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forbidden intervals fixes

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This commit is contained in:
Jakob Rath 2021-09-14 10:15:10 +02:00
parent 43fef8e8ba
commit d36a658139
3 changed files with 14 additions and 5 deletions
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8
src/math/polysat/clause_builder.cpp
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@ -51,6 +51,7 @@ namespace polysat {
void clause_builder::push(signed_constraint c) { void clause_builder::push(signed_constraint c) {
SASSERT(c); SASSERT(c);
SASSERT(c->has_bvar()); SASSERT(c->has_bvar());
SASSERT(!c.is_always_true()); // clause would be a tautology
if (c->unit_clause()) { if (c->unit_clause()) {
add_dependency(c->unit_dep()); add_dependency(c->unit_dep());
m_level = std::max(m_level, c->unit_clause()->level()); m_level = std::max(m_level, c->unit_clause()->level());
@ -59,4 +60,11 @@ namespace polysat {
m_literals.push_back(c.blit()); m_literals.push_back(c.blit());
} }
void clause_builder::push_new(signed_constraint c) {
if (c.is_always_false()) // filter out trivial constraints such as "4 < 2" (may come in from forbidden intervals)
return;
if (!c->has_bvar())
m_solver->m_constraints.ensure_bvar(c.get());
push(c);
}
} }

3
src/math/polysat/clause_builder.h
View file

@ -52,6 +52,9 @@ namespace polysat {
push(i.as_signed_constraint()); push(i.as_signed_constraint());
} }
/// Push a new constraint. Allocates a boolean variable for the constraint, if necessary.
void push_new(signed_constraint c);
using const_iterator = decltype(m_literals)::const_iterator; using const_iterator = decltype(m_literals)::const_iterator;
const_iterator begin() const { return m_literals.begin(); } const_iterator begin() const { return m_literals.begin(); }
const_iterator end() const { return m_literals.end(); } const_iterator end() const { return m_literals.end(); }

8
src/math/polysat/forbidden_intervals.cpp
View file

@ -75,7 +75,7 @@ namespace polysat {
*/ */
void forbidden_intervals::full_interval_conflict(signed_constraint src, signed_constraint neg_cond, clause_builder& lemma) { void forbidden_intervals::full_interval_conflict(signed_constraint src, signed_constraint neg_cond, clause_builder& lemma) {
SASSERT(neg_cond); SASSERT(neg_cond);
lemma.push(neg_cond); lemma.push_new(neg_cond);
lemma.push(~src); lemma.push(~src);
} }
@ -158,12 +158,12 @@ namespace polysat {
// the level of a literal is when it was assigned. Lemmas could have unassigned literals. // the level of a literal is when it was assigned. Lemmas could have unassigned literals.
signed_constraint c = s.m_constraints.ult(lhs, rhs); signed_constraint c = s.m_constraints.ult(lhs, rhs);
LOG("constraint: " << c); LOG("constraint: " << c);
lemma.push(~c); lemma.push_new(~c);
// Side conditions // Side conditions
// TODO: check whether the condition is subsumed by c? maybe at the end do a "lemma reduction" step, to try and reduce branching? // TODO: check whether the condition is subsumed by c? maybe at the end do a "lemma reduction" step, to try and reduce branching?
signed_constraint& neg_cond = records[i].neg_cond; signed_constraint& neg_cond = records[i].neg_cond;
if (neg_cond) if (neg_cond)
lemma.push(std::move(neg_cond)); lemma.push_new(std::move(neg_cond));
lemma.push(~records[i].src); lemma.push(~records[i].src);
} }
@ -185,8 +185,6 @@ namespace polysat {
// Current only works when degree(v) is at most one on both sides // Current only works when degree(v) is at most one on both sides
pdd lhs = c->to_ule().lhs(); pdd lhs = c->to_ule().lhs();
pdd rhs = c->to_ule().rhs(); pdd rhs = c->to_ule().rhs();
if (!c.is_positive())
swap(lhs, rhs);
unsigned const deg1 = lhs.degree(v); unsigned const deg1 = lhs.degree(v);
unsigned const deg2 = rhs.degree(v); unsigned const deg2 = rhs.degree(v);
if (deg1 > 1 || deg2 > 1) if (deg1 > 1 || deg2 > 1)