// Check if 'p' can be removed. 'abstract_levels' is used to abort early if the algorithm is
// visiting literals at levels that cannot be removed later.
bool Solver::litRedundant(Lit p, uint32_t abstract_levels)
{
analyze_stack.clear(); analyze_stack.push(p);
int top = analyze_toclear.size();
while (analyze_stack.size() > 0){
assert(reason[var(analyze_stack.last())] != NULL);
Clause& c = *reason[var(analyze_stack.last())]; analyze_stack.pop();
for (int i = 1; i < c.size(); i++){
Lit p = c[i];
if (!seen[var(p)] && level[var(p)] > 0){
if (reason[var(p)] != NULL && (abstractLevel(var(p)) & abstract_levels) != 0){
seen[var(p)] = 1;
analyze_stack.push(p);
analyze_toclear.push(p);
}else{
for (int j = top; j < analyze_toclear.size(); j++)
seen[var(analyze_toclear[j])] = 0;
analyze_toclear.shrink(analyze_toclear.size() - top);
return false;
}
}
}
}
return true;
}
/*_________________________________________________________________________________________________
|
| analyze : (confl : Clause*) (out_learnt : vec<Lit>&) (out_btlevel : int&) -> [void]
|
| Description:
| Analyze conflict and produce a reason clause.
|
| Pre-conditions:
| * 'out_learnt' is assumed to be cleared.
| * Current decision level must be greater than root level.
|
| Post-conditions:
| * 'out_learnt[0]' is the asserting literal at level 'out_btlevel'.
|
| Effect:
| Will undo part of the trail, upto but not beyond the assumption of the current decision level.
|________________________________________________________________________________________________@*/
void Solver::analyze(Clause* confl, vec<Lit>& out_learnt, int& out_btlevel,int &nbl,int &mer)
{
int pathC = 0;
Lit p = lit_Undef;
out_learnt.push(); // (leave room for the asserting literal)
int index = trail.size() - 1;
out_btlevel = 0;
do{
assert(confl != NULL); // (otherwise should be UIP)
Clause& c = *confl;
// The first one has to be SAT
if( p != lit_Undef && c.size()==2 && value(c[0])==l_False) {
assert(value(c[1])==l_True);
Lit tmp = c[0];
c[0] = c[1], c[1] = tmp;
}
for (int j = (p == lit_Undef) ? 0 : 1; j < c.size(); j++){
Lit q = c[j];
if (!seen[var(q)] && level[var(q)] > 0){
varBumpActivity(var(q));
seen[var(q)] = 1;
if (level[var(q)] >= decisionLevel()){
pathC++;
#ifdef UPDATEVARACTIVITY
if((reason[var(q)]!=NULL) && (reason[var(q)]->learnt()))
lastDecisionLevel.push(q);
#endif
}
else{
out_learnt.push(q);
if (level[var(q)] > out_btlevel)
out_btlevel = level[var(q)];
}
}
}
// Select next clause to look at:
while (!seen[var(trail[index--])]);
p = trail[index+1];
confl = reason[var(p)];
seen[var(p)] = 0;
pathC--;
}while (pathC > 0);
out_learnt[0] = ~p;
// Simplify conflict clause:
//
int i, j;
if (expensive_ccmin){
uint32_t abstract_level = 0;
for (i = 1; i < out_learnt.size(); i++)
abstract_level |= abstractLevel(var(out_learnt[i])); // (maintain an abstraction of levels involved in conflict)
out_learnt.copyTo(analyze_toclear);
for (i = j = 1; i < out_learnt.size(); i++)
if (reason[var(out_learnt[i])] == NULL || !litRedundant(out_learnt[i], abstract_level))
out_learnt[j++] = out_learnt[i];
}else{
out_learnt.copyTo(analyze_toclear);
for (i = j = 1; i < out_learnt.size(); i++){
Clause& c = *reason[var(out_learnt[i])];
if(c.size()==2 && value(c[0])==l_False) {
assert(value(c[1])==l_True);
Lit tmp = c[0];
c[0] = c[1], c[1] = tmp;
}
for (int k = 1; k < c.size(); k++)
if (!seen[var(c[k])] && level[var(c[k])] > 0){
out_learnt[j++] = out_learnt[i];
break; }
}
}
max_literals += out_learnt.size();
out_learnt.shrink(i - j);
tot_literals += out_learnt.size();
// Find correct backtrack level:
//
if (out_learnt.size() == 1)
out_btlevel = 0;
else{
int max_i = 1;
for (int i = 2; i < out_learnt.size(); i++)
if (level[var(out_learnt[i])] > level[var(out_learnt[max_i])])
