mirrors/z3
3
0
Fork 0
mirror of https://github.com/Z3Prover/z3 synced 2025-05-17 04:34:45 +00:00
Code Activity

compute polysat unsat core

Browse source
This commit is contained in:
Jakob Rath 2023-02-03 17:37:09 +01:00
parent 579275a17d
commit 1a733a3a50
3 changed files with 105 additions and 13 deletions
Download patch file Download diff file Expand all files Collapse all files

84
src/math/polysat/conflict.cpp
View file

@ -412,7 +412,7 @@ namespace polysat {
s.inc_activity(v);
m_vars.remove(v);
for (auto const& c : s.m_viable.get_constraints(v))
for (signed_constraint const c : s.m_viable.get_constraints(v))
insert(c);
for (auto const& i : s.m_viable.units(v)) {
insert(s.eq(i.lo(), i.lo_val()));
@ -500,18 +500,82 @@ namespace polysat {
#endif
void conflict::find_deps(dependency_vector& out_deps) const {
sat::literal_vector todo;
sat::literal_set done;
sat::literal_vector todo_lits;
sat::literal_set done_lits;
unsigned_vector todo_vars;
uint_set done_vars;
indexed_uint_set deps;
LOG("conflict: " << *this);
LOG("Conflict: " << *this);
// TODO: starting at literals/variables in the conflict, chase propagations backwards and accumulate dependencies.
verbose_stream() << "WARNING: unsat_core requested but dependency tracking in polysat is TODO\n";
for (signed_constraint c : *this) {
dependency d = s.m_bvars.dep(c.blit());
if (!d.is_null())
deps.insert(d.val());
auto const enqueue_lit = [&](sat::literal lit) {
if (done_lits.contains(lit))
return;
// verbose_stream() << "enqueue " << lit_pp(s, lit) << "\n";
todo_lits.push_back(lit);
done_lits.insert(lit);
};
auto const enqueue_var = [&](pvar v) {
if (done_vars.contains(v))
return;
// verbose_stream() << "enqueue v" << v << "\n";
todo_vars.push_back(v);
done_vars.insert(v);
};
// Starting at literals/variables in the conflict, chase propagations backwards and accumulate dependencies.
for (signed_constraint c : *this)
enqueue_lit(c.blit());
for (pvar v : m_vars)
enqueue_var(v);
while (!todo_vars.empty() || !todo_lits.empty()) {
while (!todo_vars.empty()) {
pvar const v = todo_vars.back();
todo_vars.pop_back();
if (s.m_justification[v].is_decision())
continue;
SASSERT(s.m_justification[v].is_propagation());
for (signed_constraint c : s.m_viable.get_constraints(v))
enqueue_lit(c.blit());
for (auto const& i : s.m_viable.units(v)) {
enqueue_lit(s.try_eval(s.eq(i.lo(), i.lo_val())));
enqueue_lit(s.try_eval(s.eq(i.hi(), i.hi_val())));
}
}
while (!todo_lits.empty()) {
sat::literal const lit = todo_lits.back();
todo_lits.pop_back();
dependency const d = s.m_bvars.dep(lit);
if (!d.is_null())
deps.insert(d.val());
if (s.m_bvars.is_decision(lit))
continue;
else if (s.m_bvars.is_assumption(lit))
continue;
else if (s.m_bvars.is_bool_propagation(lit)) {
for (sat::literal other : *s.m_bvars.reason(lit))
enqueue_lit(other);
}
else if (s.m_bvars.is_evaluation(lit)) {
unsigned const lvl = s.m_bvars.level(lit);
for (pvar v : s.lit2cnstr(lit).vars()) {
if (!s.is_assigned(v))
continue;
if (s.get_level(v) > lvl)
continue;
enqueue_var(v);
}
}
else {
UNREACHABLE();
}
}
}
for (unsigned d : deps)

30
src/math/polysat/solver.cpp
View file

@ -153,7 +153,7 @@ namespace polysat {
if (is_conflict())
return; // no need to do anything if we already have a conflict at base level
sat::literal lit = c.blit();
LOG("New constraint: " << c);
LOG("New constraint: " << lit_pp(*this, c));
switch (m_bvars.value(lit)) {
case l_false:
// Input literal contradicts current boolean state (e.g., opposite literals in the input)
@ -1085,6 +1085,21 @@ namespace polysat {
assign_eval(lit);
}
sat::literal solver::try_eval(sat::literal lit) {
signed_constraint const c = lit2cnstr(lit);
switch (c.eval(*this)) {
case l_true:
assign_eval(lit);
break;
case l_false:
assign_eval(~lit);
break;
default:
break;
}
return lit;
}
/**
* Activate constraint immediately
* Activation and de-activation of constraints follows the scope controlled by push/pop.
@ -1282,13 +1297,19 @@ namespace polysat {
void solver::report_unsat() {
backjump(base_level());
SASSERT(!m_conflict.empty());
VERIFY(!m_conflict.empty());
}
void solver::unsat_core(dependency_vector& deps) {
VERIFY(is_conflict());
deps.reset();
m_conflict.find_deps(deps);
IF_VERBOSE(10,
verbose_stream() << "polysat unsat_core";
for (auto d : deps)
verbose_stream() << " " << d;
verbose_stream() << "\n";
);
}
std::ostream& solver::display(std::ostream& out) const {
@ -1335,7 +1356,7 @@ namespace polysat {
}
std::ostream& lit_pp::display(std::ostream& out) const {
auto c = s.lit2cnstr(lit);
signed_constraint const c = s.lit2cnstr(lit);
out << lpad(5, lit) << ": " << rpad(30, c);
if (!c)
return out;
@ -1357,6 +1378,9 @@ namespace polysat {
out << " pwatched";
if (c->is_external())
out << " ext";
dependency const d = s.m_bvars.dep(lit);
if (!d.is_null())
out << " dep:" << d.val();
out << " ]";
return out;
}

4
src/math/polysat/solver.h
View file

@ -307,6 +307,10 @@ namespace polysat {
clause_ref mk_clause(std::initializer_list<signed_constraint> cs, bool is_redundant);
clause_ref mk_clause(unsigned n, signed_constraint const* cs, bool is_redundant);
// Evaluate constraint under the current assignment.
sat::literal try_eval(sat::literal lit);
sat::literal try_eval(signed_constraint c) { return try_eval(c.blit()); }
signed_constraint lit2cnstr(sat::literal lit) const { return m_constraints.lookup(lit); }
bool inc() { return m_lim.inc(); }