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Separate constraint creation from activation; add sign/polarity to constraints (#5217)

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* Separate constraint creation from activation

* Basic recursive handling of disjunctive lemmas for unit tests

* Set learned constraint to true immediately

* Preliminary support for negated constraints
This commit is contained in:
Jakob Rath 2021-04-26 18:55:58 +02:00 • committed by GitHub
parent 2fac9e6e66
commit 9e505d60f0
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GPG key ID: 4AEE18F83AFDEB23
12 changed files with 244 additions and 73 deletions
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69
src/math/polysat/eq_constraint.cpp
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@ -19,7 +19,7 @@ Author:
namespace polysat {
std::ostream& eq_constraint::display(std::ostream& out) const {
return out << p() << " == 0";
return out << p() << (sign() == pos_t ? " == 0" : " != 0") << " [" << m_status << "]";
}
bool eq_constraint::propagate(solver& s, pvar v) {
@ -43,9 +43,56 @@ namespace polysat {
}
constraint* eq_constraint::resolve(solver& s, pvar v) {
if (is_positive())
return eq_resolve(s, v);
if (is_negative())
return diseq_resolve(s, v);
UNREACHABLE();
}
void eq_constraint::narrow(solver& s) {
if (is_positive())
eq_narrow(s);
if (is_negative())
diseq_narrow(s);
}
bool eq_constraint::is_always_false() {
if (is_positive())
return p().is_never_zero();
if (is_negative())
return p().is_zero();
UNREACHABLE();
}
bool eq_constraint::is_currently_false(solver& s) {
pdd r = p().subst_val(s.m_search);
if (is_positive())
return r.is_never_zero();
if (is_negative())
return r.is_zero();
UNREACHABLE();
}
bool eq_constraint::is_currently_true(solver& s) {
pdd r = p().subst_val(s.m_search);
if (is_positive())
return r.is_zero();
if (is_negative())
return r.is_never_zero();
UNREACHABLE();
}
/**
* Equality constraints
*/
constraint* eq_constraint::eq_resolve(solver& s, pvar v) {
SASSERT(is_currently_true(s));
if (s.m_conflict.size() != 1)
return nullptr;
constraint* c = s.m_conflict[0];
SASSERT(c->is_currently_false(s));
if (c->is_eq()) {
pdd a = c->to_eq().p();
pdd b = p();
@ -54,12 +101,14 @@ namespace polysat {
return nullptr;
p_dependency_ref d(s.m_dm.mk_join(c->dep(), dep()), s.m_dm);
unsigned lvl = std::max(c->level(), level());
return constraint::eq(lvl, r, d);
constraint* lemma = constraint::eq(lvl, s.m_next_bvar++, pos_t, r, d);
lemma->assign_eh(true);
return lemma;
}
return nullptr;
}
void eq_constraint::narrow(solver& s) {
void eq_constraint::eq_narrow(solver& s) {
LOG("Assignment: " << s.m_search);
auto q = p().subst_val(s.m_search);
LOG("Substituted: " << p() << " := " << q);
@ -92,13 +141,17 @@ namespace polysat {
// TODO: what other constraints can be extracted cheaply?
}
bool eq_constraint::is_always_false() {
return p().is_never_zero();
/**
* Disequality constraints
*/
constraint* eq_constraint::diseq_resolve(solver& s, pvar v) {
NOT_IMPLEMENTED_YET();
}
bool eq_constraint::is_currently_false(solver& s) {
pdd r = p().subst_val(s.m_search);
return r.is_never_zero();
void eq_constraint::diseq_narrow(solver& s) {
NOT_IMPLEMENTED_YET();
}
}