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#fix #5328

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in-processing for "pure" PB constraints isn't model preserving and therefore removed.
This commit is contained in:
Nikolaj Bjorner 2021-06-05 12:02:33 -07:00
parent 85b672ee85
commit 1fd6b66ecc
2 changed files with 13 additions and 39 deletions
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39
src/sat/smt/pb_solver.cpp
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@ -132,7 +132,6 @@ namespace pb {
remove_constraint(p, "is tight");
}
else {
unsigned sz = p.size();
clear_watch(p);
unsigned j = 0;
@ -1470,7 +1469,6 @@ namespace pb {
return true;
}
else if (c.lit() != sat::null_literal && value(c.lit()) != l_true) {
// else if (c.lit() != sat::null_literal && value(c.lit()) == l_false) {
return true;
}
else {
@ -2025,7 +2023,7 @@ namespace pb {
unit_strengthen();
cleanup_clauses();
cleanup_constraints();
update_pure();
count++;
}
while (count < 10 && (m_simplify_change || trail_sz < s().init_trail_size()));
@ -2047,41 +2045,6 @@ namespace pb {
// if (s().m_clauses.size() < 80000) lp_lookahead_reduction();
}
/*
* ~lit does not occur in clauses
* ~lit is only in one constraint use list
* lit == C
* -> ignore assignments to ~lit for C
*
* ~lit does not occur in clauses
* lit is only in one constraint use list
* lit == C
* -> negate: ~lit == ~C
*/
void solver::update_pure() {
//return;
for (constraint* cp : m_constraints) {
literal lit = cp->lit();
if (lit != sat::null_literal &&
!cp->is_pure() &&
value(lit) == l_undef &&
get_wlist(~lit).size() == 1 &&
m_clause_use_list.get(lit).empty()) {
clear_watch(*cp);
cp->negate();
lit.neg();
}
if (lit != sat::null_literal &&
!cp->is_pure() &&
m_cnstr_use_list[(~lit).index()].size() == 1 &&
get_wlist(lit).size() == 1 &&
m_clause_use_list.get(~lit).empty()) {
cp->set_pure();
get_wlist(~lit).erase(sat::watched(cp->cindex())); // just ignore assignments to false
}
}
}
void solver::mutex_reduction() {
literal_vector lits;
for (unsigned v = 0; v < s().num_vars(); ++v) {