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Expand always-false check

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This commit is contained in:
Jakob Rath 2022-09-28 10:57:40 +02:00
parent 27b31c88d2
commit e08e124790
3 changed files with 11 additions and 5 deletions
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1
src/math/polysat/solver.cpp
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@ -196,6 +196,7 @@ namespace polysat {
break;
case l_undef:
if (c.is_always_false()) {
LOG("Always false: " << c);
// asserted an always-false constraint
set_conflict_at_base_level();
return;

13
src/math/polysat/ule_constraint.cpp
View file

@ -134,17 +134,22 @@ namespace polysat {
s.m_viable.intersect(p, q, sc);
}
bool ule_constraint::is_always_false(bool is_positive, pdd const& lhs, pdd const& rhs) const {
// TODO: other conditions (e.g. when forbidden interval would be full)
bool ule_constraint::is_always_false(bool is_positive, pdd const& lhs, pdd const& rhs) {
if (is_positive) {
// lhs <= rhs
if (rhs.is_zero())
return lhs.is_never_zero();
return lhs.is_never_zero(); // p <= 0 implies p == 0
return lhs.is_val() && rhs.is_val() && lhs.val() > rhs.val();
}
else {
// lhs > rhs
if (lhs.is_zero())
return true; // 0 > ... is always false
return (lhs.is_val() && rhs.is_val() && lhs.val() <= rhs.val()) || (lhs == rhs);
if (lhs == rhs)
return true; // p > p
if (lhs.is_one() && rhs.is_never_zero())
return true; // 1 > p implies p == 0
return lhs.is_val() && rhs.is_val() && lhs.val() <= rhs.val();
}
}

2
src/math/polysat/ule_constraint.h
View file

@ -34,7 +34,7 @@ namespace polysat {
pdd const& rhs() const { return m_rhs; }
std::ostream& display(std::ostream& out, lbool status) const override;
std::ostream& display(std::ostream& out) const override;
bool is_always_false(bool is_positive, pdd const& lhs, pdd const& rhs) const;
static bool is_always_false(bool is_positive, pdd const& lhs, pdd const& rhs);
bool is_always_false(bool is_positive) const override;
bool is_currently_false(solver& s, bool is_positive) const override;
bool is_currently_true(solver& s, bool is_positive) const override;