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restructure maxsmt solvers, flatten weighted/non-weighted versions, fix bugs and simplify mus/max-res
Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner
parent
5e9bf2ef53
commit
9f1b2ccfc4
10 changed files with 492 additions and 498 deletions
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@ -1,7 +1,21 @@
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/**
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MaxRes (weighted) max-sat algorithm by Nina and Bacchus, AAAI 2014.
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/*++
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Copyright (c) 2014 Microsoft Corporation
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Module Name:
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maxsres.cpp
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Abstract:
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*/
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MaxRes (weighted) max-sat algorithm by Nina and Bacchus, AAAI 2014.
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Author:
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Nikolaj Bjorner (nbjorner) 2014-20-7
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Notes:
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--*/
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#include "solver.h"
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#include "maxsmt.h"
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@ -11,7 +25,8 @@
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using namespace opt;
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struct maxres::imp {
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class maxres : public maxsmt_solver_base {
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struct info {
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app* m_cls;
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rational m_weight;
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@ -19,31 +34,25 @@ struct maxres::imp {
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m_cls(cls), m_weight(w) {}
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info(): m_cls(0) {}
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};
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ast_manager& m;
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solver& s;
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expr_ref_vector m_B;
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expr_ref_vector m_D;
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expr_ref_vector m_asms;
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model_ref m_model;
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expr_ref_vector m_soft_constraints;
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volatile bool m_cancel;
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rational m_lower;
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rational m_upper;
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obj_map<expr, info> m_asm2info;
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ptr_vector<expr> m_new_core;
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mus m_mus;
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expr_ref_vector m_trail;
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imp(ast_manager& m, solver& s, expr_ref_vector& soft_constraints, vector<rational> const& weights):
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m(m), s(s), m_B(m), m_D(m), m_asms(m), m_soft_constraints(m),
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m_cancel(false),
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m_mus(s, m),
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public:
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maxres(ast_manager& m, opt_solver* s, params_ref& p,
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vector<rational> const& ws, expr_ref_vector const& soft):
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maxsmt_solver_base(s, m, p, ws, soft),
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m_B(m), m_asms(m),
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m_mus(m_s, m),
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m_trail(m)
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{
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// TBD: this introduces an assertion to solver.
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init_soft(weights, soft_constraints);
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}
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virtual ~maxres() {}
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bool is_literal(expr* l) {
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return
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is_uninterp_const(l) ||
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@ -60,9 +69,9 @@ struct maxres::imp {
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asum = e;
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}
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else {
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asum = m.mk_fresh_const("soft", m.mk_bool_sort());
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asum = mk_fresh_bool("soft");
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fml = m.mk_iff(asum, e);
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s.assert_expr(fml);
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m_s->assert_expr(fml);
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}
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new_assumption(asum, cls, w);
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m_upper += w;
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@ -78,28 +87,35 @@ struct maxres::imp {
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lbool operator()() {
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expr_ref fml(m);
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ptr_vector<expr> core;
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solver::scoped_push _sc(s);
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solver::scoped_push _sc(*m_s.get());
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init();
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init_local();
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while (true) {
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TRACE("opt",
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display_vec(tout, m_asms.size(), m_asms.c_ptr());
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s.display(tout);
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m_s->display(tout);
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tout << "\n";
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display(tout);
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);
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lbool is_sat = s.check_sat(m_asms.size(), m_asms.c_ptr());
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lbool is_sat = m_s->check_sat(m_asms.size(), m_asms.c_ptr());
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if (m_cancel) {
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return l_undef;
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}
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switch (is_sat) {
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case l_true:
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s.get_model(m_model);
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m_s->get_model(m_model);
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for (unsigned i = 0; i < m_soft.size(); ++i) {
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expr_ref tmp(m);
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VERIFY(m_model->eval(m_soft[i].get(), tmp));
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m_assignment[i] = m.is_true(tmp);
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}
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m_upper = m_lower;
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return l_true;
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case l_undef:
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return l_undef;
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default:
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core.reset();
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s.get_unsat_core(core);
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m_s->get_unsat_core(core);
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TRACE("opt", display_vec(tout << "core: ", core.size(), core.c_ptr()););
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SASSERT(!core.empty());
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is_sat = minimize_core(core);
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@ -115,7 +131,7 @@ struct maxres::imp {
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TRACE("opt", display_vec(tout << "minimized core: ", core.size(), core.c_ptr()););
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max_resolve(core, w);
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fml = m.mk_not(m.mk_and(m_B.size(), m_B.c_ptr()));
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s.assert_expr(fml);
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m_s->assert_expr(fml);
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m_lower += w;
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break;
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}
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@ -192,31 +208,33 @@ struct maxres::imp {
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void max_resolve(ptr_vector<expr>& core, rational const& w) {
