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108 lines
3 KiB
C++
108 lines
3 KiB
C++
/*++
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Copyright (c) 2014 Microsoft Corporation
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Module Name:
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opt_pareto.cpp
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Abstract:
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Pareto front utilities
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Author:
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Nikolaj Bjorner (nbjorner) 2014-4-24
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Notes:
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--*/
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#include "opt_pareto.h"
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#include "ast_pp.h"
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#include "model_smt2_pp.h"
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namespace opt {
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// ---------------------
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// GIA pareto algorithm
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lbool gia_pareto::operator()() {
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expr_ref fml(m);
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lbool is_sat = m_solver->check_sat(0, 0);
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if (is_sat == l_true) {
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{
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solver::scoped_push _s(*m_solver.get());
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while (is_sat == l_true) {
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if (m_cancel) {
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return l_undef;
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}
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m_solver->get_model(m_model);
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m_solver->get_labels(m_labels);
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IF_VERBOSE(1,
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model_ref mdl(m_model);
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cb.fix_model(mdl);
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model_smt2_pp(verbose_stream() << "new model:\n", m, *mdl, 0););
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// TBD: we can also use local search to tune solution coordinate-wise.
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mk_dominates();
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is_sat = m_solver->check_sat(0, 0);
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}
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}
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if (is_sat == l_undef) {
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return l_undef;
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}
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SASSERT(is_sat == l_false);
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is_sat = l_true;
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mk_not_dominated_by();
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}
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return is_sat;
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}
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void pareto_base::mk_dominates() {
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unsigned sz = cb.num_objectives();
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expr_ref fml(m);
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expr_ref_vector gt(m), fmls(m);
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for (unsigned i = 0; i < sz; ++i) {
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fmls.push_back(cb.mk_ge(i, m_model));
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gt.push_back(cb.mk_gt(i, m_model));
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}
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fmls.push_back(m.mk_or(gt.size(), gt.c_ptr()));
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fml = m.mk_and(fmls.size(), fmls.c_ptr());
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IF_VERBOSE(10, verbose_stream() << "dominates: " << fml << "\n";);
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TRACE("opt", tout << fml << "\n"; model_smt2_pp(tout, m, *m_model, 0););
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m_solver->assert_expr(fml);
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}
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void pareto_base::mk_not_dominated_by() {
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unsigned sz = cb.num_objectives();
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expr_ref fml(m);
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expr_ref_vector le(m);
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for (unsigned i = 0; i < sz; ++i) {
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le.push_back(cb.mk_le(i, m_model));
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}
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fml = m.mk_not(m.mk_and(le.size(), le.c_ptr()));
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IF_VERBOSE(10, verbose_stream() << "not dominated by: " << fml << "\n";);
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TRACE("opt", tout << fml << "\n";);
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m_solver->assert_expr(fml);
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}
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// ---------------------------------
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// OIA algorithm (without filtering)
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lbool oia_pareto::operator()() {
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solver::scoped_push _s(*m_solver.get());
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lbool is_sat = m_solver->check_sat(0, 0);
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if (m_cancel) {
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is_sat = l_undef;
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}
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if (is_sat == l_true) {
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m_solver->get_model(m_model);
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m_solver->get_labels(m_labels);
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mk_not_dominated_by();
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}
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return is_sat;
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}
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}
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