z3-z3-4.13.0.src.test.cnf_backbones.cpp Maven / Gradle / Ivy
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/*++
Copyright (c) 2017 Microsoft Corporation
--*/
#include
#include
#include
#include "util/timeout.h"
#include "util/rlimit.h"
#include "sat/dimacs.h"
#include "sat/sat_solver.h"
#include "util/gparams.h"
static sat::solver * g_solver = nullptr;
static clock_t g_start_time;
static void display_statistics() {
clock_t end_time = clock();
if (g_solver) {
std::cout.flush();
std::cerr.flush();
statistics st;
g_solver->collect_statistics(st);
st.update("total time", ((static_cast(end_time) - static_cast(g_start_time)) / CLOCKS_PER_SEC));
st.display_smt2(std::cout);
}
}
static void on_timeout() {
display_statistics();
exit(0);
}
static void STD_CALL on_ctrl_c(int) {
signal (SIGINT, SIG_DFL);
display_statistics();
raise(SIGINT);
}
#if 0
static void display_model(sat::solver const & s) {
sat::model const & m = s.get_model();
for (unsigned i = 1; i < m.size(); i++) {
switch (m[i]) {
case l_false: std::cout << "-" << i << " "; break;
case l_undef: break;
case l_true: std::cout << i << " "; break;
}
}
std::cout << "\n";
}
#endif
static void display_status(lbool r) {
switch (r) {
case l_true:
std::cout << "sat\n";
break;
case l_undef:
std::cout << "unknown\n";
break;
case l_false:
std::cout << "unsat\n";
break;
}
}
static void track_clause(sat::solver& dst,
sat::literal_vector& lits,
sat::literal_vector& assumptions,
vector& tracking_clauses) {
sat::literal lit = sat::literal(dst.mk_var(true, false), false);
tracking_clauses.set(lit.var(), lits);
lits.push_back(~lit);
dst.mk_clause(lits.size(), lits.data());
assumptions.push_back(lit);
}
static void track_clauses(sat::solver const& src,
sat::solver& dst,
sat::literal_vector& assumptions,
vector& tracking_clauses) {
for (sat::bool_var v = 0; v < src.num_vars(); ++v) {
dst.mk_var(false, true);
}
sat::literal_vector lits;
sat::literal lit;
sat::clause * const * it = src.begin_clauses();
sat::clause * const * end = src.end_clauses();
svector bin_clauses;
src.collect_bin_clauses(bin_clauses, false, false);
tracking_clauses.reserve(2*src.num_vars() + static_cast(end - it) + bin_clauses.size());
for (sat::bool_var v = 1; v < src.num_vars(); ++v) {
if (src.value(v) != l_undef) {
bool sign = src.value(v) == l_false;
lits.reset();
lits.push_back(sat::literal(v, sign));
track_clause(dst, lits, assumptions, tracking_clauses);
}
}
for (; it != end; ++it) {
lits.reset();
sat::clause& cls = *(*it);
lits.append(static_cast(cls.end()-cls.begin()), cls.begin());
track_clause(dst, lits, assumptions, tracking_clauses);
}
for (unsigned i = 0; i < bin_clauses.size(); ++i) {
lits.reset();
lits.push_back(bin_clauses[i].first);
lits.push_back(bin_clauses[i].second);
track_clause(dst, lits, assumptions, tracking_clauses);
}
}
static void prune_unfixed(sat::literal_vector& lambda, sat::model const& m) {
for (unsigned i = 0; i < lambda.size(); ++i) {
if ((m[lambda[i].var()] == l_false) != lambda[i].sign()) {
lambda[i] = lambda.back();
lambda.pop_back();
--i;
}
}
}
// Algorithm 7: Corebased Algorithm with Chunking
static void back_remove(sat::literal_vector& lits, sat::literal l) {
for (unsigned i = lits.size(); i > 0; ) {
--i;
if (lits[i] == l) {
lits[i] = lits.back();
lits.pop_back();
return;
}
}
std::cout << "UNREACHABLE\n";
}
static void brute_force_consequences(sat::solver& s, sat::literal_vector const& asms, sat::literal_vector const& gamma, sat::literal_vector& backbones) {
for (unsigned i = 0; i < gamma.size(); ++i) {
sat::literal nlit = ~gamma[i];
sat::literal_vector asms1(asms);
asms1.push_back(nlit);
lbool r = s.check(asms1.size(), asms1.data());
