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handle empty clauses created as lemmas as unsat state.

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add unit tests
This commit is contained in:
Nikolaj Bjorner 2021-09-19 15:43:47 -04:00
parent c69c316b27
commit 1e3ff3179e
10 changed files with 113 additions and 80 deletions
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24
src/math/polysat/solver.cpp
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@ -57,7 +57,7 @@ namespace polysat {
(m_stats.m_num_decisions < m_max_decisions);
}
lbool solver::check_sat() {
lbool solver::check_sat() {
LOG("Starting");
while (inc()) {
m_stats.m_num_iterations++;
@ -520,7 +520,7 @@ namespace polysat {
LOG_H3("resolve_bool: " << lit << " " << other);
m_conflict.resolve(m_constraints, var, other);
}
void solver::report_unsat() {
backjump(base_level());
SASSERT(!m_conflict.empty());
@ -565,9 +565,11 @@ namespace polysat {
return;
case l_false:
continue;
default:
if (lit2cnstr(lit).is_currently_false(*this))
default:
if (lit2cnstr(lit).is_currently_false(*this)) {
num_choices++;
continue;
}
break;
}
num_choices++;
@ -601,6 +603,10 @@ namespace polysat {
SASSERT(m_justification[v].is_decision());
clause_ref lemma = m_conflict.build_lemma().build();
if (lemma->empty()) {
report_unsat();
return;
}
m_conflict.reset();
backjump(get_level(v) - 1);
@ -644,7 +650,7 @@ namespace polysat {
// again L is in core, unless we core-reduced it away
clause_builder reason_builder = m_conflict.build_lemma();
m_conflict.reset();
bool contains_lit = std::find(reason_builder.begin(), reason_builder.end(), ~lit);
if (!contains_lit) {
@ -662,6 +668,12 @@ namespace polysat {
}
clause_ref reason = reason_builder.build();
if (reason->empty()) {
report_unsat();
return;
}
m_conflict.reset();
std::cout << "reason " << *reason << "\n";
// The lemma where 'lit' comes from.
@ -751,6 +763,8 @@ namespace polysat {
LOG(" Literal " << lit << " is: " << lit2cnstr(lit));
SASSERT(m_bvars.value(lit) != l_true);
}
if (lemma.empty())
std::cout << lemma << "\n";
SASSERT(!lemma.empty());
m_constraints.store(&lemma, *this);
if (lemma.size() == 1) {