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z3-z3-4.12.6.src.opt.maxsmt.cpp Maven / Gradle / Ivy
/*++
Copyright (c) 2013 Microsoft Corporation
Module Name:
maxsmt.cpp
Abstract:
MaxSMT optimization context.
Author:
Nikolaj Bjorner (nbjorner) 2013-11-7
Notes:
--*/
#include
#include "util/uint_set.h"
#include "ast/ast_pp.h"
#include "ast/ast_util.h"
#include "ast/pb_decl_plugin.h"
#include "opt/maxsmt.h"
#include "opt/maxcore.h"
#include "opt/maxlex.h"
#include "opt/wmax.h"
#include "opt/opt_params.hpp"
#include "opt/opt_context.h"
#include "opt/opt_preprocess.h"
#include "smt/theory_wmaxsat.h"
#include "smt/theory_pb.h"
namespace opt {
maxsmt_solver_base::maxsmt_solver_base(maxsat_context& c, vector& s, unsigned index):
m(c.get_manager()),
m_c(c),
m_index(index),
m_soft(s),
m_assertions(m),
m_trail(m) {
c.get_base_model(m_model);
SASSERT(m_model);
updt_params(c.params());
}
void maxsmt_solver_base::updt_params(params_ref& p) {
m_params.copy(p);
}
void maxsmt_solver_base::reset_upper() {
m_upper = m_lower;
for (soft& s : m_soft)
m_upper += s.weight;
}
solver& maxsmt_solver_base::s() {
return m_c.get_solver();
}
void maxsmt_solver_base::commit_assignment() {
expr_ref tmp(m);
expr_ref_vector fmls(m);
rational k(0), cost(0);
vector weights;
for (soft const& s : m_soft) {
if (s.is_true()) {
k += s.weight;
}
else {
cost += s.weight;
}
weights.push_back(s.weight);
fmls.push_back(s.s);
}
pb_util pb(m);
tmp = pb.mk_ge(weights.size(), weights.data(), fmls.data(), k);
TRACE("opt", tout << "cost: " << cost << "\n" << tmp << "\n";);
s().assert_expr(tmp);
}
bool maxsmt_solver_base::init() {
m_lower.reset();
m_upper.reset();
for (soft& s : m_soft) {
s.set_value(m.is_true(s.s));
if (!s.is_true())
m_upper += s.weight;
}
// return true;
preprocess pp(s());
rational lower(0);
bool r = pp(m_soft, lower);
m_c.add_offset(m_index, lower);
m_upper -= lower;
TRACE("opt",
tout << "lower " << lower << " upper: " << m_upper << " assignments: ";
for (soft& s : m_soft) tout << (s.is_true()?"T":"F");
tout << "\n";);
return r;
}
void maxsmt_solver_base::set_mus(bool f) {
params_ref p;
p.set_bool("minimize_core", f);
// p.set_bool("minimize_core_partial", f);
s().updt_params(p);
}
void maxsmt_solver_base::enable_sls(bool force) {
m_c.enable_sls(force);
}
app* maxsmt_solver_base::mk_fresh_bool(char const* name) {
app* result = m.mk_fresh_const(name, m.mk_bool_sort());
m_c.fm().hide(result);
return result;
}
smt::theory_wmaxsat* maxsmt_solver_base::get_wmax_theory() const {
smt::theory_id th_id = m.get_family_id("weighted_maxsat");
smt::theory* th = m_c.smt_context().get_theory(th_id);
if (th) {
return dynamic_cast(th);
}
else {
return nullptr;
}
}
smt::theory_wmaxsat* maxsmt_solver_base::ensure_wmax_theory() {
smt::theory_wmaxsat* wth = get_wmax_theory();
if (wth) {
wth->reset_local();
}
else {
wth = alloc(smt::theory_wmaxsat, m_c.smt_context(), m, m_c.fm());
m_c.smt_context().register_plugin(wth);
}