if (r == l_false) {
backbones.push_back(gamma[i]);
}
}
}
static lbool core_chunking(sat::solver& s, sat::bool_var_vector& vars, sat::literal_vector const& asms, vector& conseq, unsigned K) {
lbool r = s.check(asms.size(), asms.data());
if (r != l_true) {
return r;
}
sat::model const & m = s.get_model();
sat::literal_vector lambda, backbones;
for (unsigned i = 0; i < vars.size(); i++) {
lambda.push_back(sat::literal(vars[i], m[vars[i]] == l_false));
}
while (!lambda.empty()) {
IF_VERBOSE(1, verbose_stream() << "(sat-backbone-core " << lambda.size() << " " << backbones.size() << ")\n";);
unsigned k = std::min(K, lambda.size());
sat::literal_vector gamma, omegaN;
for (unsigned i = 0; i < k; ++i) {
sat::literal l = lambda[lambda.size() - i - 1];
gamma.push_back(l);
omegaN.push_back(~l);
}
while (true) {
sat::literal_vector asms1(asms);
asms1.append(omegaN);
r = s.check(asms1.size(), asms1.data());
if (r == l_true) {
IF_VERBOSE(1, verbose_stream() << "(sat) " << omegaN << "\n";);
prune_unfixed(lambda, s.get_model());
break;
}
sat::literal_vector const& core = s.get_core();
sat::literal_vector occurs;
IF_VERBOSE(1, verbose_stream() << "(core " << core.size() << ")\n";);
for (unsigned i = 0; i < omegaN.size(); ++i) {
if (core.contains(omegaN[i])) {
occurs.push_back(omegaN[i]);
}
}
if (occurs.size() == 1) {
sat::literal lit = occurs.back();
sat::literal nlit = ~lit;
backbones.push_back(~lit);
back_remove(lambda, ~lit);
back_remove(gamma, ~lit);
s.mk_clause(1, &nlit);
}
for (unsigned i = 0; i < omegaN.size(); ++i) {
if (occurs.contains(omegaN[i])) {
omegaN[i] = omegaN.back();
omegaN.pop_back();
--i;
}
}
if (omegaN.empty() && occurs.size() > 1) {
brute_force_consequences(s, asms, gamma, backbones);
for (unsigned i = 0; i < gamma.size(); ++i) {
back_remove(lambda, gamma[i]);
}
break;
}
}
}
for (unsigned i = 0; i < backbones.size(); ++i) {
sat::literal_vector cons;
cons.push_back(backbones[i]);
conseq.push_back(cons);
}
return l_true;
}
static void cnf_backbones(bool use_chunk, char const* file_name) {
g_start_time = clock();
register_on_timeout_proc(on_timeout);
signal(SIGINT, on_ctrl_c);
params_ref p = gparams::get_module("sat");
p.set_bool("produce_models", true);
reslimit limit;
sat::solver solver(p, limit);
sat::solver solver2(p, limit);
g_solver = &solver;
if (file_name) {
std::ifstream in(file_name);
if (in.bad() || in.fail()) {
std::cerr << "(error \"failed to open file '" << file_name << "'\")" << std::endl;
exit(ERR_OPEN_FILE);
}
if (!parse_dimacs(in, std::cerr, solver)) return;
}
else {
if (!parse_dimacs(std::cin, std::cerr, solver)) return;
}
IF_VERBOSE(20, solver.display_status(verbose_stream()););
vector conseq;
sat::bool_var_vector vars;
sat::literal_vector assumptions;
unsigned num_vars = solver.num_vars();
if (p.get_bool("dimacs.core", false)) {
g_solver = &solver2;
vector tracking_clauses;
track_clauses(solver, solver2, assumptions, tracking_clauses);
}
// remove this line to limit variables to exclude assumptions
num_vars = g_solver->num_vars();
for (unsigned i = 1; i < num_vars; ++i) {
vars.push_back(i);
g_solver->set_external(i);
}
lbool r;
if (use_chunk) {
r = core_chunking(*g_solver, vars, assumptions, conseq, 100);
}
else {
r = g_solver->get_consequences(assumptions, vars, conseq);
}
std::cout << vars.size() << " " << conseq.size() << "\n";
display_status(r);
display_statistics();
}
void tst_cnf_backbones(char ** argv, int argc, int& i) {
bool use_chunk = i + 1 < argc && argv[i + 1] == std::string("chunk");
if (use_chunk) ++i;
char const* file = "";
if (i + 1 < argc) {
file = argv[i + 1];
}
else {
file = argv[1];
}
cnf_backbones(use_chunk, file);
++i;
}