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mirror of https://github.com/Z3Prover/z3 synced 2025-04-08 10:25:18 +00:00
Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2014-01-01 21:13:25 -08:00
parent c5b82796ca
commit af27efbf4a
3 changed files with 82 additions and 3 deletions

View file

@ -171,9 +171,81 @@ namespace opt {
return r;
}
lbool context::execute_pareto() {
// TODO: record a stream of results from pareto front
return execute_lex();
arith_util a(m);
lbool is_sat = execute_box();
if (is_sat != l_true) return is_sat;
// check if solution is bounded
bounds_t bound;
for (unsigned i = 0; i < m_objectives.size(); ++i) {
objective const& obj = m_objectives[i];
if (obj.m_type == O_MAXSMT) {
IF_VERBOSE(0, verbose_stream() << "Pareto optimization is not supported for MAXSMT\n";);
return l_undef;
}
inf_eps lo = get_lower_as_num(i);
inf_eps hi = get_upper_as_num(i);
if (!hi.is_finite()) {
IF_VERBOSE(0, verbose_stream() << "Objective " << i << " has no upper bound\n";);
return l_undef;
}
if (!lo.is_finite()) {
IF_VERBOSE(0, verbose_stream() << "Objective " << i << " has no lower bound\n";);
return l_undef;
}
bound.push_back(std::make_pair(lo, hi));
}
vector<bounds_t> bounds;
bounds.push_back(bound);
display_bounds(verbose_stream(), bound);
opt_solver& s = get_solver();
for (unsigned i = 0; i < bounds.size(); ++i) {
bounds_t b = bounds[i];
vector<inf_eps> mids;
solver::scoped_push _sp(s);
for (unsigned j = 0; j < b.size(); ++j) {
objective const& obj = m_objectives[j];
inf_eps mid = (b[j].second - b[j].first)/rational(2);
mids.push_back(mid);
expr_ref ge = s.mk_ge(obj.m_index, mid);
s.assert_expr(ge);
}
is_sat = s.check_sat_core(0, 0);
switch(is_sat) {
case l_undef:
return is_sat;
case l_true:
for (unsigned j = 0; j < b.size(); ++j) {
b[j] = std::make_pair(b[j].first, mids[j]);
}
display_bounds(verbose_stream(), b);
bounds.push_back(b);
break;
case l_false: {
bounds_t b2(b);
for (unsigned j = 0; j < b.size(); ++j) {
b2[j].second = mids[j];
if (j > 0) {
b2[j-1].second = b[j-1].second;
}
display_bounds(verbose_stream(), b2);
bounds.push_back(b2);
}
break;
}
}
}
return is_sat;
}
void context::display_bounds(std::ostream& out, bounds_t const& b) const {
for (unsigned i = 0; i < m_objectives.size(); ++i) {
objective const& obj = m_objectives[i];
display_objective(out, obj);
out << " |-> [" << b[i].first << ":" << b[i].second << "]\n";
}
}
opt_solver& context::get_solver() {

View file

@ -39,6 +39,7 @@ namespace opt {
struct free_func_visitor;
typedef map<symbol, maxsmt*, symbol_hash_proc, symbol_eq_proc> map_t;
typedef map<symbol, unsigned, symbol_hash_proc, symbol_eq_proc> map_id;
typedef vector<std::pair<inf_eps, inf_eps> > bounds_t;
enum objective_t {
O_MAXIMIZE,
O_MINIMIZE,
@ -148,6 +149,8 @@ namespace opt {
opt_solver& get_solver();
void display_objective(std::ostream& out, objective const& obj) const;
void display_bounds(std::ostream& out, bounds_t const& b) const;
void validate_lex();

View file

@ -1437,7 +1437,11 @@ namespace smt {
if (val != l_undef &&
ctx.get_assign_level(thl) == ctx.get_base_level()) {
if (val == l_true) {
k -= n.get_unsigned();
unsigned m = n.get_unsigned();
if (k < m) {
return;
}
k -= m;
}
continue;
}