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Merge branch 'master' of https://github.com/Z3Prover/z3

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Nikolaj Bjorner 2017-04-30 10:23:05 -07:00
commit 5fcbf55216
31 changed files with 1029 additions and 185 deletions
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100
src/sat/sat_solver.cpp
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@ -3141,6 +3141,101 @@ namespace sat {
//
// -----------------------
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, vector<sat::literal_vector>& conseq) {
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.c_ptr());
if (r == l_false) {
conseq.push_back(s.get_core());
}
}
}
static lbool core_chunking(sat::solver& s, model const& m, sat::bool_var_vector const& vars, sat::literal_vector const& asms, vector<sat::literal_vector>& conseq, unsigned K) {
sat::literal_vector lambda;
for (unsigned i = 0; i < vars.size(); i++) {
lambda.push_back(sat::literal(i, m[vars[i]] == l_false));
}
while (!lambda.empty()) {
IF_VERBOSE(1, verbose_stream() << "(sat-backbone-core " << lambda.size() << " " << conseq.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);
lbool r = s.check(asms1.size(), asms1.c_ptr());
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;
conseq.push_back(core);
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, conseq);
for (unsigned i = 0; i < gamma.size(); ++i) {
back_remove(lambda, gamma[i]);
}
break;
}
}
}
return l_true;
}
lbool solver::get_consequences(literal_vector const& asms, bool_var_vector const& vars, vector<literal_vector>& conseq) {
literal_vector lits;
lbool is_sat = l_true;
@ -3163,6 +3258,9 @@ namespace sat {
default: break;
}
}
// is_sat = core_chunking(*this, mdl, vars, asms, conseq, 100);
is_sat = get_consequences(asms, lits, conseq);
set_model(mdl);
return is_sat;
@ -3310,7 +3408,7 @@ namespace sat {
propagate(false);
++num_resolves;
}
if (scope_lvl() == 1) {
if (false && scope_lvl() == 1) {
break;
}
}