void solver_reducedb(solver* s)
{
int i, j;
double extra_lim = s->cla_inc / vecp_size(&s->learnts);
/* Remove any clause below this activity */
clause** learnts = (clause**)vecp_begin(&s->learnts);
clause** reasons = s->reasons;
sort(vecp_begin(&s->learnts), vecp_size(&s->learnts), clause_cmp);
for (i = j = 0; i < vecp_size(&s->learnts) / 2; i++){
if (clause_size(learnts[i]) > 2
&& reasons[lit_var(*clause_begin(learnts[i]))]
!= learnts[i])
clause_remove(s,learnts[i]);
else
learnts[j++] = learnts[i];
}
for (; i < vecp_size(&s->learnts); i++){
if (clause_size(learnts[i]) > 2
&& reasons[lit_var(*clause_begin(learnts[i]))]
!= learnts[i]
&& clause_activity(learnts[i]) < extra_lim)
clause_remove(s,learnts[i]);
else
learnts[j++] = learnts[i];
}
/* printf("reducedb deleted %d\n", vecp_size(&s->learnts) - j); */
vecp_resize(&s->learnts,j);
}
static inline void solver_canceluntil(solver* s, int level) {
lit* trail;
lbool* values;
clause** reasons;
int bound;
int c;
if (solver_dlevel(s) <= level)
return;
trail = s->trail;
values = s->assigns;
reasons = s->reasons;
bound = (veci_begin(&s->trail_lim))[level];
for (c = s->qtail-1; c >= bound; c--) {
int x = lit_var(trail[c]);
values [x] = l_Undef;
reasons[x] = (clause*)0;
}
for (c = s->qhead-1; c >= bound; c--)
order_unassigned(s,lit_var(trail[c]));
s->qhead = s->qtail = bound;
veci_resize(&s->trail_lim,level);
}
/**Function*************************************************************
Synopsis [Propagate one assignment.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
static inline Pr_Cls_t * Pr_ManPropagateOne( Pr_Man_t * p, lit Lit )
{
Pr_Cls_t ** ppPrev, * pCur, * pTemp;
lit LitF = lit_neg(Lit);
int i;
// iterate through the literals
ppPrev = p->pWatches + Lit;
for ( pCur = p->pWatches[Lit]; pCur; pCur = *ppPrev )
{
// make sure the false literal is in the second literal of the clause
if ( pCur->pLits[0] == LitF )
{
pCur->pLits[0] = pCur->pLits[1];
pCur->pLits[1] = LitF;
pTemp = pCur->pNext0;
pCur->pNext0 = pCur->pNext1;
pCur->pNext1 = pTemp;
}
assert( pCur->pLits[1] == LitF );
// if the first literal is true, the clause is satisfied
if ( pCur->pLits[0] == p->pAssigns[lit_var(pCur->pLits[0])] )
{
ppPrev = &pCur->pNext1;
continue;
}
// look for a new literal to watch
for ( i = 2; i < (int)pCur->nLits; i++ )
{
// skip the case when the literal is false
if ( lit_neg(pCur->pLits[i]) == p->pAssigns[lit_var(pCur->pLits[i])] )
continue;
// the literal is either true or unassigned - watch it
pCur->pLits[1] = pCur->pLits[i];
pCur->pLits[i] = LitF;
// remove this clause from the watch list of Lit
*ppPrev = pCur->pNext1;
// add this clause to the watch list of pCur->pLits[i] (now it is pCur->pLits[1])
Pr_ManWatchClause( p, pCur, pCur->pLits[1] );
break;
}
if ( i < (int)pCur->nLits ) // found new watch
continue;
// clause is unit - enqueue new implication
if ( Pr_ManEnqueue(p, pCur->pLits[0], pCur) )
{
ppPrev = &pCur->pNext1;
continue;
}
// conflict detected - return the conflict clause
return pCur;
}
return NULL;
}
/**Function*************************************************************
Synopsis [Lifts the clause to depend on NS variables.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
void Fra_ClauRemapClause( int * pMap, Vec_Int_t * vClause, Vec_Int_t * vRemapped, int fInv )
{
int iLit, i;
Vec_IntClear( vRemapped );
Vec_IntForEachEntry( vClause, iLit, i )
{
assert( pMap[lit_var(iLit)] >= 0 );
iLit = toLitCond( pMap[lit_var(iLit)], lit_sign(iLit) ^ fInv );
Vec_IntPush( vRemapped, iLit );
}
bool solver_addclause(solver* s, lit* begin, lit* end)
{
lit *i,*j;
int maxvar;
lbool* values;
lit last;
if (begin == end) return false;
/* printlits(begin,end); printf("\n"); */
/* insertion sort */
maxvar = lit_var(*begin);
for (i = begin + 1; i < end; i++){