max_i = i;
Lit p = out_learnt[max_i];
out_learnt[max_i] = out_learnt[1];
out_learnt[1] = p;
out_btlevel = level[var(p)];
}
nbl = 0;mer = 0;
MYFLAG++;
for(int i=0;i<out_learnt.size();i++) {
int l = level[var(out_learnt[i])];
if (permDiff[l] != MYFLAG) {
permDiff[l] = MYFLAG;
nbl++;
mer +=nbPropagated(l);
}
}
#ifdef UPDATEVARACTIVITY
if(lastDecisionLevel.size()>0) {
for(int i = 0;i<lastDecisionLevel.size();i++) {
if(reason[var(lastDecisionLevel[i])]->activity()<nbl)
varBumpActivity(var(lastDecisionLevel[i]));
}
lastDecisionLevel.clear();
}
#endif
for (int j = 0; j < analyze_toclear.size(); j++) seen[var(analyze_toclear[j])] = 0; // ('seen[]' is now cleared)
}
/*_________________________________________________________________________________________________
|
| analyze : (confl : Clause*) (out_learnt : vec<Lit>&) (out_btlevel : int&) -> [void]
|
| Description:
| Analyze conflict and produce a reason clause.
|
| Pre-conditions:
| * 'out_learnt' is assumed to be cleared.
| * Current decision level must be greater than root level.
|
| Post-conditions:
| * 'out_learnt[0]' is the asserting literal at level 'out_btlevel'.
|
| Effect:
| Will undo part of the trail, upto but not beyond the assumption of the current decision level.
|________________________________________________________________________________________________@*/
void Solver::analyze(Clause* confl, vec<Lit>& out_learnt, int& out_btlevel)
{
int pathC = 0;
Lit p = lit_Undef;
// Generate conflict clause:
//
out_learnt.push(); // (leave room for the asserting literal)
int index = trail.size() - 1;
out_btlevel = 0;
do{
assert(confl != NULL); // (otherwise should be UIP)
Clause& c = *confl;
if (c.learnt())
claBumpActivity(c);
for (int j = (p == lit_Undef) ? 0 : 1; j < c.size(); j++){
Lit q = c[j];
if (!seen[var(q)] && level[var(q)] > 0){
varBumpActivity(var(q));
seen[var(q)] = 1;
if (level[var(q)] >= decisionLevel())
pathC++;
else{
out_learnt.push(q);
if (level[var(q)] > out_btlevel)
out_btlevel = level[var(q)];
}
}
}
// Select next clause to look at:
while (!seen[var(trail[index--])]);
p = trail[index+1];
confl = reason[var(p)];
seen[var(p)] = 0;
pathC--;
}while (pathC > 0);
out_learnt[0] = ~p;
// Simplify conflict clause:
//
int i, j;
if (expensive_ccmin){
uint32_t abstract_level = 0;
for (i = 1; i < out_learnt.size(); i++)
abstract_level |= abstractLevel(var(out_learnt[i])); // (maintain an abstraction of levels involved in conflict)
out_learnt.copyTo(analyze_toclear);
for (i = j = 1; i < out_learnt.size(); i++)
if (reason[var(out_learnt[i])] == NULL || !litRedundant(out_learnt[i], abstract_level))
out_learnt[j++] = out_learnt[i];
}else{
out_learnt.copyTo(analyze_toclear);
for (i = j = 1; i < out_learnt.size(); i++){
Clause& c = *reason[var(out_learnt[i])];
for (int k = 1; k < c.size(); k++)
if (!seen[var(c[k])] && level[var(c[k])] > 0){
out_learnt[j++] = out_learnt[i];
break; }
}
}
max_literals += out_learnt.size();
out_learnt.shrink(i - j);
tot_literals += out_learnt.size();
// Find correct backtrack level:
//
if (out_learnt.size() == 1)
out_btlevel = init_level;
else{
int max_i = 1;
for (int i = 2; i < out_learnt.size(); i++)
if (level[var(out_learnt[i])] > level[var(out_learnt[max_i])])
max_i = i;
Lit p = out_learnt[max_i];
out_learnt[max_i] = out_learnt[1];
out_learnt[1] = p;
out_btlevel = level[var(p)];
}
for (int j = 0; j < analyze_toclear.size(); j++) seen[var(analyze_toclear[j])] = 0; // ('seen[]' is now cleared)
}
/*_________________________________________________________________________________________________
|
| analyze : (confl : Clause*) (out_learnt : vec<Lit>&) (out_btlevel : int&) -> [void]
|
| Description:
| Analyze conflict and produce a reason clause.
