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Check for missed boolean propagations

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This commit is contained in:
Jakob Rath 2022-12-12 11:52:45 +01:00
parent 9feefa4c0a
commit b1271ac7fb
2 changed files with 29 additions and 2 deletions
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28
src/math/polysat/solver.cpp
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@ -205,6 +205,7 @@ namespace polysat {
if (!is_conflict())
linear_propagate();
SASSERT(wlist_invariant());
SASSERT(bool_watch_invariant());
SASSERT(assignment_invariant());
}
@ -217,6 +218,7 @@ namespace polysat {
signed_constraint c = lit2cnstr(lit);
activate_constraint(c);
auto& wlist = m_bvars.watch(~lit);
LOG("wlist[" << ~lit << "]: " << wlist);
unsigned i = 0, j = 0, sz = wlist.size();
for (; i < sz && !is_conflict(); ++i)
if (!propagate(lit, *wlist[i]))
@ -1364,7 +1366,7 @@ namespace polysat {
/**
* Check that two variables of each constraint are watched.
*/
bool solver::wlist_invariant() {
bool solver::wlist_invariant() const {
#if 0
for (pvar v = 0; v < m_value.size(); ++v) {
std::stringstream s;
@ -1378,6 +1380,7 @@ namespace polysat {
for (unsigned i = m_qhead; i < m_search.size(); ++i)
if (m_search[i].is_boolean())
skip.insert(m_search[i].lit().var());
SASSERT(is_conflict() || skip.empty()); // after propagation we either finished the queue or we are in a conflict
for (auto c : m_constraints) {
if (skip.contains(c->bvar()))
continue;
@ -1403,6 +1406,29 @@ namespace polysat {
return true;
}
bool solver::bool_watch_invariant() const {
if (is_conflict()) // propagation may be unfinished if a conflict was discovered
return true;
// Check for missed boolean propagations: no clause should have exactly one unassigned literal, unless it is already true.
for (auto const& cls : m_constraints.clauses()) {
for (auto const& clref : cls) {
clause const& cl = *clref;
bool const is_true = any_of(cl, [&](auto lit) { return m_bvars.is_true(lit); });
if (is_true)
continue;
size_t const undefs = count_if(cl, [&](auto lit) { return !m_bvars.is_assigned(lit); });
if (undefs == 1) {
LOG("Missed boolean propagation of clause: " << cl);
for (sat::literal lit : cl) {
LOG(" " << lit_pp(*this, lit));
}
}
SASSERT(undefs != 1);
}
}
return true;
}
pdd solver::subst(pdd const& p) const {
return assignment().apply_to(p);
}

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

@ -303,7 +303,8 @@ namespace polysat {
bool invariant();
static bool invariant(signed_constraints const& cs);
bool wlist_invariant();
bool wlist_invariant() const;
bool bool_watch_invariant() const;
bool assignment_invariant();
bool verify_sat();