literal is data[1]: NegLit = xSAT_NegLit( p ); if ( Lits[0] == NegLit ) { Lits[0] = Lits[1]; Lits[1] = NegLit; } assert( Lits[1] == NegLit ); w.CRef = i->CRef; w.Blocker = Lits[0]; // If 0th watch is true, then clause is already satisfied. if ( Lits[0] != i->Blocker && Vec_StrEntry( s->vAssigns, xSAT_Lit2Var( Lits[0] ) ) == xSAT_LitSign( Lits[0] ) ) *j++ = w; else { // Look for new watch: int * stop = Lits + pCla->nSize; int * k; for ( k = Lits + 2; k < stop; k++ ) { if (Vec_StrEntry( s->vAssigns, xSAT_Lit2Var( *k ) ) != !xSAT_LitSign( *k ) ) { Lits[1] = *k; *k = NegLit; xSAT_WatchListPush( xSAT_VecWatchListEntry( s->vWatches, xSAT_NegLit( Lits[1] ) ), w ); goto next; } } *j++ = w; // Clause is unit under assignment: if (Vec_StrEntry( s->vAssigns, xSAT_Lit2Var( Lits[0] ) ) == xSAT_LitSign( xSAT_NegLit( Lits[0] ) ) ) { hConfl = i->CRef; i++; s->iQhead = Vec_IntSize( s->vTrail ); // Copy the remaining watches: while (i < end) *j++ = *i++; } else xSAT_SolverEnqueue( s, Lits[0], i->CRef ); } next: i++; } s->Stats.nInspects += j - xSAT_WatchListArray( ws ); xSAT_WatchListShrink( ws, j - xSAT_WatchListArray( ws ) ); } s->Stats.nPropagations += nProp; s->nPropSimplify -= nProp; return hConfl; } /**Function************************************************************* Synopsis [] Description [] SideEffects [] SeeAlso [] ***********************************************************************/ void xSAT_SolverReduceDB( xSAT_Solver_t * s ) { static abctime TimeTotal = 0; abctime clk = Abc_Clock(); int nLearnedOld = Vec_IntSize( s->vLearnts ); int i, limit; unsigned CRef; xSAT_Clause_t * pCla; xSAT_Clause_t ** learnts_cls; learnts_cls = ABC_ALLOC( xSAT_Clause_t *, nLearnedOld ); Vec_IntForEachEntry( s->vLearnts, CRef, i ) learnts_cls[i] = xSAT_SolverReadClause(s, CRef); limit = nLearnedOld / 2; xSAT_UtilSort((void **) learnts_cls, nLearnedOld, (int (*)( const void *, const void * )) xSAT_ClauseCompare); if ( learnts_cls[nLearnedOld / 2]->nLBD <= 3 ) s->nRC2 += s->Config.nSpecialIncReduce; if ( learnts_cls[nLearnedOld - 1]->nLBD <= 5 ) s->nRC2 += s->Config.nSpecialIncReduce; Vec_IntClear( s->vLearnts ); for ( i = 0; i < nLearnedOld; i++ ) { unsigned CRef; pCla = learnts_cls[i]; CRef = xSAT_MemCRef( s->pMemory, ( unsigned * ) pCla ); assert( pCla->fMark == 0 ); if ( pCla->fCanBeDel && pCla->nLBD > 2 && pCla->nSize > 2 && (unsigned) Vec_IntEntry( s->vReasons, xSAT_Lit2Var( pCla->pData[0].Lit ) ) != CRef && ( i < limit ) ) { pCla->fMark = 1; s->Stats.nLearntLits -= pCla->nSize; xSAT_WatchListRemove( xSAT_VecWatchListEntry( s->vWatches, xSAT_NegLit( pCla->pData[0].Lit ) ), CRef ); xSAT_WatchListRemove( xSAT_VecWatchListEntry( s->vWatches, xSAT_NegLit( pCla->pData[1].Lit ) ), CRef ); } else { if ( !pCla->fCanBeDel ) limit++; pCla->fCanBeDel = 1; Vec_IntPush( s->vLearnts, CRef ); } } ABC_FREE( learnts_cls ); TimeTotal += Abc_Clock() - clk; if ( s->Config.fVerbose ) { Abc_Print(1, "reduceDB: Keeping %7d out of %7d clauses (%5.2f %%) ", Vec_IntSize( s->vLearnts ), nLearnedOld, 100.0 * Vec_IntSize( s->vLearnts ) / nLearnedOld ); Abc_PrintTime( 1, "Time", TimeTotal ); } xSAT_SolverGarbageCollect(s); } /**Function************************************************************* Synopsis [] Description [] SideEffects [] SeeAlso [] ***********************************************************************/ char xSAT_SolverSearch( xSAT_Solver_t * s ) { iword conflictC = 0; s->Stats.nStarts++; for (;;) { unsigned hConfl = xSAT_SolverPropagate( s ); if ( hConfl != CRefUndef ) { /* Conflict */ int BacktrackLevel; unsigned nLBD; unsigned CRef; s->Stats.nConflicts++; conflictC++; if ( xSAT_SolverDecisionLevel( s ) == 0 ) return LBoolFalse; xSAT_BQueuePush( s->bqTrail, Vec_IntSize( s->vTrail ) ); if ( s->Stats.nConflicts > s->Config.nFirstBlockRestart && xSAT_BQueueIsValid( s->bqLBD ) && ( Vec_IntSize( s->vTrail ) > ( s->Config.R * ( iword ) xSAT_BQueueAvg( s->bqTrail ) ) ) ) xSAT_BQueueClean(s->bqLBD); Vec_IntClear( s->vLearntClause ); xSAT_SolverAnalyze( s, hConfl, s->vLearntClause, &BacktrackLevel, &nLBD ); s->nSumLBD += nLBD; xSAT_BQueuePush( s->bqLBD, nLBD ); xSAT_SolverCancelUntil( s, BacktrackLevel ); CRef = Vec_IntSize( s->vLearntClause ) == 1 ? CRefUndef : xSAT_SolverClaNew( s, s->vLearntClause , 1 ); xSAT_SolverEnqueue( s, Vec_IntEntry( s->vLearntClause , 0 ), CRef ); xSAT_SolverVarActDecay( s ); xSAT_SolverClaActDecay( s ); } else { /* No conflict */ int NextVar; if ( xSAT_BQueueIsValid( s->bqLBD ) && ( ( ( iword )xSAT_BQueueAvg( s->bqLBD ) * s->Config.K ) > ( s->nSumLBD / s->Stats.nConflicts ) ) ) { xSAT_BQueueClean( s->bqLBD ); xSAT_SolverCancelUntil( s, 0 ); return LBoolUndef; } // Simplify the set of problem clauses: if ( xSAT_SolverDecisionLevel( s ) == 0 ) xSAT_SolverSimplify( s ); // Reduce the set of learnt clauses: if ( s->Stats.nConflicts >= s->nConfBeforeReduce ) { s->nRC1 = ( s->Stats.nConflicts / s->nRC2 ) + 1; xSAT_SolverReduceDB(s); s->nRC2 += s->Config.nIncReduce; s->nConfBeforeReduce = s->nRC1 * s->nRC2; } // New variable decision: NextVar = xSAT_SolverDecide( s ); if ( NextVar == VarUndef ) return LBoolTrue; xSAT_SolverNewDecision( s, xSAT_Var2Lit( NextVar, ( int ) Vec_StrEntry( s->vPolarity, NextVar ) ) ); } } return LBoolUndef; // cannot happen } /**Function************************************************************* Synopsis [] Description [] SideEffects [] SeeAlso [] ***********************************************************************/ void xSAT_SolverClaRealloc( xSAT_Mem_t * pDest, xSAT_Mem_t * pSrc, unsigned * pCRef ) { unsigned nNewCRef; xSAT_Clause_t * pNewCla; xSAT_Clause_t * pOldCla = xSAT_MemClauseHand( pSrc, *pCRef ); if ( pOldCla->fReallocd ) { *pCRef = ( unsigned ) pOldCla->nSize; return; } nNewCRef = xSAT_MemAppend( pDest, 3 + pOldCla->fLearnt + pOldCla->nSize ); pNewCla = xSAT_MemClauseHand( pDest, nNewCRef ); memcpy( pNewCla, pOldCla, (size_t)(( 3 + pOldCla->fLearnt + pOldCla->nSize ) * 4) ); pOldCla->fReallocd = 1; pOldCla->nSize = ( unsigned ) nNewCRef; *pCRef = nNewCRef; } /**Function************************************************************* Synopsis [] Description [] SideEffects [] SeeAlso [] ***********************************************************************/ void xSAT_SolverGarbageCollect( xSAT_Solver_t * s ) { int i; unsigned * pArray; xSAT_Mem_t * pNewMemMngr = xSAT_MemAlloc( xSAT_MemCap( s->pMemory ) - xSAT_MemWastedCap( s->pMemory ) ); for ( i = 0; i < 2 * Vec_StrSize( s->vAssigns ); i++ ) { xSAT_WatchList_t* ws = xSAT_VecWatchListEntry( s->vWatches, i); xSAT_Watcher_t* begin = xSAT_WatchListArray(ws); xSAT_Watcher_t* end = begin + xSAT_WatchListSize(ws); xSAT_Watcher_t *w; for ( w = begin; w != end; w++ ) xSAT_SolverClaRealloc( pNewMemMngr, s->pMemory, &(w->CRef) ); ws = xSAT_VecWatchListEntry( s->vBinWatches, i); begin = xSAT_WatchListArray(ws); end = begin + xSAT_WatchListSize(ws); for ( w = begin; w != end; w++ ) xSAT_SolverClaRealloc( pNewMemMngr, s->pMemory, &(w->CRef) ); } for ( i = 0; i < Vec_IntSize( s->vTrail ); i++ ) if ( ( unsigned ) Vec_IntEntry( s->vReasons, xSAT_Lit2Var( Vec_IntEntry( s->vTrail, i ) ) ) != CRefUndef ) xSAT_SolverClaRealloc( pNewMemMngr, s->pMemory, ( unsigned * ) &( Vec_IntArray( s->vReasons )[xSAT_Lit2Var( Vec_IntEntry( s->vTrail, i ) )] ) ); pArray = ( unsigned * ) Vec_IntArray( s->vLearnts ); for ( i = 0; i < Vec_IntSize( s->vLearnts ); i++ ) xSAT_SolverClaRealloc( pNewMemMngr, s->pMemory, &(pArray[i]) ); pArray = ( unsigned * ) Vec_IntArray( s->vClauses ); for ( i = 0; i < Vec_IntSize( s->vClauses ); i++ ) xSAT_SolverClaRealloc( pNewMemMngr, s->pMemory, &(pArray[i]) ); xSAT_MemFree( s->pMemory ); s->pMemory = pNewMemMngr; } ABC_NAMESPACE_IMPL_END