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fixes to mod/div elimination

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elimination of mod/div should be applied to all occurrences of x under mod/div at the same time. It affects performance and termination to perform elimination on each occurrence since substituting in two new variables for eliminated x doubles the number of variables under other occurrences.

Also generalize inequality resolution to use div.

The new features are still disabled.
This commit is contained in:
Nikolaj Bjorner 2022-08-14 11:34:03 -07:00
parent f014e30d46
commit 1d87592b13
3 changed files with 299 additions and 274 deletions
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50
src/qe/qsat.cpp
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@ -241,9 +241,8 @@ namespace qe {
while (sz0 != todo.size()) {
app* a = to_app(todo.back());
todo.pop_back();
if (mark.is_marked(a)) {
if (mark.is_marked(a))
continue;
}
mark.mark(a);
if (m_lit2pred.find(a, p)) {
@ -284,9 +283,8 @@ namespace qe {
m_elevel.insert(r, l);
eq = m.mk_eq(r, a);
defs.push_back(eq);
if (!is_predicate(a, l.max())) {
if (!is_predicate(a, l.max()))
insert(r, l);
}
level.merge(l);
}
}
@ -637,57 +635,55 @@ namespace qe {
check_cancel();
expr_ref_vector asms(m_asms);
m_pred_abs.get_assumptions(m_model.get(), asms);
if (m_model.get()) {
if (m_model.get())
validate_assumptions(*m_model.get(), asms);
}
TRACE("qe", tout << asms << "\n";);
solver& s = get_kernel(m_level).s();
lbool res = s.check_sat(asms);
switch (res) {
case l_true:
s.get_model(m_model);
CTRACE("qe", !m_model, tout << "no model\n");
if (!m_model)
return l_undef;
SASSERT(validate_defs("check_sat"));
SASSERT(!m_model.get() || validate_assumptions(*m_model.get(), asms));
SASSERT(validate_model(asms));
TRACE("qe", s.display(tout); display(tout << "\n", *m_model.get()); display(tout, asms); );
if (m_level == 0) {
if (m_level == 0)
m_model_save = m_model;
}
push();
if (m_level == 1 && m_mode == qsat_maximize) {
if (m_level == 1 && m_mode == qsat_maximize)
maximize_model();
}
break;
case l_false:
switch (m_level) {
case 0:
return l_false;
case 1:
if (m_mode == qsat_sat) {
if (m_mode == qsat_sat)
return l_true;
}
if (m_model.get()) {
SASSERT(validate_assumptions(*m_model.get(), asms));
if (!project_qe(asms)) return l_undef;
if (!project_qe(asms))
return l_undef;
}
else {
else
pop(1);
}
break;
default:
if (m_model.get()) {
if (!project(asms)) return l_undef;
if (!project(asms))
return l_undef;
}
else {
else
pop(1);
}
break;
}
break;
case l_undef:
TRACE("qe", tout << "check-sat is undef\n");
return res;
}
}
@ -833,11 +829,10 @@ namespace qe {
}
}
bool get_core(expr_ref_vector& core, unsigned level) {
void get_core(expr_ref_vector& core, unsigned level) {
SASSERT(validate_defs("get_core"));
get_kernel(level).get_core(core);
m_pred_abs.pred2lit(core);
return true;
}
bool minimize_core(expr_ref_vector& core, unsigned level) {
@ -905,9 +900,7 @@ namespace qe {
SASSERT(m_level == 1);
expr_ref fml(m);
model& mdl = *m_model.get();
if (!get_core(core, m_level)) {
return false;
}
get_core(core, m_level);
SASSERT(validate_core(mdl, core));
get_vars(m_level);
SASSERT(validate_assumptions(mdl, core));
@ -927,7 +920,7 @@ namespace qe {
}
bool project(expr_ref_vector& core) {
if (!get_core(core, m_level)) return false;
get_core(core, m_level);
TRACE("qe", display(tout); display(tout << "core\n", core););
SASSERT(m_level >= 2);
expr_ref fml(m);
@ -950,14 +943,17 @@ namespace qe {
if (level.max() == UINT_MAX) {
num_scopes = 2*(m_level/2);
}
else if (level.max() + 2 > m_level) {
// fishy - this can happen.
TRACE("qe", tout << "max-level: " << level.max() << " level: " << m_level << "\n");
return false;
}
else {
if (level.max() + 2 > m_level) return false;
SASSERT(level.max() + 2 <= m_level);
num_scopes = m_level - level.max();
SASSERT(num_scopes >= 2);
if ((num_scopes % 2) != 0) {
if ((num_scopes % 2) != 0)
--num_scopes;
}
}
pop(num_scopes);