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https://github.com/Z3Prover/z3
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Instrument fu_malik to use the new SAT solver (WIP)
This commit is contained in:
Anh-Dung Phan
parent
d729e89a7b
commit
4be11f24e1
3 changed files with 73 additions and 19 deletions
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@ -65,7 +65,7 @@ namespace opt {
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for (unsigned i = 0; i < ans.size(); ++i) {
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tout << mk_pp(ans[i].get(), m) << "\n";
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});
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IF_VERBOSE(1, verbose_stream() << "(maxsat.core sat: " << ans.size() << "\n";);
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IF_VERBOSE(0, verbose_stream() << "(maxsat.core sat with lower bound: " << ans.size() << "\n";);
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if (ans.size() > m_answer.size()) {
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m_answer.reset();
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m_answer.append(ans);
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@ -92,7 +92,7 @@ namespace opt {
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core_vars.insert(get_not(core[i]));
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block_vars.remove(core[i]);
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}
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IF_VERBOSE(1, verbose_stream() << "(maxsat.core unsat (core size = " << core.size() << ")\n";);
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IF_VERBOSE(0, verbose_stream() << "(maxsat.core unsat (core size = " << core.size() << ")\n";);
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if (core.empty()) {
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m_upper = m_answer.size();
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return l_true;
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@ -18,6 +18,11 @@ Notes:
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--*/
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#include "fu_malik.h"
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#include "smtlogics/qfbv_tactic.h"
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#include "tactic2solver.h"
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#include "goal.h"
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#include "probe.h"
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#include "smt_context.h"
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/**
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\brief Fu & Malik procedure for MaxSAT. This procedure is based on
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@ -37,25 +42,29 @@ namespace opt {
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struct fu_malik::imp {
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ast_manager& m;
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solver& s;
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ref<solver> m_s;
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expr_ref_vector m_soft;
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expr_ref_vector m_orig_soft;
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expr_ref_vector m_aux;
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expr_ref_vector m_assignment;
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unsigned m_upper_size;
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solver & m_original_solver;
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bool m_use_new_bv_solver;
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imp(ast_manager& m, solver& s, expr_ref_vector const& soft):
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m(m),
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s(s),
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m_s(&s),
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m_soft(soft),
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m_orig_soft(soft),
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m_aux(m),
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m_assignment(m)
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m_assignment(m),
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m_original_solver(s),
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m_use_new_bv_solver(false)
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{
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m_upper_size = m_soft.size() + 1;
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}
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solver& s() { return *m_s; }
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/**
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\brief One step of the Fu&Malik algorithm.
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@ -73,18 +82,30 @@ namespace opt {
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*/
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lbool step() {
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IF_VERBOSE(1, verbose_stream() << "(opt.max_sat step)\n";); // add some count, add some information of # of soft constraints still possibly sat.
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IF_VERBOSE(0, verbose_stream() << "(opt.max_sat step " << m_soft.size() + 2 - m_upper_size << ")\n";);
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expr_ref_vector assumptions(m), block_vars(m);
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for (unsigned i = 0; i < m_soft.size(); ++i) {
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assumptions.push_back(m.mk_not(m_aux[i].get()));
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}
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lbool is_sat = s.check_sat(assumptions.size(), assumptions.c_ptr());
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lbool is_sat = s().check_sat(assumptions.size(), assumptions.c_ptr());
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if (is_sat != l_false) {
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return is_sat;
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}
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ptr_vector<expr> core;
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s.get_unsat_core(core);
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if (m_use_new_bv_solver) {
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unsigned i = 0;
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while (s().check_sat(core.size(), core.c_ptr()) != l_false) {
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IF_VERBOSE(0, verbose_stream() << "(opt.max_sat get-unsat-core round " << i << ")\n";);
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core.push_back(assumptions[i].get());
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++i;
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}
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}
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else {
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s().get_unsat_core(core);
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}
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SASSERT(!core.empty());
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// Update soft-constraints and aux_vars
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for (unsigned i = 0; i < m_soft.size(); ++i) {
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@ -101,9 +122,11 @@ namespace opt {
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m_aux[i] = m.mk_fresh_const("aux", m.mk_bool_sort());
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m_soft[i] = m.mk_or(m_soft[i].get(), block_var);
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block_vars.push_back(block_var);
