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fix autarky detection

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2017-03-31 13:16:04 -07:00
parent 6571aad440
commit c0188a7ec0
3 changed files with 87 additions and 26 deletions
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75
src/sat/sat_lookahead.h
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@ -220,7 +220,7 @@ namespace sat {
// ----------------------------------------
void add_binary(literal l1, literal l2) {
TRACE("sat", tout << "binary: " << l1 << " " << l2 << "\n";);
TRACE("sat", tout << "binary: " << l1 << " " << l2 << "\n";);
SASSERT(l1 != l2);
// don't add tautologies and don't add already added binaries
if (~l1 == l2) return;
@ -375,7 +375,7 @@ namespace sat {
progress = false;
float mean = sum / (float)(m_candidates.size() + 0.0001);
sum = 0;
for (unsigned i = 0; i < m_candidates.size(); ++i) {
for (unsigned i = 0; i < m_candidates.size() && m_candidates.size() >= max_num_cand * 2; ++i) {
if (m_candidates[i].m_rating >= mean) {
sum += m_candidates[i].m_rating;
}
@ -1133,11 +1133,14 @@ namespace sat {
m_search_mode = lookahead_mode::searching;
// convert windfalls to binary clauses.
if (!unsat) {
literal nlit = ~lit;
for (unsigned i = 0; i < m_wstack.size(); ++i) {
++m_stats.m_windfall_binaries;
literal l2 = m_wstack[i];
//update_prefix(~lit);
//update_prefix(m_wstack[i]);
add_binary(~lit, m_wstack[i]);
TRACE("sat", tout << "windfall: " << nlit << " " << l2 << "\n";);
add_binary(nlit, l2);
}
}
m_wstack.reset();
@ -1280,6 +1283,9 @@ namespace sat {
else {
TRACE("sat", tout << "propagating " << l << ": " << c << "\n";);
SASSERT(is_undef(c[0]));
DEBUG_CODE(for (unsigned i = 2; i < c.size(); ++i) {
SASSERT(is_false(c[i]));
});
*it2 = *it;
it2++;
propagated(c[0]);
@ -1354,7 +1360,7 @@ namespace sat {
TRACE("sat", tout << "lookahead: " << lit << " @ " << m_lookahead[i].m_offset << "\n";);
reset_wnb(lit);
push_lookahead1(lit, level);
do_double(lit, base);
//do_double(lit, base);
bool unsat = inconsistent();
pop_lookahead1(lit);
if (unsat) {
@ -1433,30 +1439,55 @@ namespace sat {
set_wnb(l, p == null_literal ? 0 : get_wnb(p));
}
void update_wnb(literal l, unsigned level) {
if (m_weighted_new_binaries == 0) {
{
scoped_level _sl(*this, level);
clause_vector::const_iterator it = m_full_watches[l.index()].begin(), end = m_full_watches[l.index()].end();
for (; it != end; ++it) {
clause& c = *(*it);
unsigned sz = c.size();
bool found = false;
for (unsigned i = 0; !found && i < sz; ++i) {
found = is_true(c[i]);
}
IF_VERBOSE(2, verbose_stream() << "skip autarky\n";);
if (!found) return;
bool check_autarky(literal l, unsigned level) {
// no propagations are allowed to reduce clauses.
clause_vector::const_iterator it = m_full_watches[l.index()].begin();
clause_vector::const_iterator end = m_full_watches[l.index()].end();
for (; it != end; ++it) {
clause& c = *(*it);
unsigned sz = c.size();
bool found = false;
for (unsigned i = 0; !found && i < sz; ++i) {
found = is_true(c[i]);
if (found) {
TRACE("sat", tout << c[i] << " is true in " << c << "\n";);
}
}
if (get_wnb(l) == 0) {
IF_VERBOSE(2, verbose_stream() << "skip autarky " << l << "\n";);
if (!found) return false;
}
//
// bail out if there is a pending binary propagation.
// In general, we would have to check, recursively that
// a binary propagation does not create reduced clauses.
//
literal_vector const& lits = m_binary[l.index()];
TRACE("sat", tout << l << ": " << lits << "\n";);
for (unsigned i = 0; i < lits.size(); ++i) {
literal l2 = lits[i];
if (is_true(l2)) continue;
SASSERT(!is_false(l2));
return false;
}
return true;
}
void update_wnb(literal l, unsigned level) {
if (m_weighted_new_binaries == 0) {
if (!check_autarky(l, level)) {
// skip
}
else if (get_wnb(l) == 0) {
++m_stats.m_autarky_propagations;
IF_VERBOSE(1, verbose_stream() << "(sat.lookahead autarky " << l << ")\n";);
TRACE("sat", tout << "autarky: " << l << " @ " << m_stamp[l.var()] << "\n";);
TRACE("sat", tout << "autarky: " << l << " @ " << m_stamp[l.var()]
<< " "
<< (!m_binary[l.index()].empty() || !m_full_watches[l.index()].empty()) << "\n";);
reset_wnb();
assign(l);
propagate();
propagate();
init_wnb();
}
else {