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This commit is contained in:
Jakob Rath 2022-12-13 11:49:54 +01:00
parent a3c7a869cd
commit 519ebd8a8b
1 changed files with 10 additions and 2 deletions
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12
src/math/polysat/solver.cpp
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@ -533,13 +533,15 @@ namespace polysat {
using T = std::decay_t<decltype(arg)>;
if constexpr (std::is_same_v<T, sat::literal>) {
sat::literal lit = arg;
m_search.push_boolean(arg);
m_search.push_boolean(lit);
m_trail.push_back(trail_instr_t::assign_bool_i);
LOG("Replay: " << lit);
}
else if constexpr (std::is_same_v<T, pvar>) {
pvar v = arg;
m_search.push_assignment(v, m_value[v]);
m_trail.push_back(trail_instr_t::assign_i);
LOG("Replay: " << assignment_pp(*this, v, m_value[v]));
// TODO: are the viable sets propagated properly?
// when substituting polynomials, it will now take into account the replayed variables, which may itself depend on previous propagations.
// will we get into trouble with cyclic dependencies?
@ -553,6 +555,12 @@ namespace polysat {
// then we get an assignment up to that dependency level.
// each literal can only depend on entries with lower dependency level
// (that is the invariant that propagations are justified by a prefix of the search stack.)
// Actually, cyclic dependencies probably don't happen:
// - viable restrictions only occur when all-but-one variable is set (or some vars are irrelevant... those might introduce additional fake dependencies)
// - we only replay propagations... so all new variable assignments are propagations (that depend on earlier decisions)
// - but now the replayed constraints may evaluate to true already and thus not give the forbidden intervals from before anymore...
// so maybe we miss some dependencies this way? a variable was propagated because of a constraint, but after replay the constraint evaluates to true and thus does not add an interval anymore.
// TODO: work out example to explain and test this
}
else
static_assert(always_false<T>::value, "non-exhaustive visitor");
@ -1101,7 +1109,7 @@ namespace polysat {
void solver::backjump(unsigned new_level) {
SASSERT(new_level >= base_level());
if (m_level != new_level) {
LOG_H3("Backjumping to level " << new_level << " from level " << m_level);
LOG_H3("Backjumping to level " << new_level << " from level " << m_level << " (base_level: " << base_level() << ")");
pop_levels(m_level - new_level);
}
}