lit l = *i;
maxvar = lit_var(l) > maxvar ? lit_var(l) : maxvar;
for (j = i; j > begin && *(j-1) > l; j--)
*j = *(j-1);
*j = l;
}
solver_setnvars(s,maxvar+1);
/* printlits(begin,end); printf("\n"); */
values = s->assigns;
/* delete duplicates */
last = lit_Undef;
for (i = j = begin; i < end; i++){
/* printf("lit: "L_LIT", value = %d\n", L_lit(*i),
(lit_sign(*i) ? -values[lit_var(*i)] : values[lit_var(*i)])); */
lbool sig = !lit_sign(*i); sig += sig - 1;
if (*i == lit_neg(last) || sig == values[lit_var(*i)])
return true; /* tautology */
else if (*i != last && values[lit_var(*i)] == l_Undef)
last = *j++ = *i;
}
/* printf("final: "); printlits(begin,j); printf("\n"); */
if (j == begin) /* empty clause */
return false;
else if (j - begin == 1) /* unit clause */
return enqueue(s,*begin,(clause*)0);
/* create new clause */
vecp_push(&s->clauses,clause_new(s,begin,j,0));
s->stats.clauses++;
s->stats.clauses_literals += j - begin;
return true;
}
static inline bool enqueue(solver* s, lit l, clause* from)
{
lbool* values = s->assigns;
int v = lit_var(l);
lbool val = values[v];
lbool sig;
#ifdef VERBOSEDEBUG
printf(L_IND"enqueue("L_LIT")\n", L_ind, L_lit(l));
#endif
/* lbool */ sig = !lit_sign(l); sig += sig - 1;
if (val != l_Undef){
return val == sig;
}else{
/* New fact -- store it. */
int* levels;
clause** reasons;
#ifdef VERBOSEDEBUG
printf(L_IND"bind("L_LIT")\n", L_ind, L_lit(l));
#endif
/* int* */ levels = s->levels;
/* clause** */ reasons = s->reasons;
values [v] = sig;
levels [v] = solver_dlevel(s);
reasons[v] = from;
s->trail[s->qtail++] = l;
order_assigned(s, v);
return true;
}
}
static inline void assume(solver* s, lit l){
assert(s->qtail == s->qhead);
assert(s->assigns[lit_var(l)] == l_Undef);
#ifdef VERBOSEDEBUG
printf(L_IND"assume("L_LIT")\n", L_ind, L_lit(l));
#endif
veci_push(&s->trail_lim,s->qtail);
enqueue(s,l,(clause*)0);
}
/**Function*************************************************************
Synopsis [Records implication.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
static inline int Pr_ManEnqueue( Pr_Man_t * p, lit Lit, Pr_Cls_t * pReason )
{
int Var = lit_var(Lit);
if ( p->pAssigns[Var] != LIT_UNDEF )
return p->pAssigns[Var] == Lit;
p->pAssigns[Var] = Lit;
p->pReasons[Var] = pReason;
p->pTrail[p->nTrailSize++] = Lit;
//printf( "assigning var %d value %d\n", Var, !lit_sign(Lit) );
return 1;
}
/**Function*************************************************************
Synopsis [Records implication.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
static inline void Pr_ManCancelUntil( Pr_Man_t * p, int Level )
{
lit Lit;
int i, Var;
for ( i = p->nTrailSize - 1; i >= Level; i-- )
{
Lit = p->pTrail[i];
Var = lit_var( Lit );
p->pReasons[Var] = NULL;
p->pAssigns[Var] = LIT_UNDEF;
//printf( "cancelling var %d\n", Var );
}
p->nTrailSize = Level;
}
extern "C" value C_create_lit(value v, value solver_In,value sign_In)
{
CAMLparam3(v, solver_In,sign_In);
solver_c s = (solver_c) Field(solver_In, 0);
int var_id = Int_val(v);
// printf("minisat_ocaml_wrapper: new lit var id: %i\n",var_id);
//assume true == True, false == False
int sign = Bool_val(sign_In);
addVar (s,var_id);
lit_c lit = lit_var (var_id, sign);
value val = alloc(1, Abstract_tag);
Field(val,0) = (value) lit;
CAMLreturn(val);
}
bool solver_addclause(solver* s, lit* begin, lit* end)
{
lit *i,*j;
int maxvar;
if (begin == end) return false; // Empty clause
// insertion sort
maxvar = lit_var(*begin);
for (i = begin + 1; i < end; i++){
lit l = *i;
maxvar = lit_var(l) > maxvar ? lit_var(l) : maxvar;
for (j = i; j > begin && *(j-1) > l; j--)
*j = *(j-1);
*j = l;
}
solver_setnvars(s,maxvar+1);
// create new clause
vecp_push(&s->clauses,clause_new(s,begin,end));
s->tail++; // tail == # of clauses at first.
