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This commit is contained in:
Jakob Rath 2021-09-10 14:19:39 +02:00
parent 2b6ae0070f
commit 8a1a202133
4 changed files with 20 additions and 14 deletions
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5
src/math/polysat/conflict_core.cpp
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@ -80,7 +80,7 @@ namespace polysat {
void conflict_core::insert(signed_constraint c) {
SASSERT(!empty()); // should use set() to enter conflict state
LOG("inserting:" << c);
LOG("inserting: " << c);
// Skip trivial constraints
// (e.g., constant ones such as "4 > 1"... only true ones should appear, otherwise the lemma would be a tautology)
if (c.is_always_true())
@ -156,7 +156,10 @@ namespace polysat {
auto& premises = it->m_value;
clause_builder c_lemma(*m_solver);
for (auto premise : premises) {
cm().ensure_bvar(premise.get());
// keep(premise);
handle_saturation_premises(premise);
SASSERT(premise->has_bvar());
c_lemma.push(~premise.blit());
active_level = std::max(active_level, m_solver->m_bvars.level(premise.blit()));
}

1
src/math/polysat/explain.cpp
View file

@ -35,6 +35,7 @@ namespace polysat {
// (this condition might be too strict, but we use it for now to prevent looping)
if (b.degree(v) <= r.degree(v))
return {};
SASSERT(r.degree(v) < b.degree(v));
unsigned const lvl = std::max(c1->level(), c2->level());
signed_constraint c = cm().eq(lvl, r);
LOG("resolved: " << c << " currently false? " << c.is_currently_false(s()));

23
src/math/polysat/solver.cpp
View file

@ -455,6 +455,8 @@ namespace polysat {
LOG_H2("Resolve conflict");
LOG("\n" << *this);
LOG("search state: " << m_search);
for (pvar v = 0; v < m_cjust.size(); ++v)
LOG("cjust[v" << v << "]: " << m_cjust[v]);
++m_stats.m_num_conflicts;
SASSERT(is_conflict());
@ -629,17 +631,9 @@ namespace polysat {
backjump(lvl - 1);
// TODO: we need to decide_bool on the clause (learn_lemma takes care of this).
// if the lemma was asserting, then this will propagate the last literal. otherwise we do the enumerative guessing as normal.
// we need to exclude the current value of v. narrowing of the guessed constraint *should* take care of it but we cannot count on that.
// TODO: what do we add as 'cjust' for this restriction? the guessed
// constraint from the lemma should be the right choice. but, how to
// carry this over when the guess is reverted? need to remember the
// variable 'v' somewhere on the lemma.
// the restriction v /= val can live before the guess... (probably should ensure that the guess stays close to the current position in the stack to prevent confusion...)
// The justification for this restriction is the guessed constraint from the lemma.
// cjust[v] will be updated accordingly by decide_bool.
m_viable.add_non_viable(v, val);
learn_lemma(v, std::move(lemma));
if (is_conflict()) {
@ -788,8 +782,13 @@ namespace polysat {
if (!lemma)
return;
LOG("Lemma: " << show_deref(lemma));
for (sat::literal l : *lemma)
LOG(" Literal " << l << " is: " << m_constraints.lookup(l));
for (sat::literal lit : *lemma) {
LOG(" Literal " << lit << " is: " << m_constraints.lookup(lit));
// TODO: fully evaluated constraints must be put onto the stack as propagations.
signed_constraint c = m_constraints.lookup(lit);
SASSERT(m_bvars.is_assigned(lit) && !c.is_currently_false(*this));
SASSERT(m_bvars.is_assigned(lit) && !c.is_currently_true(*this));
}
SASSERT(lemma->size() > 0);
clause* cl = m_constraints.store(std::move(lemma));
m_redundant_clauses.push_back(cl);

5
src/math/polysat/ule_constraint.cpp
View file

@ -110,8 +110,11 @@ namespace polysat {
bool ule_constraint::is_currently_true(solver& s, bool is_positive) {
auto p = lhs().subst_val(s.assignment());
auto q = rhs().subst_val(s.assignment());
if (is_positive)
if (is_positive) {
if (p.is_zero())
return true;
return p.is_val() && q.is_val() && p.val() <= q.val();
}
else
return p.is_val() && q.is_val() && p.val() > q.val();
}