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Merge branch 'opt' of https://github.com/NikolajBjorner/z3 into opt

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This commit is contained in:
Miguel Angelo Da Terra Neves 2017-12-01 11:02:35 -08:00
commit 2e042a8bea
13 changed files with 304 additions and 158 deletions
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106
src/sat/sat_lookahead.cpp
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@ -20,6 +20,7 @@ Notes:
#include "sat/sat_solver.h"
#include "sat/sat_extension.h"
#include "sat/sat_lookahead.h"
#include "sat/sat_scc.h"
#include "util/union_find.h"
namespace sat {
@ -2013,6 +2014,11 @@ namespace sat {
return true;
}
void lookahead::update_cube_statistics(statistics& st) {
st.update("lh cube cutoffs", m_cube_state.m_cutoffs);
st.update("lh cube conflicts", m_cube_state.m_conflicts);
}
lbool lookahead::cube(bool_var_vector const& vars, literal_vector& lits, unsigned backtrack_level) {
scoped_ext _scoped_ext(*this);
lits.reset();
@ -2031,6 +2037,7 @@ namespace sat {
unsigned depth = 0;
unsigned init_trail = m_trail.size();
m_cube_state.reset_stats();
if (!is_first) {
goto pick_up_work;
}
@ -2041,8 +2048,9 @@ namespace sat {
inc_istamp();
if (inconsistent()) {
TRACE("sat", tout << "inconsistent: " << m_cube_state.m_cube << "\n";);
m_cube_state.m_freevars_threshold = m_freevars.size();
if (!backtrack(m_cube_state.m_cube, m_cube_state.m_is_decision)) return l_false;
m_cube_state.m_freevars_threshold = m_freevars.size();
m_cube_state.inc_conflict();
if (!backtrack(m_cube_state.m_cube, m_cube_state.m_is_decision)) return l_false;
continue;
}
pick_up_work:
@ -2062,6 +2070,7 @@ namespace sat {
(m_config.m_cube_cutoff == 0 && m_freevars.size() < m_cube_state.m_freevars_threshold)) {*/
m_cube_state.m_freevars_threshold *= (1.0 - pow(m_config.m_cube_fraction, depth));
set_conflict();
m_cube_state.inc_cutoff();
#if 0
// return cube of all literals, not just the ones in the main cube
lits.append(m_trail.size() - init_trail, m_trail.c_ptr() + init_trail);
@ -2308,15 +2317,86 @@ namespace sat {
void lookahead::add_hyper_binary() {
unsigned num_lits = m_s.num_vars() * 2;
#if 0
std::cout << "binary trail size: " << m_binary_trail.size() << "\n";
std::cout << "Are windfalls still on the trail at base level?\n";
unsigned num_lits = m_s.num_vars() * 2;
#endif
unsigned disconnected1 = 0;
unsigned disconnected2 = 0;
#if 1
typedef std::pair<unsigned, unsigned> u_pair;
hashtable<u_pair, pair_hash<unsigned_hash, unsigned_hash>, default_eq<u_pair> > imp;
for (unsigned idx = 0; idx < num_lits; ++idx) {
literal u = get_parent(to_literal(idx));
if (null_literal != u) {
for (watched const& w : m_s.m_watches[idx]) {
if (!w.is_binary_clause()) continue;
literal v = get_parent(w.get_literal());
if (null_literal != v) {
imp.insert(std::make_pair(u.index(), v.index()));
}
}
}
}
scc scc(m_s, m_s.m_params);
scc.init_big(true);
svector<std::pair<literal, literal>> candidates;
unsigned_vector bin_size(num_lits);
for (unsigned idx : m_binary_trail) {
bin_size[idx]++;
}
for (unsigned idx = 0; idx < num_lits; ++idx) {
literal u = to_literal(idx);
if (u != get_parent(u)) continue;
if (m_s.was_eliminated(u.var())) continue;
literal_vector const& lits = m_binary[idx];
for (unsigned sz = bin_size[idx]; sz > 0; --sz) {
literal v = lits[lits.size() - sz];
if (v != get_parent(v)) continue;
if (m_s.was_eliminated(v.var())) continue;
if (imp.contains(std::make_pair(u.index(), v.index()))) continue;
if (scc.reaches(u, v)) continue;
candidates.push_back(std::make_pair(u, v));
}
}
for (unsigned i = 0; i < 5; ++i) {
scc.init_big(true);
unsigned k = 0;
union_find_default_ctx ufctx;
union_find<union_find_default_ctx> uf(ufctx);
for (unsigned i = 0; i < num_lits; ++i) uf.mk_var();
for (unsigned j = 0; j < candidates.size(); ++j) {
literal u = candidates[j].first;
literal v = candidates[j].second;
if (!scc.reaches(u, v)) {
if (uf.find(u.index()) != uf.find(v.index())) {
++disconnected1;
uf.merge(u.index(), v.index());
uf.merge((~u).index(), (~v).index());
m_s.mk_clause(~u, v, true);
}
else {
candidates[k] = candidates[j];
++k;
}
}
}
std::cout << candidates.size() << " -> " << k << "\n";
if (k == candidates.size()) break;
candidates.shrink(k);
}
std::cout << "candidates: " << candidates.size() << "\n";
#endif
#if 0
union_find_default_ctx ufctx;
union_find<union_find_default_ctx> uf(ufctx);
for (unsigned i = 0; i < num_lits; ++i) uf.mk_var();
@ -2333,21 +2413,25 @@ namespace sat {
}
}
unsigned disconnected = 0;
for (unsigned i = 0; i < m_binary.size(); ++i) {
literal u = to_literal(i);
if (u == get_parent(u)) {
if (u == get_parent(u) && !m_s.was_eliminated(u.var())) {
for (literal v : m_binary[i]) {
if (v == get_parent(v) && uf.find(u.index()) != uf.find(v.index())) {
++disconnected;
if (v == get_parent(v) &&
!m_s.was_eliminated(v.var()) &&
uf.find(u.index()) != uf.find(v.index())) {
++disconnected2;
uf.merge(u.index(), v.index());
m_s.mk_clause(~u, v, true);
// m_s.mk_clause(~u, v, true);
}
}
}
}
IF_VERBOSE(10, verbose_stream() << "(sat-lookahead :bca " << disconnected << ")\n";);
m_stats.m_bca += disconnected;
#endif
IF_VERBOSE(10, verbose_stream() << "(sat-lookahead :bca " << disconnected1 << " " << disconnected2 << ")\n";);
//IF_VERBOSE(10, verbose_stream() << "(sat-lookahead :bca " << disconnected << ")\n";);
//m_stats.m_bca += disconnected;
}
void lookahead::normalize_parents() {