return true;
}
static lbool clause_simplify(solver* s, clause* c)
{
lit* lits = clause_begin(c);
lbool* values = s->assigns;
int i;
assert(solver_dlevel(s) == 0);
for (i = 0; i < clause_size(c); i++){
lbool sig = !lit_sign(lits[i]); sig += sig - 1;
if (values[lit_var(lits[i])] == sig)
return l_True;
}
return l_False;
}
bool solver_simplify(solver* s)
{
clause** reasons;
int type;
assert(solver_dlevel(s) == 0);
if (solver_propagate(s) != 0)
return false;
if (s->qhead == s->simpdb_assigns || s->simpdb_props > 0)
return true;
reasons = s->reasons;
for (type = 0; type < 2; type++){
vecp* cs = type ? &s->learnts : &s->clauses;
clause** cls = (clause**)vecp_begin(cs);
int i, j;
for (j = i = 0; i < vecp_size(cs); i++){
if (reasons[lit_var(*clause_begin(cls[i]))] != cls[i] &&
clause_simplify(s,cls[i]) == l_True)
clause_remove(s,cls[i]);
else
cls[j++] = cls[i];
}
vecp_resize(cs,j);
}
s->simpdb_assigns = s->qhead;
/* (shouldn't depend on 'stats' really, but it will do for now) */
s->simpdb_props = (int)(s->stats.clauses_literals
+ s->stats.learnts_literals);
return true;
}
/**Function*************************************************************
Synopsis [Traces the proof for one clause.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
int Pr_ManProofTraceOne( Pr_Man_t * p, Pr_Cls_t * pConflict, Pr_Cls_t * pFinal )
{
Pr_Cls_t * pReason;
int i, v, Var, PrevId;
int fPrint = 0;
int clk = clock();
// collect resolvent literals
if ( p->fProofVerif )
{
assert( (int)pConflict->nLits <= p->nResLitsAlloc );
memcpy( p->pResLits, pConflict->pLits, sizeof(lit) * pConflict->nLits );
p->nResLits = pConflict->nLits;
}
// mark all the variables in the conflict as seen
for ( v = 0; v < (int)pConflict->nLits; v++ )
p->pSeens[lit_var(pConflict->pLits[v])] = 1;
// start the anticedents
// pFinal->pAntis = Vec_PtrAlloc( 32 );
// Vec_PtrPush( pFinal->pAntis, pConflict );
if ( p->nClausesA )
pFinal->uTruth = pConflict->uTruth;
// follow the trail backwards
PrevId = (int)pConflict->pProof;
for ( i = p->nTrailSize - 1; i >= 0; i-- )
{
// skip literals that are not involved
Var = lit_var(p->pTrail[i]);
if ( !p->pSeens[Var] )
continue;
p->pSeens[Var] = 0;
// skip literals of the resulting clause
pReason = p->pReasons[Var];
if ( pReason == NULL )
continue;
assert( p->pTrail[i] == pReason->pLits[0] );
// add the variables to seen
for ( v = 1; v < (int)pReason->nLits; v++ )
p->pSeens[lit_var(pReason->pLits[v])] = 1;
// record the reason clause
assert( pReason->pProof > 0 );
p->Counter++;
if ( p->fProofWrite )
fprintf( p->pManProof, "%d * %d %d 0\n", p->Counter, PrevId, (int)pReason->pProof );
PrevId = p->Counter;
if ( p->nClausesA )
{
if ( p->pVarTypes[Var] == 1 ) // var of A
pFinal->uTruth |= pReason->uTruth;
else
pFinal->uTruth &= pReason->uTruth;
}
// resolve the temporary resolvent with the reason clause
if ( p->fProofVerif )
{
int v1, v2;
if ( fPrint )
Pr_ManPrintResolvent( p->pResLits, p->nResLits );
// check that the var is present in the resolvent
for ( v1 = 0; v1 < p->nResLits; v1++ )
if ( lit_var(p->pResLits[v1]) == Var )
break;
if ( v1 == p->nResLits )
printf( "Recording clause %d: Cannot find variable %d in the temporary resolvent.\n", pFinal->Id, Var );
