mirrors/z3
3
0
Fork 0
mirror of https://github.com/Z3Prover/z3 synced 2025-07-31 08:23:17 +00:00
Code Activity

Fix missing boolean propagation after boolean conflict

Browse source 
Usually in SAT solving, the conflict clause has at least two false literals at the max level (otherwise, the last literal would have been propagated at an earlier level).
But here we are adding clauses on demand; so after backtracking we may have the case that the conflict clause has exactly one undefined literal that must be propagated explicitly.
This commit is contained in:
Jakob Rath 2023-02-01 14:21:02 +01:00
parent 783bd60598
commit 0d56edb65c
7 changed files with 66 additions and 20 deletions
Download patch file Download diff file Expand all files Collapse all files

14
src/math/polysat/conflict.cpp
View file

@ -216,7 +216,7 @@ namespace polysat {
logger().begin_conflict();
}
void conflict::init(clause const& cl) {
void conflict::init(clause& cl) {
LOG("Conflict: clause " << cl);
SASSERT(empty());
m_level = s.m_level;
@ -225,6 +225,14 @@ namespace polysat {
SASSERT_EQ(c.bvalue(s), l_false);
insert(~c);
}
// NOTE: usually in SAT solving, the conflict clause has at least two false literals at the max level.
// (otherwise, the last literal would have been propagated at an earlier level.)
// This is not true if we add clauses on demand;
// after backtracking we may have the case that the conflict clause has
// exactly one undefined literal that must be propagated explicitly.
m_lemmas.push_back(&cl);
SASSERT(!empty());
logger().begin_conflict();
}
@ -330,6 +338,10 @@ namespace polysat {
// TODO: pass to inference_logger (with name)
}
void conflict::restore_lemma(clause_ref lemma) {
m_lemmas.push_back(std::move(lemma));
}
void conflict::remove(signed_constraint c) {
SASSERT(contains(c));
m_literals.remove(c.blit().index());