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fix conflict reset condition

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This commit is contained in:
Jakob Rath 2023-03-23 09:29:38 +01:00
parent 4e9db7c4d9
commit 51025a75b4
3 changed files with 42 additions and 9 deletions
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17
src/math/polysat/conflict.cpp
View file

@ -192,6 +192,7 @@ namespace polysat {
}
unsigned conflict::effective_level() const {
SASSERT(!empty());
// If m_dep is set, the corresponding constraint was asserted at m_level and is not valid earlier.
if (m_dep != null_dependency)
return m_level;
@ -207,6 +208,22 @@ namespace polysat {
return lvl;
}
bool conflict::is_valid() const {
SASSERT(!empty());
// If m_dep is set, the corresponding constraint was asserted at m_level and is not valid earlier.
if (m_dep != null_dependency)
return m_level <= s.m_level;
// All conflict constraints must be bool-assigned.
for (unsigned lit_idx : m_literals)
if (!s.m_bvars.is_assigned(sat::to_literal(lit_idx)))
return false;
// All conflict variables must be assigned.
for (pvar v : m_vars)
if (!s.is_assigned(v))
return false;
return true;
}
void conflict::init_at_base_level(dependency dep) {
SASSERT(empty());
SASSERT(s.at_base_level());

1
src/math/polysat/conflict.h
View file

@ -123,6 +123,7 @@ namespace polysat {
unsigned level() const { return m_level; }
unsigned effective_level() const;
bool is_valid() const; // TODO: better name?
bool is_relevant_pvar(pvar v) const;
bool is_relevant(sat::literal lit) const;

33
src/math/polysat/solver.cpp
View file

@ -1439,20 +1439,35 @@ namespace polysat {
unsigned const base_level = m_base_levels[m_base_levels.size() - num_scopes];
unsigned const target_level = base_level - 1;
clause_ref_vector lemmas;
if (is_conflict() && target_level < m_conflict.effective_level()) {
lemmas = m_conflict.take_lemmas();
m_conflict.reset();
// TODO: effective_level is the wrong measure (or rather, we would need additional work to be able to keep the conflict).
// we should compare m_search index. Alternatively, simply check if pop_levels unassigned any relevant element.
// clause_ref_vector lemmas;
// if (is_conflict() && target_level < m_conflict.effective_level()) {
// lemmas = m_conflict.take_lemmas();
// m_conflict.reset();
// }
if (is_conflict()) {
for (signed_constraint c : m_conflict) {
VERIFY(m_bvars.is_assigned(c.blit()));
}
for (pvar v : m_conflict.vars()) {
VERIFY(is_assigned(v));
}
VERIFY(m_conflict.is_valid());
}
pop_levels(m_level - base_level + 1);
SASSERT_EQ(m_level, target_level);
// TODO: currently we forget all new lemmas at this point.
// (but anything that uses popped assumptions cannot be used anymore.)
for (clause* lemma : lemmas)
if (lemma->is_active())
propagate_clause(*lemma);
if (is_conflict() && !m_conflict.is_valid()) {
clause_ref_vector lemmas = m_conflict.take_lemmas();
m_conflict.reset();
// TODO: currently we forget all new lemmas at this point.
// (but anything that uses popped assumptions cannot be used anymore.)
for (clause* lemma : lemmas)
if (lemma->is_active())
propagate_clause(*lemma);
}
m_base_levels.shrink(m_base_levels.size() - num_scopes);
m_base_index.shrink(m_base_index.size() - num_scopes);