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updated conflict state

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2022-02-01 11:47:33 -08:00
parent 486cc632d0
commit c48f14e537
8 changed files with 1085 additions and 1067 deletions
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74
src/math/polysat/conflict.cpp
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@ -51,6 +51,10 @@ namespace polysat {
out << " vars";
for (auto v : m_vars)
out << " v" << v;
if (!m_bail_vars.empty())
out << " bail vars";
for (auto v : m_bail_vars)
out << " v" << v;
return out;
}
@ -60,6 +64,7 @@ namespace polysat {
m_constraints.reset();
m_literals.reset();
m_vars.reset();
m_bail_vars.reset();
m_conflict_var = null_var;
m_bailout = false;
SASSERT(empty());
@ -139,14 +144,26 @@ namespace polysat {
m_constraints.push_back(c);
}
void conflict::propagate(signed_constraint c) {
cm().ensure_bvar(c.get());
switch (c.bvalue(s)) {
case l_undef:
s.assign_eval(c.blit());
break;
case l_true:
break;
case l_false:
break;
}
insert(c);
}
void conflict::insert_vars(signed_constraint c) {
for (pvar v : c->vars())
if (s.is_assigned(v))
m_vars.insert(v);
}
/**
* Premises can either be justified by a Clause or by a value assignment.
* Premises that are justified by value assignments are not assigned (the bvalue is l_undef)
@ -232,10 +249,18 @@ namespace polysat {
SASSERT(contains_literal(lit));
SASSERT(!contains_literal(~lit));
remove_literal(lit);
signed_constraint c = s.lit2cnstr(lit);
unset_mark(c);
insert_vars(c);
bool has_decision = false;
for (pvar v : c->vars())
if (s.is_assigned(v) && s.m_justification[v].is_decision())
m_bail_vars.insert(v), has_decision = true;
if (!has_decision) {
remove(c);
for (pvar v : c->vars())
if (s.is_assigned(v))
m_vars.insert(v);
}
}
/**
@ -313,42 +338,24 @@ namespace polysat {
bool conflict::resolve_value(pvar v) {
// NOTE:
// In the "standard" case where "v = val" is on the stack:
// - core contains both false and true constraints
// (originally only false ones, but additional true ones may come from saturation)
// forbidden interval projection is performed at top level
SASSERT(v != conflict_var());
if (is_bailout()) {
if (!s.m_justification[v].is_decision())
m_vars.remove(v);
return false;
}
SASSERT(v != conflict_var());
auto const& j = s.m_justification[v];
s.inc_activity(v);
#if 0
if (j.is_decision() && m_vars.contains(v)) {
set_bailout();
if (j.is_decision() && m_bail_vars.contains(v))
return false;
}
#endif
s.inc_activity(v);
m_vars.remove(v);
if (j.is_propagation()) {
for (auto const& c : s.m_viable.get_constraints(v)) {
if (!c->has_bvar()) {
// it is a side-condition that was not propagated already.
// it is true in the current variable assignment.
cm().ensure_bvar(c.get());
s.assign_eval(c.blit());
}
insert(c);
}
}
if (is_bailout())
goto bailout;
if (j.is_propagation())
for (auto const& c : s.m_viable.get_constraints(v))
propagate(c);
LOG("try-explain v" << v);
if (try_explain(v))
@ -365,6 +372,7 @@ namespace polysat {
}
LOG("bailout v" << v);
set_bailout();
bailout:
if (s.is_assigned(v) && j.is_decision())
m_vars.insert(v);
return false;