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Polysat: add two more prototype rules (#5355)

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* Add try_div to PDDs

* x>y is false when x==y

* First version of the other two prototype rules

* More band-aid fixes...
This commit is contained in:
Jakob Rath 2021-06-18 17:48:50 +02:00 • committed by GitHub
parent 3e1cfcd538
commit c4963f4381
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GPG key ID: 4AEE18F83AFDEB23
7 changed files with 239 additions and 17 deletions
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19
src/math/polysat/solver.cpp
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@ -121,6 +121,7 @@ namespace polysat {
LOG("Starting");
m_disjunctive_lemma.reset();
while (m_lim.inc()) {
m_stats.m_num_iterations++;
LOG_H1("Next solving loop iteration");
LOG("Free variables: " << m_free_vars);
LOG("Assignments: " << assignment());
@ -622,6 +623,10 @@ namespace polysat {
}
SASSERT(m_bvars.is_propagation(var));
clause_ref new_lemma = resolve_bool(lit);
if (!new_lemma) {
backtrack(i, lemma);
return;
}
SASSERT(new_lemma);
LOG("new_lemma: " << show_deref(new_lemma));
LOG("new_lemma is always false: " << new_lemma->is_always_false(*this));
@ -905,6 +910,7 @@ namespace polysat {
// - We have a conflict but we don't know. It will be discovered when y and z are assigned,
// and then may lead to an assertion failure through this call to narrow.
// TODO: what to do with "unassigned" constraints at this point? (we probably should have resolved those away, even in the 'backtrack' case.)
// NOTE: they are constraints from clauses that were added to cjust… how to deal with that? should we add the whole clause to cjust?
if (!c->is_undef()) // TODO: this check to be removed once this is fixed properly.
c->narrow(*this);
if (is_conflict()) {
@ -963,6 +969,8 @@ namespace polysat {
for (auto c : m_conflict.units()) {
if (c->bvar() == var)
continue;
if (c->is_undef()) // TODO: see revert_decision for a note on this.
continue;
reason_lvl = std::max(reason_lvl, c->level());
reason_dep = m_dm.mk_join(reason_dep, c->dep());
reason_lits.push_back(c->blit());
@ -981,13 +989,23 @@ namespace polysat {
continue;
// NOTE: in general, narrow may change the conflict.
// But since we just backjumped, narrowing should not result in an additional conflict.
if (c->is_undef()) // TODO: see revert_decision for a note on this.
continue;
c->narrow(*this);
if (is_conflict()) {
LOG_H1("Conflict during revert_bool_decision/narrow!");
return;
}
}
m_conflict.reset();
clause* reason_cl = reason.get();
add_lemma_clause(std::move(reason));
propagate_bool(~lit, reason_cl);
if (is_conflict()) {
LOG_H1("Conflict during revert_bool_decision/propagate_bool!");
return;
}
decide_bool(*lemma);
}
@ -1202,6 +1220,7 @@ namespace polysat {
}
void solver::collect_statistics(statistics& st) const {
st.update("polysat iterations", m_stats.m_num_iterations);
st.update("polysat decisions", m_stats.m_num_decisions);
st.update("polysat conflicts", m_stats.m_num_conflicts);
st.update("polysat propagations", m_stats.m_num_propagations);