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move sls functionality to solver

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2014-04-19 20:50:44 -07:00
parent 3f5ed8ff11
commit 1f66e46c67
2 changed files with 51 additions and 122 deletions
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57
src/opt/opt_sls_solver.h
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@ -23,6 +23,8 @@ Notes:
#include "solver_na2as.h"
#include "card2bv_tactic.h"
#include "pb_sls.h"
#include "bvsls_opt_engine.h"
namespace opt {
@ -32,19 +34,24 @@ namespace opt {
scoped_ptr<bvsls_opt_engine> m_bvsls;
scoped_ptr<smt::pb_sls> m_pbsls;
pb::card_pb_rewriter m_pb2bv;
vector<rational> m_weights;
expr_ref_vector m_soft;
model_ref m_model;
expr_ref m_objective;
params_ref m_params;
symbol m_engine;
public:
sls_solver(ast_manager & m, solver* s, expr* to_maximize, params_ref const& p):
sls_solver(ast_manager & m, solver* s,
expr_ref_vector const& soft,
vector<rational> const& weights,
params_ref const& p):
solver_na2as(m),
m(m),
m_solver(s),
m_bvsls(0),
m_pbsls(0),
m_pb2bv(m),
m_objective(to_maximize, m)
m_weights(weights),
m_soft(soft)
{
}
virtual ~sls_solver() {}
@ -116,7 +123,7 @@ namespace opt {
if (r == l_true) {
m_solver->get_model(m_model);
if (m_engine == symbol("pb")) {
pbsls_opt();
}
else {
bvsls_opt();
@ -132,6 +139,37 @@ namespace opt {
}
private:
// convert soft constraints to bit-vector objective.
expr_ref soft2bv() {
rational upper(1);
expr_ref objective(m);
for (unsigned i = 0; i < m_weights.size(); ++i) {
upper += m_weights[i];
}
expr_ref zero(m), tmp(m);
bv_util bv(m);
expr_ref_vector es(m);
rational num = numerator(upper);
rational den = denominator(upper);
rational maxval = num*den;
unsigned bv_size = maxval.get_num_bits();
zero = bv.mk_numeral(rational(0), bv_size);
for (unsigned i = 0; i < m_soft.size(); ++i) {
m_pb2bv(m_soft[i].get(), tmp);
es.push_back(m.mk_ite(tmp, bv.mk_numeral(den*m_weights[i], bv_size), zero));
}
if (es.empty()) {
objective = bv.mk_numeral(0, bv_size);
}
else {
objective = es[0].get();
for (unsigned i = 1; i < es.size(); ++i) {
objective = bv.mk_bv_add(objective, es[i].get());
}
}
return objective;
}
void assertions2sls() {
expr_ref tmp(m);
goal_ref g(alloc(goal, m, true, false));
@ -162,13 +200,9 @@ namespace opt {
for (unsigned i = 0; i < m_solver->get_num_assertions(); ++i) {
m_pbsls->add(m_solver->get_assertion(i));
}
#if 0
TBD:
for (unsigned i = 0; i < m_num_soft; ++i) {
m_pbsls->add(m_soft[i].get(), m_weights[i].get());
for (unsigned i = 0; i < m_soft.size(); ++i) {
m_pbsls->add(m_soft[i].get(), m_weights[i]);
}
#endif
lbool is_sat = (*m_pbsls.get())();
if (is_sat == l_true) {
m_bvsls->get_model(m_model);
@ -181,7 +215,8 @@ namespace opt {
m_bvsls = alloc(bvsls_opt_engine, m, m_params);
}
assertions2sls();
opt_result or = m_bvsls->optimize(m_objective, m_model, true);
expr_ref objective = soft2bv();
opt_result or = m_bvsls->optimize(objective, m_model, true);
SASSERT(or.is_sat == l_true || or.is_sat == l_undef);
if (or.is_sat == l_true) {
m_bvsls->get_model(m_model);