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experiment with sat solver

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2014-05-14 19:40:58 -07:00
parent 81c2560854
commit d849b5c637
5 changed files with 149 additions and 53 deletions
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64
src/opt/opt_sls_solver.h
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@ -125,6 +125,38 @@ namespace opt {
}
}
static expr_ref soft2bv(expr_ref_vector const& soft, vector<rational> const& weights) {
ast_manager& m = soft.get_manager();
pb::card_pb_rewriter pb2bv(m);
rational upper(1);
expr_ref objective(m);
for (unsigned i = 0; i < weights.size(); ++i) {
upper += 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 < soft.size(); ++i) {
pb2bv(soft[i], tmp);
es.push_back(m.mk_ite(tmp, bv.mk_numeral(den*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;
}
protected:
typedef bvsls_opt_engine::optimization_result opt_result;
@ -143,37 +175,9 @@ namespace opt {
m_solver->pop(n);
}
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);
@ -224,7 +228,7 @@ namespace opt {
m_bvsls = alloc(bvsls_opt_engine, m, m_params);
}
assertions2sls();
expr_ref objective = soft2bv();
expr_ref objective = soft2bv(m_soft, m_weights);
opt_result res(m);
res.is_sat = l_undef;
try {