smt::theory_id th_pb = m.get_family_id("pb");
smt::theory_pb* pb = dynamic_cast(m_c.smt_context().get_theory(th_pb));
if (!pb) {
theory_pb_params params;
pb = alloc(smt::theory_pb, m_c.smt_context());
m_c.smt_context().register_plugin(pb);
}
return wth;
}
maxsmt_solver_base::scoped_ensure_theory::scoped_ensure_theory(maxsmt_solver_base& s) {
m_wth = s.ensure_wmax_theory();
}
maxsmt_solver_base::scoped_ensure_theory::~scoped_ensure_theory() {
if (m_wth) {
m_wth->reset_local();
}
}
smt::theory_wmaxsat& maxsmt_solver_base::scoped_ensure_theory::operator()() { return *m_wth; }
void maxsmt_solver_base::trace_bounds(char const * solver) {
IF_VERBOSE(1,
rational l = m_c.adjust(m_index, m_lower);
rational u = m_c.adjust(m_index, m_upper);
if (l > u) std::swap(l, u);
verbose_stream() << "(opt." << solver << " [" << l << ":" << u << "])\n";);
}
maxsmt::maxsmt(maxsat_context& c, unsigned index):
m(c.get_manager()), m_c(c), m_index(index), m_answer(m) {}
lbool maxsmt::operator()(bool committed) {
lbool is_sat = l_undef;
m_msolver = nullptr;
opt_params optp(m_params);
symbol const& maxsat_engine = m_c.maxsat_engine();
IF_VERBOSE(1, verbose_stream() << "(maxsmt)\n";);
TRACE("opt_verbose", s().display(tout << "maxsmt\n") << "\n";);
if (!committed && optp.maxlex_enable() && is_maxlex(m_soft))
m_msolver = mk_maxlex(m_c, m_index, m_soft);
else if (m_soft.empty() || maxsat_engine == symbol("maxres") || maxsat_engine == symbol::null)
m_msolver = mk_maxres(m_c, m_index, m_soft);
else if (maxsat_engine == symbol("maxres-bin"))
m_msolver = mk_maxres_binary(m_c, m_index, m_soft);
else if (maxsat_engine == symbol("rc2"))
m_msolver = mk_rc2(m_c, m_index, m_soft);
else if (maxsat_engine == symbol("rc2bin"))
m_msolver = mk_rc2bin(m_c, m_index, m_soft);
else if (maxsat_engine == symbol("pd-maxres"))
m_msolver = mk_primal_dual_maxres(m_c, m_index, m_soft);
else if (maxsat_engine == symbol("wmax"))
m_msolver = mk_wmax(m_c, m_soft, m_index);
else if (maxsat_engine == symbol("sortmax"))
m_msolver = mk_sortmax(m_c, m_soft, m_index);
else {
auto str = maxsat_engine.str();
warning_msg("solver %s is not recognized, using default 'maxres'", str.c_str());
m_msolver = mk_maxres(m_c, m_index, m_soft);
}
if (m_msolver) {
m_msolver->updt_params(m_params);
is_sat = l_undef;
try {
is_sat = (*m_msolver)();
}
catch (z3_exception& ex) {
IF_VERBOSE(1, verbose_stream() << ex.msg() << "\n");
is_sat = l_undef;
}
if (is_sat != l_false) {
m_msolver->get_model(m_model, m_labels);
}
}
IF_VERBOSE(5, verbose_stream() << "is-sat: " << is_sat << "\n";
if (is_sat == l_true) {
verbose_stream() << "Satisfying soft constraints\n";
display_answer(verbose_stream());
});
DEBUG_CODE(if (is_sat == l_true) verify_assignment(););
return is_sat;
}
void maxsmt::reset_upper() {
if (m_msolver) {
m_msolver->reset_upper();
m_upper = m_msolver->get_upper();
}
}
void maxsmt::verify_assignment() {
// TBD: have to use a different solver
// because we don't push local scope any longer.
