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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2021-07-02 02:48:45 -07:00
parent 05bcf0bed7
commit 788de7d614
9 changed files with 174 additions and 45 deletions
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60
src/math/polysat/explain.cpp
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@ -39,7 +39,7 @@ namespace polysat {
if (!c->is_undef())
m_conflict.push_back(c);
for (auto* c : confl.clauses())
m_conflict.push_back(c);
m_conflict.push_back(c);
// TODO: we should share work done for examining constraints between different resolution methods
clause_ref lemma;
@ -81,16 +81,58 @@ namespace polysat {
return lemma;
}
/**
* Polynomial superposition.
* So far between two equalities.
* TODO: Also handle =, != superposition here?
* TODO: handle case when m_conflict.units().size() > 2
* TODO: handle super-position into a clause?
*/
clause_ref conflict_explainer::by_polynomial_superposition() {
if (m_conflict.units().size() != 2 || m_conflict.clauses().size() > 0)
LOG_H3("units-size: " << m_conflict.units().size() << " conflict-clauses " << m_conflict.clauses().size());
constraint* c1 = nullptr, *c2 = nullptr;
if (m_conflict.units().size() == 2 && m_conflict.clauses().size() == 0) {
c1 = m_conflict.units()[0];
c2 = m_conflict.units()[1];
}
else {
// other combinations?
#if 0
// A clause can also be a unit.
// Even if a clause is not a unit, we could still resolve a propagation
// into some literal in the current conflict clause.
// Selecting resolvents should not be specific to superposition.
//
for (auto clause : m_conflict.clauses()) {
if (clause->size() == 1) {
sat::literal lit = (*clause)[0];
if (lit.sign())
continue;
constraint* c = m_solver.m_constraints.lookup(lit.var());
LOG("unit clause: " << *c);
if (c->is_eq() && c->is_positive()) {
c1 = c;
break;
}
}
}
if (!c1)
return nullptr;
for (constraint* c : m_conflict.units()) {
if (c->is_eq() && c->is_positive()) {
c2 = c;
break;
}
}
std::cout << c1 << " " << c2 << "\n";
#endif
}
if (!c1 || !c2 || c1 == c2)
return nullptr;
constraint* c1 = m_conflict.units()[0];
constraint* c2 = m_conflict.units()[1];
if (c1 == c2)
return nullptr;
if (!c1->is_eq() || !c2->is_eq())
return nullptr;
if (c1->is_positive() && c2->is_positive()) {
if (c1->is_eq() && c2->is_eq() && c1->is_positive() && c2->is_positive()) {
pdd a = c1->to_eq().p();
pdd b = c2->to_eq().p();
pdd r = a;