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adding Boolean propagation, watch; and factoring

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This commit is contained in:
Nikolaj Bjorner 2021-09-18 22:18:15 -04:00
parent f01da40e49
commit fa3886136b
15 changed files with 341 additions and 134 deletions
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53
src/math/polysat/constraint.cpp
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@ -55,13 +55,11 @@ namespace polysat {
m_constraints.push_back(c);
}
clause* constraint_manager::store(clause_ref cl_ref) {
clause* cl = cl_ref.get();
void constraint_manager::store(clause* cl, solver& s) {
while (m_clauses.size() <= cl->level())
m_clauses.push_back({});
m_clauses[cl->level()].push_back(std::move(cl_ref));
return cl;
m_clauses[cl->level()].push_back(cl);
watch(*cl, s);
}
void constraint_manager::register_external(signed_constraint c) {
@ -94,13 +92,48 @@ namespace polysat {
// Release constraints at the given level and above.
void constraint_manager::release_level(unsigned lvl) {
for (unsigned l = m_clauses.size(); l-- > lvl; ) {
for (auto const& cl : m_clauses[l]) {
for (auto& cl : m_clauses[l]) {
unwatch(*cl);
SASSERT_EQ(cl->m_ref_count, 1); // otherwise there is a leftover reference somewhere
}
m_clauses[l].reset();
}
}
// find literals that are not propagated to false
// if clause is unsat then assign arbitrary
// solver handles unsat clauses by creating a conflict.
// solver also can propagate, but need to check that it does indeed.
void constraint_manager::watch(clause& cl, solver& s) {
if (cl.size() <= 1)
return;
bool first = true;
for (unsigned i = 0; i < cl.size(); ++i) {
if (m_bvars.is_false(cl[i]))
continue;
m_bvars.watch(cl[i]).push_back(&cl);
std::swap(cl[!first], cl[i]);
if (!first)
return;
first = false;
}
if (first)
m_bvars.watch(cl[0]).push_back(&cl);
m_bvars.watch(cl[1]).push_back(&cl);
if (first)
s.set_conflict(cl);
else
s.propagate_bool_at(s.level(cl), cl[0], &cl);
}
void constraint_manager::unwatch(clause& cl) {
if (cl.size() <= 1)
return;
m_bvars.watch(~cl[0]).erase(&cl);
m_bvars.watch(~cl[1]).erase(&cl);
}
constraint_manager::~constraint_manager() {
// Release explicitly to check for leftover references in debug mode,
// and to make sure all constraints are destructed before the bvar->constraint mapping.
@ -219,11 +252,12 @@ namespace polysat {
return *dynamic_cast<ule_constraint const*>(this);
}
std::ostream& constraint::display_extra(std::ostream& out) const {
std::string constraint::bvar2string() const {
std::stringstream out;
out << " (b";
if (has_bvar()) { out << bvar(); } else { out << "_"; }
out << ")";
return out;
return out.str();
}
bool constraint::propagate(solver& s, bool is_positive, pvar v) {
@ -265,7 +299,8 @@ namespace polysat {
return s.m_bvars.level(bvar());
unsigned level = 0;
for (auto v : vars())
level = std::max(level, s.get_level(v));
if (s.is_assigned(v))
level = std::max(level, s.get_level(v));
return level;
}