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address divergence in the case of shared theory symbols. Codeplex issue 147, thanks to George Karpenkov

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2014-12-09 16:04:25 +01:00
commit 08cb8b8de8
74 changed files with 1280 additions and 896 deletions
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3
src/opt/opt_context.cpp
View file

@ -1202,7 +1202,8 @@ namespace opt {
case O_MINIMIZE:
case O_MAXIMIZE: {
inf_eps n = m_optsmt.get_lower(obj.m_index);
if (n.get_infinity().is_zero() &&
if (m_optsmt.objective_is_model_valid(obj.m_index) &&
n.get_infinity().is_zero() &&
n.get_infinitesimal().is_zero() &&
m_model->eval(obj.m_term, val) &&
is_numeral(val, r1)) {

54
src/opt/opt_solver.cpp
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@ -43,6 +43,7 @@ namespace opt {
m(mgr),
m_dump_benchmarks(false),
m_fm(fm),
m_objective_sorts(m),
m_first(true) {
m_params.updt_params(p);
m_params.m_relevancy_lvl = 0;
@ -173,13 +174,56 @@ namespace opt {
}
/**
\brief maximize the value of objective i in the current state.
Return a predicate that blocks the current maximal value.
The result of 'maximize' is post-processed.
When maximization involves shared symbols the model produced
by local optimization does not necessarily satisfy combination
constraints (it may not be a real model).
In this case, the model is post-processed (update_model
causes an additional call to final_check to propagate theory equalities
when 'has_shared' is true).
*/
void opt_solver::maximize_objective(unsigned i, expr_ref& blocker) {
smt::theory_var v = m_objective_vars[i];
m_objective_values[i] = get_optimizer().maximize(v, blocker);
m_context.get_context().update_model();
bool has_shared = false;
inf_eps val = get_optimizer().maximize(v, blocker, has_shared);
inf_eps val2;
m_valid_objectives[i] = true;
if (m_context.get_context().update_model(has_shared)) {
if (has_shared) {
val2 = current_objective_value(i);
if (val2 != val) {
decrement_value(i, val);
}
}
}
else {
SASSERT(has_shared);
// model is not final. We set the current objective to
// close to the optimal (ignoring types).
decrement_value(i, val);
}
m_objective_values[i] = val;
TRACE("opt", { model_ref mdl; tout << m_objective_values[i] << "\n";
get_model(mdl); model_smt2_pp(tout << "update model: ", m, *mdl, 0); });
tout << blocker << "\n";
get_model(mdl); model_smt2_pp(tout << "update model:\n", m, *mdl, 0); });
}
void opt_solver::decrement_value(unsigned i, inf_eps& val) {
if (arith_util(m).is_real(m_objective_sorts[i].get())) {
val -= inf_eps(inf_rational(rational(0),true));
}
else {
val -= inf_eps(inf_rational(rational(1)));
}
m_valid_objectives[i] = false;
}
void opt_solver::get_unsat_core(ptr_vector<expr> & r) {
unsigned sz = m_context.get_unsat_core_size();
@ -232,6 +276,8 @@ namespace opt {
smt::theory_var v = get_optimizer().add_objective(term);
m_objective_vars.push_back(v);
m_objective_values.push_back(inf_eps(rational(-1), inf_rational()));
m_objective_sorts.push_back(m.get_sort(term));
m_valid_objectives.push_back(true);
return v;
}
@ -278,6 +324,8 @@ namespace opt {
void opt_solver::reset_objectives() {
m_objective_vars.reset();
m_objective_values.reset();
m_objective_sorts.reset();
m_valid_objectives.reset();
}
opt_solver& opt_solver::to_opt(solver& s) {

8
src/opt/opt_solver.h
View file

@ -76,6 +76,8 @@ namespace opt {
bool m_objective_enabled;
svector<smt::theory_var> m_objective_vars;
vector<inf_eps> m_objective_values;
sort_ref_vector m_objective_sorts;
svector<bool> m_valid_objectives;
bool m_dump_benchmarks;
static unsigned m_dump_count;
statistics m_stats;
@ -109,6 +111,9 @@ namespace opt {
void maximize_objectives(expr_ref_vector& blockers);
inf_eps const & saved_objective_value(unsigned obj_index);
inf_eps current_objective_value(unsigned obj_index);
bool objective_is_model_valid(unsigned obj_index) const {
return m_valid_objectives[obj_index];
}
vector<inf_eps> const& get_objective_values();
expr_ref mk_ge(unsigned obj_index, inf_eps const& val);
@ -124,6 +129,9 @@ namespace opt {
unsigned num_assumptions, expr * const * assumptions,
char const * name = "benchmarks",
char const * logic = "", char const * status = "unknown", char const * attributes = "");
private:
void decrement_value(unsigned i, inf_eps& val);
};
}

5
src/opt/optsmt.cpp
View file

@ -222,7 +222,6 @@ namespace opt {
for (unsigned i = 0; i < m_lower.size() && !m_cancel; ++i) {
if (m_lower[i] < m_upper[i]) {
mid.push_back((m_upper[i]+m_lower[i])/rational(2));
//mid.push_back(m_upper[i]);
bound = m_s->mk_ge(i, mid[i]);
bounds.push_back(bound);
}
@ -373,6 +372,10 @@ 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];

1
src/opt/optsmt.h
View file

@ -58,6 +58,7 @@ 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);
void update_lower(unsigned idx, inf_eps const& r);