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Polysat: conflict explanation prototype (#5353)

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* display constraint's extra info in one place

* Add stub for conflict explainer

* Add helper functions to check whether constraint is active at base level

* Add helper class tmp_assign

* Add clause_builder; it skips unnecessary literals during clause creation

* some fixes

* Use clause_builder for forbidden intervals

* remove old comments

* fixes/comments in solver

* print redundant clauses

* First pass at conflict_explainer

* remove unused model class

* Choose value for k

* also print min/max k
This commit is contained in:
Jakob Rath 2021-06-17 17:35:32 +02:00 • committed by GitHub
parent 1fe7dc40fe
commit 3e1cfcd538
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GPG key ID: 4AEE18F83AFDEB23
11 changed files with 449 additions and 60 deletions
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40
src/math/polysat/constraint.cpp
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@ -154,6 +154,13 @@ namespace polysat {
return ult(lvl, sign, a + shift, b + shift, d);
}
std::ostream& constraint::display_extra(std::ostream& out) const {
out << " @" << level() << " (b" << bvar() << ")";
if (is_undef())
out << " [inactive]";
return out;
}
bool constraint::propagate(solver& s, pvar v) {
LOG_H3("Propagate " << s.m_vars[v] << " in " << *this);
SASSERT(!vars().empty());
@ -194,12 +201,13 @@ namespace polysat {
}
clause_ref clause::from_literals(unsigned lvl, p_dependency_ref const& d, sat::literal_vector literals, constraint_ref_vector constraints) {
return alloc(clause, lvl, d, literals, constraints);
return alloc(clause, lvl, d, std::move(literals), std::move(constraints));
}
bool clause::is_always_false(solver& s) const {
return std::all_of(m_literals.begin(), m_literals.end(), [&s](sat::literal lit) {
constraint *c = s.m_constraints.lookup(lit.var());
tmp_assign _t(c, lit);
return c->is_always_false();
});
}
@ -207,6 +215,7 @@ namespace polysat {
bool clause::is_currently_false(solver& s) const {
return std::all_of(m_literals.begin(), m_literals.end(), [&s](sat::literal lit) {
constraint *c = s.m_constraints.lookup(lit.var());
tmp_assign _t(c, lit);
return c->is_currently_false(s);
});
}
@ -247,6 +256,35 @@ namespace polysat {
return out;
}
void clause_builder::reset() {
m_literals.reset();
m_new_constraints.reset();
SASSERT(empty());
}
clause_ref clause_builder::build(unsigned lvl, p_dependency_ref const& d) {
clause_ref cl = clause::from_literals(lvl, d, std::move(m_literals), std::move(m_new_constraints));
SASSERT(empty());
return cl;
}
void clause_builder::push_literal(sat::literal lit) {
if (m_solver.active_at_base_level(lit))
return;
m_literals.push_back(lit);
}
void clause_builder::push_new_constraint(constraint_ref c) {
SASSERT(c);
SASSERT(c->is_undef());
sat::literal lit{c->bvar()};
tmp_assign _t(c, lit);
if (c->is_always_false())
return;
m_literals.push_back(lit);
m_new_constraints.push_back(std::move(c));
}
std::ostream& constraints_and_clauses::display(std::ostream& out) const {
bool first = true;
for (auto c : units()) {