return;
}
bool maxsmt::get_assignment(unsigned idx) const {
if (m_msolver) {
return m_msolver->get_assignment(idx);
}
else {
return true;
}
}
rational maxsmt::get_lower() const {
rational r = m_lower;
if (m_msolver) {
rational q = m_msolver->get_lower();
if (q > r) r = q;
}
return m_c.adjust(m_index, r);
}
rational maxsmt::get_upper() const {
rational r = m_upper;
if (m_msolver) {
rational q = m_msolver->get_upper();
if (q < r) r = q;
}
return m_c.adjust(m_index, r);
}
void maxsmt::update_lower(rational const& r) {
m_lower = r;
}
void maxsmt::update_upper(rational const& r) {
m_upper = r;
}
void maxsmt::get_model(model_ref& mdl, svector& labels) {
mdl = m_model.get();
labels = m_labels;
}
void maxsmt::commit_assignment() {
if (m_msolver) {
m_msolver->commit_assignment();
}
}
void maxsmt::add(expr* f, rational const& w) {
TRACE("opt", tout << mk_pp(f, m) << " weight: " << w << "\n";);
SASSERT(m.is_bool(f));
SASSERT(w.is_pos());
unsigned index = 0;
if (m_soft_constraint_index.find(f, index)) {
m_soft[index].weight += w;
}
else {
m_soft_constraint_index.insert(f, m_soft.size());
m_soft.push_back(soft(expr_ref(f, m), w, false));
}
m_upper += w;
}
struct cmp_first {
bool operator()(std::pair const& x, std::pair const& y) const {
return x.second < y.second;
}
};
void maxsmt::display_answer(std::ostream& out) const {
unsigned idx = 0;
for (auto const & [_e, w, t] : m_soft) {
expr* e = _e.get();
bool is_not = m.is_not(e, e);
out << w << ": " << mk_pp(e, m)
<< ((is_not != get_assignment(idx))?" |-> true ":" |-> false ")
<< "\n";
++idx;
}
}
bool maxsmt::is_maxsat_problem(vector const& ws) const {
for (unsigned i = 0; i < ws.size(); ++i) {
if (!ws[i].is_one()) {
return false;
}
}
return true;
}
void maxsmt::updt_params(params_ref& p) {
m_params.append(p);
if (m_msolver)
m_msolver->updt_params(p);
}
void maxsmt::collect_statistics(statistics& st) const {
if (m_msolver)
m_msolver->collect_statistics(st);
}
solver& maxsmt::s() {
return m_c.get_solver();
}
void maxsmt::model_updated(model* mdl) {
m_c.model_updated(mdl);
}
class solver_maxsat_context : public maxsat_context {
params_ref m_params;
solver_ref m_solver;
model_ref m_model;
ref m_fm;
symbol m_maxsat_engine;
vector m_offsets;
public:
solver_maxsat_context(params_ref& p, solver* s, model * m):
m_params(p),
m_solver(s),
m_model(m),
m_fm(alloc(generic_model_converter, s->get_manager(), "maxsmt")) {
opt_params _p(p);
m_maxsat_engine = _p.maxsat_engine();
}
generic_model_converter& fm() override { return *m_fm.get(); }
bool sat_enabled() const override { return false; }
solver& get_solver() override { return *m_solver.get(); }
ast_manager& get_manager() const override { return m_solver->get_manager(); }
params_ref& params() override { return m_params; }
void enable_sls(bool force) override { } // no op
symbol const& maxsat_engine() const override { return m_maxsat_engine; }
void get_base_model(model_ref& _m) override { _m = m_model; };
smt::context& smt_context() override {
throw default_exception("stand-alone maxsat context does not support wmax");
}
unsigned num_objectives() override { return 1; }
bool verify_model(unsigned id, model* mdl, rational const& v) override { return true; };
void set_model(model_ref& _m) override { m_model = _m; }
void model_updated(model* mdl) override { } // no-op
rational adjust(unsigned id, rational const& r) override {
m_offsets.reserve(id+1);
return r + m_offsets[id];
}
void add_offset(unsigned id, rational const& r) override {
m_offsets.reserve(id+1);
m_offsets[id] += r;
}
};
lbool maxsmt_wrapper::operator()(vector>& soft) {
solver_maxsat_context ctx(m_params, m_solver.get(), m_model.get());
maxsmt maxsmt(ctx, 0);
for (auto const& p : soft) {
maxsmt.add(p.first, p.second);
}
lbool r = maxsmt(true);
if (r == l_true) {
svector labels;
maxsmt.get_model(m_model, labels);
// TBD: is m_fm applied or not?
unsigned j = 0;
for (auto const& p : soft) {
if (m_model->is_true(p.first)) {
soft[j++] = p;
}
}
soft.shrink(j);
}
return r;
}
};