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SASSERT(!core.empty());
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expr_ref fml(m), asum(m);
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app_ref cls(m);
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app_ref cls(m), d(m);
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m_B.reset();
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m_D.reset();
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m_D.resize(core.size());
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m_B.append(core.size(), core.c_ptr());
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m_D[core.size()-1] = m.mk_false();
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d = m.mk_true();
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//
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// d_{sz-1} := false
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// d_i := (!core_{i+1} or d_{i+1}) for i = 0...sz-2
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// soft (!d_i or core_i)
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//
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for (unsigned i = core.size()-1; i > 0; ) {
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--i;
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expr* d_i1 = m_D[i+1].get();
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expr* b_i = m_B[i].get();
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expr* b_i1 = m_B[i+1].get();
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m_D[i] = m.mk_implies(b_i1, d_i1);
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expr* d_i = m_D[i].get();
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asum = m.mk_fresh_const("a", m.mk_bool_sort());
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cls = m.mk_implies(d_i, b_i);
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// d_0 := true
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// d_i := b_{i-1} and d_{i-1} for i = 1...sz-1
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// soft (b_i or !d_i)
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// == (b_i or !(!b_{i-1} or d_{i-1}))
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// == (b_i or b_0 & b_1 & ... & b_{i-1})
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//
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// Soft constraint is satisfied if previous soft constraint
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// holds or if it is the first soft constraint to fail.
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//
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// Soundness of this rule can be established using MaxRes
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//
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for (unsigned i = 1; i < core.size(); ++i) {
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expr* b_i = m_B[i-1].get();
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expr* b_i1 = m_B[i].get();
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d = m.mk_and(b_i, d);
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asum = mk_fresh_bool("a");
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cls = m.mk_or(b_i1, d);
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fml = m.mk_iff(asum, cls);
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cls = mk_cls(cls);
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m_trail.push_back(cls);
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new_assumption(asum, cls, w);
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s.assert_expr(fml);
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m_s->assert_expr(fml);
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}
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}
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@ -262,77 +280,25 @@ struct maxres::imp {
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}
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}
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rational get_lower() const {
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return m_lower;
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}
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rational get_upper() const {
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return m_upper;
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}
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bool get_assignment(unsigned index) const {
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expr_ref tmp(m);
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VERIFY(m_model->eval(m_soft_constraints[index], tmp));
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return m.is_true(tmp);
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}
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void set_cancel(bool f) {
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m_cancel = f;
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virtual void set_cancel(bool f) {
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maxsmt_solver_base::set_cancel(f);
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m_mus.set_cancel(f);
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}
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void collect_statistics(statistics& st) const {
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}
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void get_model(model_ref& mdl) {
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mdl = m_model;
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}
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void updt_params(params_ref& p) {
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;
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}
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void init_soft(vector<rational> const& weights, expr_ref_vector const& soft) {
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m_soft_constraints.reset();
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void init_local() {
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m_upper.reset();
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m_lower.reset();
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m_asm2info.reset();
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m_trail.reset();
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m_soft_constraints.append(soft);
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for (unsigned i = 0; i < m_soft_constraints.size(); ++i) {
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add_soft(m_soft_constraints[i].get(), weights[i]);
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for (unsigned i = 0; i < m_soft.size(); ++i) {
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add_soft(m_soft[i].get(), m_weights[i]);
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}
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}
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};
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maxres::maxres(ast_manager& m, solver& s, expr_ref_vector& soft_constraints, vector<rational> const& weights) {
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m_imp = alloc(imp, m, s, soft_constraints, weights);
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opt::maxsmt_solver_base* opt::mk_maxres(ast_manager& m, opt_solver* s, params_ref& p,
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vector<rational> const& ws, expr_ref_vector const& soft) {
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return alloc(maxres, m, s, p, ws, soft);
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}
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maxres::~maxres() {
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dealloc(m_imp);
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}
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lbool maxres::operator()() {
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return (*m_imp)();
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}
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rational maxres::get_lower() const {
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return m_imp->get_lower();
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}
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rational maxres::get_upper() const {
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return m_imp->get_upper();
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}
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bool maxres::get_assignment(unsigned index) const {
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return m_imp->get_assignment(index);
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}
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void maxres::set_cancel(bool f) {
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m_imp->set_cancel(f);
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}
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void maxres::collect_statistics(statistics& st) const {
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m_imp->collect_statistics(st);
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}
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void maxres::get_model(model_ref& mdl) {
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m_imp->get_model(mdl);
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}
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void maxres::updt_params(params_ref& p) {
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m_imp->updt_params(p);
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}
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