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fix #5254

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This commit is contained in:
Nikolaj Bjorner 2021-05-17 15:41:51 -07:00
parent 1a432529dd
commit 8384f38eb5
5 changed files with 49 additions and 61 deletions
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17
src/opt/opt_context.cpp
View file

@ -1714,23 +1714,8 @@ namespace opt {
objective const& obj = m_objectives[i];
switch(obj.m_type) {
case O_MINIMIZE:
case O_MAXIMIZE: {
inf_eps n = m_optsmt.get_lower(obj.m_index);
if (false && // theory_lra doesn't produce infinitesimals
m_optsmt.objective_is_model_valid(obj.m_index) &&
n.get_infinity().is_zero() &&
n.get_infinitesimal().is_zero() &&
is_numeral((*m_model)(obj.m_term), r1)) {
rational r2 = n.get_rational();
if (obj.m_type == O_MINIMIZE) {
r1.neg();
}
CTRACE("opt", r1 != r2, tout << obj.m_term << " evaluates to " << r1 << " but has objective " << r2 << "\n";);
CTRACE("opt", r1 != r2, tout << *m_model;);
SASSERT(r1 == r2);
}
case O_MAXIMIZE:
break;
}
case O_MAXSMT: {
rational value(0);
for (unsigned i = 0; i < obj.m_terms.size(); ++i) {

67
src/opt/opt_solver.cpp
View file

@ -244,23 +244,46 @@ namespace opt {
smt::theory_var v = m_objective_vars[i];
bool has_shared = false;
m_last_model = nullptr;
//
// compute an optimization hint.
// The hint is valid if there are no shared symbols (a pure LP).
// Generally, the hint is not necessarily valid and has to be checked
// relative to other theories.
//
inf_eps val = get_optimizer().maximize(v, blocker, has_shared);
m_context.get_model(m_last_model);
inf_eps val2;
m_valid_objectives[i] = true;
has_shared = true;
TRACE("opt", tout << (has_shared?"has shared":"non-shared") << " " << val << " " << blocker << "\n";
if (m_last_model) tout << *m_last_model << "\n";);
if (!m_models[i])
m_models.set(i, m_last_model.get());
//
// retrieve value of objective from current model and update
// current optimal.
//
auto update_objective = [&]() {
rational r;
expr_ref value = (*m_last_model)(m_objective_terms.get(i));
if (arith_util(m).is_numeral(value, r) && r > m_objective_values[i])
m_objective_values[i] = inf_eps(r);
};
update_objective();
auto decrement = [&]() {
//
// check that "val" obtained from optimization hint is a valid bound.
//
auto check_bound = [&]() {
SASSERT(has_shared);
decrement_value(i, val);
bool ok = bound_value(i, val);
if (l_true != m_context.check(0, nullptr))
return false;
m_context.get_model(m_last_model);
return true;
m_context.get_model(m_last_model);
update_objective();
return ok;
};
if (!val.is_finite()) {
@ -270,19 +293,16 @@ namespace opt {
TRACE("opt", tout << "updated\n";);
m_last_model = nullptr;
m_context.get_model(m_last_model);
if (has_shared && val != current_objective_value(i)) {
if (!decrement())
return false;
}
else {
if (!has_shared || val == current_objective_value(i))
m_models.set(i, m_last_model.get());
}
else if (!check_bound())
return false;
}
else if (!decrement())
else if (!check_bound())
return false;
m_objective_values[i] = val;
TRACE("opt", {
tout << "objective: " << mk_pp(m_objective_terms[i].get(), m) << "\n";
tout << "objective: " << mk_pp(m_objective_terms.get(i), m) << "\n";
tout << "maximal value: " << val << "\n";
tout << "new condition: " << blocker << "\n";
if (m_models[i]) model_smt2_pp(tout << "update model:\n", m, *m_models[i], 0);
@ -291,10 +311,9 @@ namespace opt {
return true;
}
lbool opt_solver::decrement_value(unsigned i, inf_eps& val) {
bool opt_solver::bound_value(unsigned i, inf_eps& val) {
push_core();
expr_ref ge = mk_ge(i, val);
TRACE("opt", tout << ge << "\n";);
assert_expr(ge);
lbool is_sat = m_context.check(0, nullptr);
is_sat = adjust_result(is_sat);
@ -303,19 +322,7 @@ namespace opt {
m_models.set(i, m_last_model.get());
}
pop_core(1);
TRACE("opt", tout << is_sat << "\n";);
if (is_sat != l_true) {
// cop-out approximation
if (arith_util(m).is_real(m_objective_terms.get(i))) {
val -= inf_eps(inf_rational(rational(0), true));
}
else {
val -= inf_eps(inf_rational(rational(1)));
}
m_valid_objectives[i] = false;
}
return is_sat;
return is_sat == l_true;
}
lbool opt_solver::adjust_result(lbool r) {
@ -338,10 +345,12 @@ namespace opt {
for (unsigned i = m_models.size(); i-- > 0; ) {
auto* mdl = m_models[i];
if (mdl) {
TRACE("opt", tout << "get " << i << "\n" << *mdl << "\n";);
m = mdl;
return;
}
}
TRACE("opt", tout << "get last\n";);
m = m_last_model.get();
}
@ -384,7 +393,6 @@ namespace opt {
m_objective_vars.push_back(v);
m_objective_values.push_back(inf_eps(rational::minus_one(), inf_rational()));
m_objective_terms.push_back(term);
m_valid_objectives.push_back(true);
m_models.push_back(nullptr);
return v;
}
@ -486,7 +494,6 @@ namespace opt {
m_objective_vars.reset();
m_objective_values.reset();
m_objective_terms.reset();
m_valid_objectives.reset();
}
opt_solver& opt_solver::to_opt(solver& s) {

