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Polysat: refactor constraints (#5372)

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* Refactor: remove sign and dep from constraint

* fix some bugs

* improve log messages

* Add missing premises to lemma

* Rename getter in an attempt to fix linux build
This commit is contained in:
Jakob Rath 2021-06-25 20:04:25 +02:00 • committed by GitHub
parent a0b0c1f428
commit 3436b52c4a
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16 changed files with 435 additions and 325 deletions
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76
src/math/polysat/eq_constraint.cpp
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@ -19,19 +19,10 @@ Author:
namespace polysat {
std::ostream& eq_constraint::display(std::ostream& out) const {
out << p() << (sign() == pos_t ? " == 0" : " != 0");
out << p() << " == 0 ";
return display_extra(out);
}
constraint_ref eq_constraint::resolve(solver& s, pvar v) {
if (is_positive())
return eq_resolve(s, v);
if (is_negative())
return diseq_resolve(s, v);
UNREACHABLE();
return nullptr;
}
void eq_constraint::narrow(solver& s) {
SASSERT(!is_undef());
LOG("Assignment: " << assignments_pp(s));
@ -110,47 +101,36 @@ namespace polysat {
* Equality constraints
*/
constraint_ref eq_constraint::eq_resolve(solver& s, pvar v) {
LOG("Resolve " << *this << " upon v" << v);
if (s.m_conflict.size() != 1)
return nullptr;
if (!s.m_conflict.clauses().empty())
return nullptr;
constraint* c = s.m_conflict.units()[0];
SASSERT(c->is_currently_false(s));
// 'c == this' can happen if propagation was from decide() with only one value left
// (e.g., if there's an unsatisfiable clause and we try all values).
// Resolution would give us '0 == 0' in this case, which is useless.
if (c == this)
return nullptr;
SASSERT(is_currently_true(s)); // TODO: might not always hold (due to similar case as in comment above?)
if (c->is_eq() && c->is_positive()) {
pdd a = c->to_eq().p();
pdd b = p();
pdd r = a;
if (!a.resolve(v, b, r))
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 s.m_constraints.eq(lvl, pos_t, r, d);
}
return nullptr;
}
/**
* Disequality constraints
*/
constraint_ref eq_constraint::diseq_resolve(solver& s, pvar v) {
NOT_IMPLEMENTED_YET();
return nullptr;
}
// constraint_ref eq_constraint::eq_resolve(solver& s, pvar v) {
// LOG("Resolve " << *this << " upon v" << v);
// if (s.m_conflict.size() != 1)
// return nullptr;
// if (!s.m_conflict.clauses().empty())
// return nullptr;
// constraint* c = s.m_conflict.units()[0];
// SASSERT(c->is_currently_false(s));
// // 'c == this' can happen if propagation was from decide() with only one value left
// // (e.g., if there's an unsatisfiable clause and we try all values).
// // Resolution would give us '0 == 0' in this case, which is useless.
// if (c == this)
// return nullptr;
// SASSERT(is_currently_true(s)); // TODO: might not always hold (due to similar case as in comment above?)
// if (c->is_eq() && c->is_positive()) {
// pdd a = c->to_eq().p();
// pdd b = p();
// pdd r = a;
// if (!a.resolve(v, b, r))
// 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 s.m_constraints.eq(lvl, pos_t, r, d);
// }
// return nullptr;
// }
/// Compute forbidden interval for equality constraint by considering it as p <=u 0 (or p >u 0 for disequality)
bool eq_constraint::forbidden_interval(solver& s, pvar v, eval_interval& out_interval, constraint_ref& out_neg_cond)
bool eq_constraint::forbidden_interval(solver& s, pvar v, eval_interval& out_interval, constraint_literal& out_neg_cond)
{
SASSERT(!is_undef());