if ( p->pResLits[v1] != lit_neg(pReason->pLits[0]) )
printf( "Recording clause %d: The resolved variable %d is in the wrong polarity.\n", pFinal->Id, Var );
// remove this variable from the resolvent
assert( lit_var(p->pResLits[v1]) == Var );
p->nResLits--;
for ( ; v1 < p->nResLits; v1++ )
p->pResLits[v1] = p->pResLits[v1+1];
// add variables of the reason clause
for ( v2 = 1; v2 < (int)pReason->nLits; v2++ )
{
for ( v1 = 0; v1 < p->nResLits; v1++ )
if ( lit_var(p->pResLits[v1]) == lit_var(pReason->pLits[v2]) )
break;
// if it is a new variable, add it to the resolvent
if ( v1 == p->nResLits )
{
if ( p->nResLits == p->nResLitsAlloc )
printf( "Recording clause %d: Ran out of space for intermediate resolvent.\n, pFinal->Id" );
p->pResLits[ p->nResLits++ ] = pReason->pLits[v2];
continue;
}
// if the variable is the same, the literal should be the same too
if ( p->pResLits[v1] == pReason->pLits[v2] )
continue;
// the literal is different
printf( "Recording clause %d: Trying to resolve the clause with more than one opposite literal.\n", pFinal->Id );
}
}
// Vec_PtrPush( pFinal->pAntis, pReason );
}
// unmark all seen variables
// for ( i = p->nTrailSize - 1; i >= 0; i-- )
// p->pSeens[lit_var(p->pTrail[i])] = 0;
// check that the literals are unmarked
// for ( i = p->nTrailSize - 1; i >= 0; i-- )
// assert( p->pSeens[lit_var(p->pTrail[i])] == 0 );
// use the resulting clause to check the correctness of resolution
if ( p->fProofVerif )
{
int v1, v2;
if ( fPrint )
Pr_ManPrintResolvent( p->pResLits, p->nResLits );
for ( v1 = 0; v1 < p->nResLits; v1++ )
{
for ( v2 = 0; v2 < (int)pFinal->nLits; v2++ )
if ( pFinal->pLits[v2] == p->pResLits[v1] )
break;
if ( v2 < (int)pFinal->nLits )
continue;
break;
}
if ( v1 < p->nResLits )
{
printf( "Recording clause %d: The final resolvent is wrong.\n", pFinal->Id );
Pr_ManPrintClause( pConflict );
Pr_ManPrintResolvent( p->pResLits, p->nResLits );
Pr_ManPrintClause( pFinal );
}
}
p->timeTrace += clock() - clk;
// return the proof pointer
if ( p->nClausesA )
{
Pr_ManPrintInterOne( p, pFinal );
}
return p->Counter;
}
bool solver_solve(solver* s, lit* begin, lit* end)
{
double nof_conflicts = 100;
double nof_learnts = solver_nclauses(s) / 3;
lbool status = l_Undef;
lbool* values = s->assigns;
lit* i;
/* printf("solve: "); printlits(begin, end); printf("\n"); */
for (i = begin; i < end; i++){
switch (lit_sign(*i) ? -values[lit_var(*i)]
: values[lit_var(*i)]){
case 1: /* l_True: */
break;
case 0: /* l_Undef */
assume(s, *i);
if (solver_propagate(s) == NULL)
break;
/* falltrough */
case -1: /* l_False */
solver_canceluntil(s, 0);
return false;
}
}
s->root_level = solver_dlevel(s);
if (s->verbosity >= 1){
printf("==================================[MINISAT]============"
"=======================\n");
printf("| Conflicts | ORIGINAL | LEARNT "
" | Progress |\n");
printf("| | Clauses Literals | Limit Clauses Litera"
"ls Lit/Cl | |\n");
printf("======================================================="
"=======================\n");
}
while (status == l_Undef){
double Ratio = (s->stats.learnts == 0)? 0.0 :
s->stats.learnts_literals / (double)s->stats.learnts;
if (s->verbosity >= 1){
printf("| %9.0f | %7.0f %8.0f | %7.0f %7.0f %8.0f %7.1f | %"