6
src/opt/opt_solver.h
View file

@ -77,7 +77,6 @@ namespace opt {
vector<inf_eps> m_objective_values;
sref_vector<model> m_models;
expr_ref_vector m_objective_terms;
bool_vector m_valid_objectives;
bool m_dump_benchmarks;
static unsigned m_dump_count;
statistics m_stats;
@ -124,9 +123,6 @@ namespace opt {
inf_eps const & saved_objective_value(unsigned obj_index);
inf_eps current_objective_value(unsigned obj_index);
model* get_model_idx(unsigned obj_index) { return m_models[obj_index]; }
bool objective_is_model_valid(unsigned obj_index) const {
return m_valid_objectives[obj_index];
}
bool was_unknown() const { return m_was_unknown; }
@ -147,7 +143,7 @@ namespace opt {
symbol const& logic = symbol::null, char const * status = "unknown", char const * attributes = "");
private:
lbool decrement_value(unsigned i, inf_eps& val);
bool bound_value(unsigned i, inf_eps& val);
void set_model(unsigned i);
lbool adjust_result(lbool r);
};

19
src/opt/optsmt.cpp
View file

@ -195,24 +195,25 @@ namespace opt {
lbool optsmt::geometric_lex(unsigned obj_index, bool is_maximize) {
TRACE("opt", tout << "index: " << obj_index << " is-max: " << is_maximize << "\n";);
arith_util arith(m);
bool is_int = arith.is_int(m_objs[obj_index].get());
bool is_int = arith.is_int(m_objs.get(obj_index));
lbool is_sat = l_true;
expr_ref bound(m), last_bound(m);
for (unsigned i = 0; i < obj_index; ++i) {
for (unsigned i = 0; i < obj_index; ++i)
commit_assignment(i);
}
unsigned steps = 0;
unsigned step_incs = 0;
rational delta_per_step(1);
unsigned num_scopes = 0;
inf_eps last_objective = inf_eps(rational(-1), inf_rational(0));
while (m.inc()) {
SASSERT(delta_per_step.is_int());
SASSERT(delta_per_step.is_pos());
is_sat = m_s->check_sat(0, nullptr);
TRACE("opt", tout << "check " << is_sat << "\n";
tout << "last bound: " << last_bound << "\n";
tout << "lower: " << m_lower[obj_index] << "\n";
tout << "upper: " << m_upper[obj_index] << "\n";
);
@ -221,6 +222,7 @@ namespace opt {
m_s->get_model(m_model);
SASSERT(m_model);
inf_eps obj = m_s->saved_objective_value(obj_index);
TRACE("opt", tout << "saved objective: " << obj << "\n";);
update_lower_lex(obj_index, obj, is_maximize);
if (!is_int || !m_lower[obj_index].is_finite()) {
delta_per_step = rational(1);
@ -233,12 +235,12 @@ namespace opt {
else {
++steps;
}
if (delta_per_step > rational::one()) {
if (delta_per_step > rational::one() || obj == last_objective) {
m_s->push();
++num_scopes;
bound = m_s->mk_ge(obj_index, obj + inf_eps(delta_per_step));
}
TRACE("opt", tout << "delta: " << delta_per_step << " " << bound << "\n";);
last_objective = obj;
if (bound == last_bound) {
break;
}
@ -357,6 +359,7 @@ namespace opt {
}
void optsmt::update_lower_lex(unsigned idx, inf_eps const& v, bool is_maximize) {
TRACE("opt", tout << v << " lower: " << m_lower[idx] << "\n";);
if (v > m_lower[idx]) {
m_lower[idx] = v;
IF_VERBOSE(1,
@ -368,6 +371,7 @@ namespace opt {
for (unsigned i = idx+1; i < m_vars.size(); ++i) {
m_lower[i] = m_s->saved_objective_value(i);
}
TRACE("opt", tout << "update best model " << *m_model << "\n";);
m_best_model = m_model;
m_s->get_labels(m_labels);
m_context.set_model(m_model);
@ -532,10 +536,6 @@ namespace opt {
return m_lower[i];
}
bool optsmt::objective_is_model_valid(unsigned index) const {
return m_s->objective_is_model_valid(index);
}
inf_eps optsmt::get_upper(unsigned i) const {
if (i >= m_upper.size()) return inf_eps();
return m_upper[i];
@ -543,6 +543,7 @@ namespace opt {
void optsmt::get_model(model_ref& mdl, svector<symbol> & labels) {
mdl = m_best_model.get();
TRACE("opt", tout << *mdl << "\n";);
labels = m_labels;
}

1
src/opt/optsmt.h
View file

@ -61,7 +61,6 @@ namespace opt {
void commit_assignment(unsigned index);
inf_eps get_lower(unsigned index) const;
inf_eps get_upper(unsigned index) const;
bool objective_is_model_valid(unsigned index) const;
void get_model(model_ref& mdl, svector<symbol>& labels);
model* get_model(unsigned index) const { return m_models[index]; }