|
| Pre-conditions:
| * 'out_learnt' is assumed to be cleared.
| * Current decision level must be greater than root level.
|
| Post-conditions:
| * 'out_learnt[0]' is the asserting literal at level 'out_btlevel'.
|
| Effect:
| Will undo part of the trail, upto but not beyond the assumption of the current decision level.
|________________________________________________________________________________________________@*/
void Solver::analyze(Clause* confl, vec<Lit>& out_learnt, int& out_btlevel)
{
int pathC = 0;
Lit p = lit_Undef;
// Generate conflict clause:
//
out_learnt.push(); // (leave room for the asserting literal)
int index = trail.size() - 1;
out_btlevel = 0;
do{
Clause& c = *confl;
#ifdef __PRINT
printf("Explain: ");
printClause(c);
printf("\n");
#endif
if (c.learnt())
claBumpActivity(c);
for (int j = (p == lit_Undef) ? 0 : 1; j < c.size(); j++){
Lit q = c[j];
if (!seen[var(q)] && level[var(q)] > 0){
#ifdef _MINISAT_DEFAULT_VSS
varBumpActivity(var(q));
#endif
seen[var(q)] = 1;
if (level[var(q)] >= decisionLevel()) {
pathC++;
}else{
out_learnt.push(q);
if (level[var(q)] > out_btlevel)
out_btlevel = level[var(q)];
}
}
}
// Select next clause to look at:
while (!seen[var(trail[index--])]);
p = trail[index+1];
confl = reason[var(p)];
seen[var(p)] = 0;
pathC--;
} while (pathC > 0);
out_learnt[0] = ~p;
// Simplify conflict clause:
//
int i, j;
if (expensive_ccmin){
uint32_t abstract_level = 0;
for (i = 1; i < out_learnt.size(); i++)
abstract_level |= abstractLevel(var(out_learnt[i])); // (maintain an abstraction of levels involved in conflict)
out_learnt.copyTo(analyze_toclear);
for (i = j = 1; i < out_learnt.size(); i++)
if (reason[var(out_learnt[i])] == NULL || !litRedundant(out_learnt[i], abstract_level))
out_learnt[j++] = out_learnt[i];
}else{
out_learnt.copyTo(analyze_toclear);
for (i = j = 1; i < out_learnt.size(); i++){
Clause& c = *reason[var(out_learnt[i])];
for (int k = 1; k < c.size(); k++)
if (!seen[var(c[k])] && level[var(c[k])] > 0){
out_learnt[j++] = out_learnt[i];
break; }
}
}
max_literals += out_learnt.size();
out_learnt.shrink(i - j);
tot_literals += out_learnt.size();
// Find correct backtrack level:
//
if (out_learnt.size() == 1)
out_btlevel = 0;
else{
int max_i = 1;
for (int i = 2; i < out_learnt.size(); i++)
if (level[var(out_learnt[i])] > level[var(out_learnt[max_i])])
max_i = i;
Lit p = out_learnt[max_i];
out_learnt[max_i] = out_learnt[1];
out_learnt[1] = p;
out_btlevel = level[var(p)];
}
#ifdef __PRINT
printf("Learnt: ");
for (int i = 0; i < out_learnt.size(); i++) {
printf("%s%d ", sign(out_learnt[i]) ? "-" : "", var(out_learnt[i]));
if (value(out_learnt[i]) != l_False)
exit(1);
}
printf("\n");
#endif
for (int j = 0; j < analyze_toclear.size(); j++) seen[var(analyze_toclear[j])] = 0; // ('seen[]' is now cleared)
}
