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reworking pd-maxres

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2015-08-26 16:33:53 -07:00
parent af9143b64a
commit 7c47809973
3 changed files with 61 additions and 33 deletions
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90
src/sat/sat_solver.cpp
View file

@ -926,7 +926,7 @@ namespace sat {
svector<literal> blocker;
if (!init_weighted_assumptions(num_lits, lits, weights, max_weight, blocker)) {
pop_to_base_level();
mk_clause(blocker.size(), blocker.c_ptr());
mk_clause(blocker.size(), blocker.c_ptr());
goto retry_init_assumptions;
}
}
@ -948,68 +948,93 @@ namespace sat {
flet<bool> _min2(m_config.m_minimize_core_partial, false);
m_conflict_lvl = m_scope_lvl;
resolve_conflict_for_unsat_core();
m_assumptions.pop_back();
}
bool solver::init_weighted_assumptions(unsigned num_lits, literal const* lits, double const* weights, double max_weight,
svector<literal>& blocker) {
double weight = 0;
blocker.reset();
svector<literal> min_core;
bool min_core_valid = false;
for (unsigned i = 0; !inconsistent() && i < num_lits; ++i) {
literal lit = lits[i];
SASSERT(is_external(lit.var()));
m_assumption_set.insert(lit);
TRACE("sat", tout << "propagate: " << lit << " " << value(lit) << "\n";);
SASSERT(m_scope_lvl == 1);
switch(value(lit)) {
case l_undef:
m_assumption_set.insert(lit);
m_assumptions.push_back(lit);
assign(lit, justification());
propagate(false);
if (inconsistent()) {
resolve_weighted();
pop(1);
push();
for (unsigned j = 0; j < m_assumptions.size(); ++j) {
assign(m_assumptions[j], justification());
blocker.reset();
// next time around, the negation of the literal will be implied.
for (unsigned j = 0; j < m_core.size(); ++j) {
blocker.push_back(~m_core[j]);
}
propagate(false);
goto post_process_false;
IF_VERBOSE(1,
verbose_stream() << "undef: " << lit << " : " << blocker << "\n";
verbose_stream() << m_assumptions << "\n";);
// TBD: avoid redoing assignments, bail out for a full assignment.
return false;
}
blocker.push_back(~lit);
break;
case l_false: {
case l_false:
m_assumption_set.insert(lit);
m_assumptions.push_back(lit);
SASSERT(!inconsistent());
set_conflict(justification(), ~lit);
resolve_weighted();
goto post_process_false;
}
weight += weights[i];
TRACE("sat", tout << "core: " << m_core << "\nassumptions: " << m_assumptions << "\n";);
SASSERT(m_core.size() <= m_assumptions.size());
SASSERT(m_assumptions.size() <= i+1);
if (m_core.size() <= 3) {
m_inconsistent = true;
TRACE("opt", tout << "found small core: " << m_core << "\n";);
IF_VERBOSE(1, verbose_stream() << "small core: " << m_core << "\n";);
return true;
}
if (weight >= max_weight) {
++m_stats.m_blocked_corr_sets;
TRACE("opt", tout << "blocking soft correction set: " << blocker << "\n";);
// block the current correction set candidate.
IF_VERBOSE(1, verbose_stream() << "blocking " << blocker << "\n";);
return false;
}
VERIFY(m_assumptions.back() == m_assumption_set.pop());
m_assumptions.pop_back();
m_inconsistent = false;
if (!min_core_valid || m_core.size() < min_core.size()) {
min_core.reset();
min_core.append(m_core);
}
blocker.push_back(lit);
break;
case l_true:
break;
}
continue;
post_process_false:
weight += weights[i];
blocker.push_back(lit);
TRACE("sat", tout << "core: " << m_core << "\nassumptions: " << m_assumptions << "\n";);
SASSERT(m_core.size() <= m_assumptions.size() + 1);
SASSERT(m_assumptions.size() <= i);
if (m_core.size() <= 3) {
m_inconsistent = true;
TRACE("opt", tout << "found small core: " << m_core << "\n";);
return true;
}
m_inconsistent = false;
if (weight >= max_weight) {
++m_stats.m_blocked_corr_sets;
TRACE("opt", tout << "blocking soft correction set: " << blocker.size() << "\n";);
// block the current correction set candidate.
return false;
}
}
TRACE("sat", tout << "initialized\n";);
IF_VERBOSE(1, verbose_stream() << blocker << " - " << min_core << "\n";);
if (min_core_valid && blocker.size() > min_core.size()) {
pop_to_base_level();
m_assumption_set.reset();
m_assumptions.reset();
for (unsigned i = 0; i < min_core.size(); ++i) {
literal lit = min_core[i];
SASSERT(is_external(lit.var()));
m_assumption_set.insert(lit);
m_assumptions.push_back(lit);
assign(lit, justification());
}
propagate(false);
SASSERT(inconsistent());
}
return true;
}
@ -2531,6 +2556,7 @@ namespace sat {
//
// -----------------------
bool solver::check_invariant() const {
if (m_cancel) return true;
integrity_checker checker(*this);
SASSERT(checker());
return true;

3
src/sat/sat_solver.h
View file

@ -297,7 +297,8 @@ namespace sat {
lbool bounded_search();
void init_search();
void init_assumptions(unsigned num_lits, literal const* lits, double const* weights, double max_weight);
bool init_weighted_assumptions(unsigned num_lits, literal const* lits, double const* weights, double max_weight, svector<literal>& blocker);
bool init_weighted_assumptions(unsigned num_lits, literal const* lits, double const* weights,
double max_weight, svector<literal>& blocker);
void resolve_weighted();
void reinit_assumptions();
bool tracking_assumptions() const;

1
src/sat/sat_types.h
View file

@ -228,6 +228,7 @@ namespace sat {
return result;
}
void insert(literal l) { m_set.insert(l.index()); }
literal pop() { return to_literal(m_set.erase()); }
bool contains(literal l) const { return m_set.contains(l.index()); }
bool empty() const { return m_set.empty(); }
unsigned size() const { return m_set.size(); }