"6.3f %% |\n",
(double)s->stats.conflicts,
(double)s->stats.clauses,
(double)s->stats.clauses_literals,
(double)nof_learnts,
(double)s->stats.learnts,
(double)s->stats.learnts_literals,
Ratio,
s->progress_estimate*100);
fflush(stdout);
}
status = solver_search(s,(int)nof_conflicts, (int)nof_learnts);
nof_conflicts *= 1.5;
nof_learnts *= 1.1;
}
if (s->verbosity >= 1)
printf("======================================================="
"=======================\n");
solver_canceluntil(s,0);
return status != l_False;
}
/**Function*************************************************************
Synopsis [Adds one clause to the manager.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
int Pr_ManAddClause( Pr_Man_t * p, lit * pBeg, lit * pEnd, int fRoot, int fClauseA )
{
Pr_Cls_t * pClause;
lit Lit, * i, * j;
int nSize, VarMax;
// process the literals
if ( pBeg < pEnd )
{
// insertion sort
VarMax = lit_var( *pBeg );
for ( i = pBeg + 1; i < pEnd; i++ )
{
Lit = *i;
VarMax = lit_var(Lit) > VarMax ? lit_var(Lit) : VarMax;
for ( j = i; j > pBeg && *(j-1) > Lit; j-- )
*j = *(j-1);
*j = Lit;
}
// make sure there is no duplicated variables
for ( i = pBeg + 1; i < pEnd; i++ )
assert( lit_var(*(i-1)) != lit_var(*i) );
// resize the manager
Pr_ManResize( p, VarMax+1 );
}
// get memory for the clause
nSize = sizeof(Pr_Cls_t) + sizeof(lit) * (pEnd - pBeg);
pClause = (Pr_Cls_t *)Pr_ManMemoryFetch( p, nSize );
memset( pClause, 0, sizeof(Pr_Cls_t) );
// assign the clause
assert( !fClauseA || fRoot ); // clause of A is always a root clause
p->nRoots += fRoot;
p->nClausesA += fClauseA;
pClause->Id = p->nClauses++;
pClause->fA = fClauseA;
pClause->fRoot = fRoot;
pClause->nLits = pEnd - pBeg;
memcpy( pClause->pLits, pBeg, sizeof(lit) * (pEnd - pBeg) );
// add the clause to the list
if ( p->pHead == NULL )
p->pHead = pClause;
if ( p->pTail == NULL )
p->pTail = pClause;
else
{
p->pTail->pNext = pClause;
p->pTail = pClause;
}
// mark the first learnt clause
if ( p->pLearnt == NULL && !pClause->fRoot )
p->pLearnt = pClause;
// add the empty clause
if ( pClause->nLits == 0 )
{
if ( p->pEmpty )
printf( "More than one empty clause!\n" );
p->pEmpty = pClause;
}
return 1;
}
static inline int lit_check(lit l, int n) { return l >= 0 && lit_var(l) < n; }
int Pdr_ObjSatVar2( Pdr_Man_t * p, int k, Aig_Obj_t * pObj, int Level, int Pol )
{
Vec_Int_t * vLits;
sat_solver * pSat;
Vec_Int_t * vVar2Ids = (Vec_Int_t *)Vec_PtrEntry(&p->vVar2Ids, k);
int nVarCount = Vec_IntSize(vVar2Ids);
int iVarThis = Pdr_ObjSatVar2FindOrAdd( p, k, pObj );
int * pLit, i, iVar, iClaBeg, iClaEnd, RetValue;
int PolPres = (iVarThis & 3);
iVarThis >>= 2;
if ( Aig_ObjIsCi(pObj) )
return iVarThis;
// Pol = 3;
// if ( nVarCount != Vec_IntSize(vVar2Ids) || (Pol & ~PolPres) )
if ( (Pol & ~PolPres) )
{
*Vec_IntEntryP( p->pvId2Vars + Aig_ObjId(pObj), k ) |= Pol;
iClaBeg = p->pCnf2->pObj2Clause[Aig_ObjId(pObj)];
iClaEnd = iClaBeg + p->pCnf2->pObj2Count[Aig_ObjId(pObj)];
assert( iClaBeg < iClaEnd );
/*
if ( (Pol & ~PolPres) != 3 )
for ( i = iFirstClause; i < iFirstClause + nClauses; i++ )
{
printf( "Clause %5d : ", i );
for ( iVar = 0; iVar < 4; iVar++ )
printf( "%d ", ((unsigned)p->pCnf2->pClaPols[i] >> (2*iVar)) & 3 );
printf( " " );
