/*_________________________________________________________________________________________________
|
| simplify : [void] -> [bool]
|
| Description:
| Simplify the clause database according to the current top-level assigment. Currently, the only
| thing done here is the removal of satisfied clauses, but more things can be put here.
|________________________________________________________________________________________________@*/
bool MiniSATP::simplify()
{
remove_satisfied = false;
assert(decisionLevel() == 0);
// Modified Lines
// if (!ok || propagate() != NULL)
// return ok = false;
if (!ok) return false;
Clause * confl = propagate( );
if ( confl != NULL )
{
fillExplanation( confl );
return ok = false;
}
if (nAssigns() == simpDB_assigns || (simpDB_props > 0))
return true;
// Remove satisfied clauses:
removeSatisfied(learnts);
if (remove_satisfied) // Can be turned off.
removeSatisfied(clauses);
// Remove fixed variables from the variable heap:
order_heap.filter(VarFilter(*this));
simpDB_assigns = nAssigns();
simpDB_props = clauses_literals + learnts_literals; // (shouldn't depend on stats really, but it will do for now)
return true;
}
/*_________________________________________________________________________________________________
|
| simplify : [void] -> [bool]
|
| Description:
| Simplify the clause database according to the current top-level assigment. Currently, the only
| thing done here is the removal of satisfied clauses, but more things can be put here.
|________________________________________________________________________________________________@*/
bool Solver::simplify()
{
assert(decisionLevel() == 0);
if (!ok || propagate() != NULL)
return ok = false;
if (nAssigns() == simpDB_assigns || (simpDB_props > 0))
return true;
// Remove satisfied clauses:
removeSatisfied(learnts);
if (remove_satisfied) // Can be turned off.
removeSatisfied(clauses);
// Remove fixed variables from the variable heap:
order_heap.filter(VarFilter(*this));
simpDB_assigns = nAssigns();
simpDB_props = clauses_literals + learnts_literals; // (shouldn't depend on stats really, but it will do for now)
return true;
}
bool SimpSolver::eliminate(bool turn_off_elim)
{
if (!ok || !use_simplification)
return ok;
// Main simplification loop:
//assert(subsumption_queue.size() == 0);
//gatherTouchedClauses();
while (subsumption_queue.size() > 0 || elim_heap.size() > 0){
//fprintf(stderr, "subsumption phase: (%d)\n", subsumption_queue.size());
if (!backwardSubsumptionCheck(true))
return false;
//fprintf(stderr, "elimination phase:\n (%d)", elim_heap.size());
for (int cnt = 0; !elim_heap.empty(); cnt++){
Var elim = elim_heap.removeMin();
if (verbosity >= 2 && cnt % 100 == 0)
reportf("elimination left: %10d\r", elim_heap.size());
if (!frozen[elim] && !eliminateVar(elim))
return false;
}
assert(subsumption_queue.size() == 0);
gatherTouchedClauses();
}
// Cleanup:
cleanUpClauses();
order_heap.filter(VarFilter(*this));
#ifdef INVARIANTS
// Check that no more subsumption is possible:
reportf("Checking that no more subsumption is possible\n");
for (int i = 0; i < clauses.size(); i++){
if (i % 1000 == 0)
reportf("left %10d\r", clauses.size() - i);
assert(clauses[i]->mark() == 0);
for (int j = 0; j < i; j++)
assert(clauses[i]->subsumes(*clauses[j]) == lit_Error);
}
reportf("done.\n");
// Check that no more elimination is possible:
reportf("Checking that no more elimination is possible\n");
for (int i = 0; i < nVars(); i++)
if (!frozen[i]) eliminateVar(i, true);
reportf("done.\n");
checkLiteralCount();
#endif
// If no more simplification is needed, free all simplification-related data structures:
if (turn_off_elim){
use_simplification = false;
touched.clear(true);
occurs.clear(true);
n_occ.clear(true);
subsumption_queue.clear(true);
elim_heap.clear(true);
remove_satisfied = true;
}
return true;
}
