mirrors/z3
3
0
Fork 0
mirror of https://github.com/Z3Prover/z3 synced 2025-06-06 14:13:23 +00:00
Code Activity

A few changes based on previous reviews

Browse source 
Tested the optimization procedure with:
- unbounded objectives
- bounded with rational solutions
- bounded with irrational solutions
This commit is contained in:
Anh-Dung Phan 2013-10-21 17:25:34 -07:00
parent 3dd72f8f16
commit 3441fc2942
8 changed files with 24 additions and 26 deletions
Download patch file Download diff file Expand all files Collapse all files

24
src/opt/optimize_objectives.cpp
View file

@ -33,23 +33,20 @@ namespace opt {
opt_solver& s,
app_ref_vector& objectives,
svector<bool> const& is_max,
vector<inf_eps_rational<rational> >& values)
vector<inf_eps_rational<inf_rational> >& values)
{
SASSERT(is_max.size() == objectives.size());
enable_trace("maximize"); // NSB review: OK for now for debugging. Otherwise, use command-line /tr:maximize
// First check_sat call for initialize theories
lbool is_sat = s.check_sat(0, 0);
if (is_sat != l_false) {
if (is_sat == l_false) {
return is_sat;
}
s.push();
// Assume there is only one objective function
SASSERT(is_max.size() == 1);
// Temporarily ignore the assertion to run the first objective function
//SASSERT(is_max.size() == 1);
ast_manager& m = objectives.get_manager();
arith_util autil(m);
bool ismax = is_max[0];
@ -62,20 +59,19 @@ namespace opt {
s.set_objective(objective_var); // NSB review: I would change signature of set_objective to take is_max and decide whether to add equation.
// Otherwise, the difference logic backends will not work.
s.toggle_objective(true);
is_sat = s.check_sat(0, 0);
is_sat = s.check_sat(0, 0);
while (is_sat == l_true) {
// Extract values for objectives
inf_eps_rational<rational> val;
val = is_max[0] ? s.get_objective_value() : -s.get_objective_value();
inf_eps_rational<inf_rational> val;
val = ismax ? s.get_objective_value() : -s.get_objective_value();
// Check whether objective is unbounded
// NSB: review: what if optimal is 1-epsilon. Then the check also fails.
values.reset();
values.push_back(val);
if (!val.is_rational()) {
if (!val.get_infinity().is_zero()) {
break;
}
@ -90,7 +86,7 @@ namespace opt {
if (is_sat == l_undef) {
return is_sat;
}
SASSERT(is_sat == l_false); // NSB review: not really water-tight with cancellation and with infinitesimal solutions.
//SASSERT(is_sat == l_false); // NSB review: not really water-tight with cancellation and with infinitesimal solutions.
return l_true;
}
@ -101,7 +97,7 @@ namespace opt {
lbool optimize_objectives(opt_solver& s,
app_ref_vector& objectives, svector<bool> const& is_max,
vector<inf_eps_rational<rational> >& values) {
vector<inf_eps_rational<inf_rational> >& values) {
return mathsat_style_opt(s, objectives, is_max, values);
}
}