for ( pLit = p->pCnf2->pClauses[i]; pLit < p->pCnf2->pClauses[i+1]; pLit++ )
printf( "%6d ", *pLit );
printf( "\n" );
}
*/
pSat = Pdr_ManSolver(p, k);
vLits = Vec_WecEntry( p->vVLits, Level );
if ( (Pol & ~PolPres) == 3 )
{
assert( nVarCount + 1 == Vec_IntSize(vVar2Ids) );
for ( i = iClaBeg; i < iClaEnd; i++ )
{
Vec_IntClear( vLits );
Vec_IntPush( vLits, toLitCond( iVarThis, lit_sign(p->pCnf2->pClauses[i][0]) ) );
for ( pLit = p->pCnf2->pClauses[i]+1; pLit < p->pCnf2->pClauses[i+1]; pLit++ )
{
iVar = Pdr_ObjSatVar2( p, k, Aig_ManObj(p->pAig, lit_var(*pLit)), Level+1, 3 );
Vec_IntPush( vLits, toLitCond( iVar, lit_sign(*pLit) ) );
}
RetValue = sat_solver_addclause( pSat, Vec_IntArray(vLits), Vec_IntArray(vLits)+Vec_IntSize(vLits) );
assert( RetValue );
(void) RetValue;
}
}
else // if ( (Pol & ~PolPres) == 2 || (Pol & ~PolPres) == 1 ) // write pos/neg polarity
{
assert( (Pol & ~PolPres) );
for ( i = iClaBeg; i < iClaEnd; i++ )
if ( 2 - !Abc_LitIsCompl(p->pCnf2->pClauses[i][0]) == (Pol & ~PolPres) ) // taking opposite literal
{
Vec_IntClear( vLits );
Vec_IntPush( vLits, toLitCond( iVarThis, Abc_LitIsCompl(p->pCnf2->pClauses[i][0]) ) );
for ( pLit = p->pCnf2->pClauses[i]+1; pLit < p->pCnf2->pClauses[i+1]; pLit++ )
{
iVar = Pdr_ObjSatVar2( p, k, Aig_ManObj(p->pAig, lit_var(*pLit)), Level+1, ((unsigned)p->pCnf2->pClaPols[i] >> (2*(pLit-p->pCnf2->pClauses[i]-1))) & 3 );
Vec_IntPush( vLits, toLitCond( iVar, lit_sign(*pLit) ) );
}
RetValue = sat_solver_addclause( pSat, Vec_IntArray(vLits), Vec_IntArray(vLits)+Vec_IntSize(vLits) );
assert( RetValue );
(void) RetValue;
}
}
clause* solver_propagate(solver* s)
{
lbool* values = s->assigns;
clause* confl = (clause*)0;
lit* lits;
/* printf("solver_propagate\n"); */
while (confl == 0 && s->qtail - s->qhead > 0){
lit p = s->trail[s->qhead++];
vecp* ws = solver_read_wlist(s,p);
clause **begin = (clause**)vecp_begin(ws);
clause **end = begin + vecp_size(ws);
clause **i, **j;
s->stats.propagations++;
s->simpdb_props--;
/* printf("checking lit %d: "L_LIT"\n", veci_size(ws),
L_lit(p)); */
for (i = j = begin; i < end; ){
if (clause_is_lit(*i)){
*j++ = *i;
if (!enqueue(s,clause_read_lit(*i),clause_from_lit(p))){
confl = s->binary;
(clause_begin(confl))[1] = lit_neg(p);
(clause_begin(confl))[0] = clause_read_lit(*i++);
/* Copy the remaining watches: */
while (i < end)
*j++ = *i++;
}
}else{
lit false_lit;
lbool sig;
lits = clause_begin(*i);
/* Make sure the false literal is data[1]: */
false_lit = lit_neg(p);
if (lits[0] == false_lit){
lits[0] = lits[1];
lits[1] = false_lit;
}
assert(lits[1] == false_lit);
/* printf("checking clause: ");
printlits(lits, lits+clause_size(*i));
printf("\n"); */
/* If 0th watch is true, then clause is already
satisfied. */
sig = !lit_sign(lits[0]); sig += sig - 1;
if (values[lit_var(lits[0])] == sig){
*j++ = *i;
}else{
/* Look for new watch: */
lit* stop = lits + clause_size(*i);
lit* k;
for (k = lits + 2; k < stop; k++){
lbool sig = lit_sign(*k); sig += sig - 1;
if (values[lit_var(*k)] != sig){
lits[1] = *k;
*k = false_lit;
vecp_push(solver_read_wlist(s,
lit_neg(lits[1])),*i);
goto next; }
}
*j++ = *i;
/* Clause is unit under assignment: */
if (!enqueue(s,lits[0], *i)){
confl = *i++;
