From 7c47809973a2da7efed8fa91b40c3f83ceeae130 Mon Sep 17 00:00:00 2001
From: Nikolaj Bjorner <nbjorner@microsoft.com>
Date: Wed, 26 Aug 2015 16:33:53 -0700
Subject: [PATCH] reworking pd-maxres
Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
---
src/sat/sat_solver.cpp | 90 +++++++++++++++++++++++++++---------------
src/sat/sat_solver.h | 3 +-
src/sat/sat_types.h | 1 +
3 files changed, 61 insertions(+), 33 deletions(-)
diff --git a/src/sat/sat_solver.cpp b/src/sat/sat_solver.cpp
index 6755d1778..64eb10148 100644
--- a/src/sat/sat_solver.cpp
+++ b/src/sat/sat_solver.cpp
@@ -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;
diff --git a/src/sat/sat_solver.h b/src/sat/sat_solver.h
index 8c9c613c0..f8f3cd13b 100644
--- a/src/sat/sat_solver.h
+++ b/src/sat/sat_solver.h
@@ -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;
diff --git a/src/sat/sat_types.h b/src/sat/sat_types.h
index 2def82b80..c0c087e59 100644
--- a/src/sat/sat_types.h
+++ b/src/sat/sat_types.h
@@ -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(); }