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s.assert_expr(m.mk_or(m_soft[i].get(), m_aux[i].get()));
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s().assert_expr(m.mk_or(m_soft[i].get(), m_aux[i].get()));
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}
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SASSERT (!block_vars.empty());
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assert_at_most_one(block_vars);
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IF_VERBOSE(0, verbose_stream() << "(opt.max_sat # of non-blocked soft constraints: " << m_soft.size() - block_vars.size() << ")\n";);
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return l_false;
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}
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@ -111,7 +134,7 @@ namespace opt {
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expr_ref has_one(m), has_zero(m), at_most_one(m);
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mk_at_most_one(block_vars.size(), block_vars.c_ptr(), has_one, has_zero);
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at_most_one = m.mk_or(has_one, has_zero);
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s.assert_expr(at_most_one);
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s().assert_expr(at_most_one);
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}
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void mk_at_most_one(unsigned n, expr* const * vars, expr_ref& has_one, expr_ref& has_zero) {
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@ -129,15 +152,40 @@ namespace opt {
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has_zero = m.mk_and(has_zero1, has_zero2);
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}
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}
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void set_solver() {
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solver& current_solver = s();
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goal g(m, true, false);
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unsigned num_assertions = current_solver.get_num_assertions();
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for (unsigned i = 0; i < num_assertions; ++i) {
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g.assert_expr(current_solver.get_assertion(i));
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}
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probe *p = mk_is_qfbv_probe();
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bool all_bv = (*p)(g).is_true();
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if (all_bv) {
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opt_solver & os = opt_solver::to_opt(m_original_solver);
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smt::context & ctx = os.get_context();
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tactic* t = mk_qfbv_tactic(m, ctx.get_params());
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// The new SAT solver hasn't supported unsat core yet
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m_s = mk_tactic2solver(m, t);
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SASSERT(m_s != &m_original_solver);
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for (unsigned i = 0; i < num_assertions; ++i) {
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m_s->assert_expr(current_solver.get_assertion(i));
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}
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m_use_new_bv_solver = true;
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IF_VERBOSE(0, verbose_stream() << "Force to use the new BV solver." << std::endl;);
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}
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}
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// TBD: bug when cancel flag is set, fu_malik returns is_sat == l_true instead of l_undef
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lbool operator()() {
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lbool is_sat = s.check_sat(0,0);
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set_solver();
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lbool is_sat = s().check_sat(0,0);
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if (!m_soft.empty() && is_sat == l_true) {
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solver::scoped_push _sp(s);
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solver::scoped_push _sp(s());
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for (unsigned i = 0; i < m_soft.size(); ++i) {
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m_aux.push_back(m.mk_fresh_const("p", m.mk_bool_sort()));
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s.assert_expr(m.mk_or(m_soft[i].get(), m_aux[i].get()));
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s().assert_expr(m.mk_or(m_soft[i].get(), m_aux[i].get()));
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}
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lbool is_sat = l_true;
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@ -150,7 +198,7 @@ namespace opt {
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if (is_sat == l_true) {
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// Get a list of satisfying m_soft
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model_ref model;
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s.get_model(model);
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s().get_model(model);
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m_assignment.reset();
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for (unsigned i = 0; i < m_orig_soft.size(); ++i) {
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@ -31,6 +31,15 @@ Notes:
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#define MEMLIMIT 300
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tactic * mk_new_sat_tactic(ast_manager & m) {
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IF_VERBOSE(0, verbose_stream() << "Try to use the new SAT solver." << std::endl;);
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tactic * new_sat = cond(mk_or(mk_produce_proofs_probe(), mk_produce_unsat_cores_probe()),
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and_then(mk_simplify_tactic(m),
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mk_smt_tactic()),
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mk_sat_tactic(m));
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return new_sat;
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}
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tactic * mk_qfbv_tactic(ast_manager & m, params_ref const & p) {
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params_ref main_p;
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main_p.set_bool("elim_and", true);
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@ -85,10 +94,7 @@ tactic * mk_qfbv_tactic(ast_manager & m, params_ref const & p) {
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tactic * new_sat = and_then(mk_simplify_tactic(m),
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mk_smt_tactic());
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#else
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tactic * new_sat = cond(mk_or(mk_produce_proofs_probe(), mk_produce_unsat_cores_probe()),
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and_then(mk_simplify_tactic(m),
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mk_smt_tactic()),
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mk_sat_tactic(m));
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tactic * new_sat = mk_new_sat_tactic(m);
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#endif
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tactic * st = using_params(and_then(preamble_st,
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