/* Copy the remaining watches: */
while (i < end)
*j++ = *i++;
}
}
}
next:
i++;
}
s->stats.inspects += j - (clause**)vecp_begin(ws);
vecp_resize(ws,j - (clause**)vecp_begin(ws));
}
return confl;
}
static void solver_analyze(solver* s, clause* c, veci* learnt)
{
lit* trail = s->trail;
lbool* tags = s->tags;
clause** reasons = s->reasons;
int* levels = s->levels;
int cnt = 0;
lit p = lit_Undef;
int ind = s->qtail-1;
lit* lits;
int i, j, minl;
int* tagged;
veci_push(learnt,lit_Undef);
do{
assert(c != 0);
if (clause_is_lit(c)){
lit q = clause_read_lit(c);
assert(lit_var(q) >= 0 && lit_var(q) < s->size);
if (tags[lit_var(q)] == l_Undef && levels[lit_var(q)] > 0){
tags[lit_var(q)] = l_True;
veci_push(&s->tagged,lit_var(q));
act_var_bump(s,lit_var(q));
if (levels[lit_var(q)] == solver_dlevel(s))
cnt++;
else
veci_push(learnt,q);
}
}else{
if (clause_learnt(c))
act_clause_bump(s,c);
lits = clause_begin(c);
/* printlits(lits,lits+clause_size(c)); printf("\n"); */
for (j = (p == lit_Undef ? 0 : 1); j < clause_size(c); j++){
lit q = lits[j];
assert(lit_var(q) >= 0 && lit_var(q) < s->size);
if (tags[lit_var(q)] == l_Undef
&& levels[lit_var(q)] > 0){
tags[lit_var(q)] = l_True;
veci_push(&s->tagged,lit_var(q));
act_var_bump(s,lit_var(q));
if (levels[lit_var(q)] == solver_dlevel(s))
cnt++;
else
veci_push(learnt,q);
}
}
}
while (tags[lit_var(trail[ind--])] == l_Undef);
p = trail[ind+1];
c = reasons[lit_var(p)];
cnt--;
}while (cnt > 0);
*veci_begin(learnt) = lit_neg(p);
lits = veci_begin(learnt);
minl = 0;
for (i = 1; i < veci_size(learnt); i++){
int lev = levels[lit_var(lits[i])];
minl |= 1 << (lev & 31);
}
/* simplify (full) */
for (i = j = 1; i < veci_size(learnt); i++){
if (reasons[lit_var(lits[i])] == 0
|| !solver_lit_removable(s,lits[i],minl))
lits[j++] = lits[i];
}
/* update size of learnt + statistics */
s->stats.max_literals += veci_size(learnt);
veci_resize(learnt,j);
s->stats.tot_literals += j;
/* clear tags */
tagged = veci_begin(&s->tagged);
for (i = 0; i < veci_size(&s->tagged); i++)
tags[tagged[i]] = l_Undef;
veci_resize(&s->tagged,0);
#ifdef DEBUG
for (i = 0; i < s->size; i++)
assert(tags[i] == l_Undef);
#endif
#ifdef VERBOSEDEBUG
printf(L_IND"Learnt {", L_ind);
for (i = 0; i < veci_size(learnt); i++)
printf(" "L_LIT, L_lit(lits[i]));
#endif
if (veci_size(learnt) > 1){
int max_i = 1;
int max = levels[lit_var(lits[1])];
lit tmp;
for (i = 2; i < veci_size(learnt); i++)
if (levels[lit_var(lits[i])] > max){
max = levels[lit_var(lits[i])];
max_i = i;
}
tmp = lits[1];
lits[1] = lits[max_i];
lits[max_i] = tmp;
}
#ifdef VERBOSEDEBUG
{
int lev = veci_size(learnt) > 1 ? levels[lit_var(lits[1])] : 0;
printf(" } at level %d\n", lev);
}
#endif
}
static bool solver_lit_removable(solver* s, lit l, int minl)
{
lbool* tags = s->tags;
clause** reasons = s->reasons;
int* levels = s->levels;
int top = veci_size(&s->tagged);
assert(lit_var(l) >= 0 && lit_var(l) < s->size);
assert(reasons[lit_var(l)] != 0);
veci_resize(&s->stack,0);
veci_push(&s->stack,lit_var(l));
while (veci_size(&s->stack) > 0){
clause* c;
int v = veci_begin(&s->stack)[veci_size(&s->stack)-1];
assert(v >= 0 && v < s->size);
veci_resize(&s->stack,veci_size(&s->stack)-1);
assert(reasons[v] != 0);
c = reasons[v];
if (clause_is_lit(c)){
int v = lit_var(clause_read_lit(c));
if (tags[v] == l_Undef && levels[v] != 0){
if (reasons[v] != 0
&& ((1 << (levels[v] & 31)) & minl)){
veci_push(&s->stack,v);
tags[v] = l_True;
veci_push(&s->tagged,v);
}else{
int* tagged = veci_begin(&s->tagged);
int j;
for (j = top; j < veci_size(&s->tagged); j++)
tags[tagged[j]] = l_Undef;
veci_resize(&s->tagged,top);
return false;
}
}
}else{
lit* lits = clause_begin(c);
int i, j;
for (i = 1; i < clause_size(c); i++){
int v = lit_var(lits[i]);
if (tags[v] == l_Undef && levels[v] != 0){
if (reasons[v] != 0
&& ((1 << (levels[v] & 31)) & minl)){
veci_push(&s->stack,lit_var(lits[i]));
tags[v] = l_True;
veci_push(&s->tagged,v);
}else{
int* tagged = veci_begin(&s->tagged);
for (j = top; j < veci_size(&s->tagged); j++)
tags[tagged[j]] = l_Undef;
veci_resize(&s->tagged,top);
return false;
}
}
}
}
}
return true;
}
static lbool solver_search(solver* s, int nof_conflicts,
int nof_learnts)
{
int* levels = s->levels;
double var_decay = 0.95;
double clause_decay = 0.999;
double random_var_freq = 0.02;
int conflictC = 0;
veci learnt_clause;
assert(s->root_level == solver_dlevel(s));
s->stats.starts++;
s->var_decay = (float)(1 / var_decay );
s->cla_decay = (float)(1 / clause_decay);
veci_resize(&s->model,0);
veci_new(&learnt_clause);
for (;;){
clause* confl = solver_propagate(s);
if (confl != 0){
/* CONFLICT */
int blevel;
#ifdef VERBOSEDEBUG
printf(L_IND"**CONFLICT**\n", L_ind);
#endif
s->stats.conflicts++; conflictC++;
if (solver_dlevel(s) == s->root_level){
veci_delete(&learnt_clause);
return l_False;
}
veci_resize(&learnt_clause,0);
solver_analyze(s, confl, &learnt_clause);
blevel = veci_size(&learnt_clause) > 1
? levels[lit_var(veci_begin(&learnt_clause)[1])]
: s->root_level;
blevel = s->root_level > blevel ? s->root_level : blevel;
solver_canceluntil(s,blevel);
solver_record(s,&learnt_clause);
act_var_decay(s);
act_clause_decay(s);
}else{
/* NO CONFLICT */
int next;
if (nof_conflicts >= 0 && conflictC >= nof_conflicts){
/* Reached bound on number of conflicts: */
s->progress_estimate = solver_progress(s);
solver_canceluntil(s,s->root_level);
veci_delete(&learnt_clause);
return l_Undef; }
if (solver_dlevel(s) == 0)
/* Simplify the set of problem clauses: */
solver_simplify(s);
if (nof_learnts >= 0
&& vecp_size(&s->learnts) - s->qtail >= nof_learnts)
/* Reduce the set of learnt clauses: */
solver_reducedb(s);
/* New variable decision: */
s->stats.decisions++;
next = order_select(s,(float)random_var_freq);
if (next == var_Undef){
/* Model found: */
lbool* values = s->assigns;
int i;
for (i = 0; i < s->size; i++)
veci_push(&s->model,(int)values[i]);
solver_canceluntil(s,s->root_level);
veci_delete(&learnt_clause);
/*
veci apa; veci_new(&apa);
for (i = 0; i < s->size; i++)
veci_push(&apa,(int)(s->model.ptr[i] == l_True
? toLit(i) : lit_neg(toLit(i))));
printf("model: ");
printlits((lit*)apa.ptr,
(lit*)apa.ptr + veci_size(&apa)); printf("\n");
veci_delete(&apa);
*/
return l_True;
}
assume(s,lit_neg(toLit(next)));
}
}
#if 0 /* by mao; unreachable code */
return l_Undef; /* cannot happen */
#endif
}
static inline int lit_print(lit l) { return lit_sign(l)? -lit_var(l)-1 : lit_var(l)+1; }
