mirrors/z3
3
0
Fork 0
mirror of https://github.com/Z3Prover/z3 synced 2025-05-11 09:44:43 +00:00
Code Activity

fix https://z3.codeplex.com/workitem/62

Browse source 
Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
This commit is contained in:
Leonardo de Moura 2013-11-04 11:57:29 -08:00
parent 8b10e13251
commit 825b72719c
2 changed files with 189 additions and 173 deletions
Download patch file Download diff file Expand all files Collapse all files

142
src/sat/sat_simplifier.cpp
View file

@ -9,7 +9,7 @@ Abstract:
SAT simplification procedures that use a "full" occurrence list:
Subsumption, Blocked Clause Removal, Variable Elimination, ...
Author:
@ -54,21 +54,21 @@ namespace sat {
m_use_list[l2.index()].erase(c);
}
}
simplifier::simplifier(solver & _s, params_ref const & p):
s(_s),
m_num_calls(0) {
updt_params(p);
reset_statistics();
}
simplifier::~simplifier() {
}
inline watch_list & simplifier::get_wlist(literal l) { return s.get_wlist(l); }
inline watch_list const & simplifier::get_wlist(literal l) const { return s.get_wlist(l); }
inline bool simplifier::is_external(bool_var v) const { return s.is_external(v); }
inline bool simplifier::was_eliminated(bool_var v) const { return s.was_eliminated(v); }
@ -78,7 +78,7 @@ namespace sat {
lbool simplifier::value(literal l) const { return s.value(l); }
inline void simplifier::checkpoint() { s.checkpoint(); }
void simplifier::register_clauses(clause_vector & cs) {
std::stable_sort(cs.begin(), cs.end(), size_lt());
clause_vector::iterator it = cs.begin();
@ -117,7 +117,7 @@ namespace sat {
SASSERT(s.get_wlist(~l1).contains(watched(l2, learned)));
s.get_wlist(~l1).erase(watched(l2, learned));
}
void simplifier::init_visited() {
m_visited.reset();
m_visited.resize(2*s.num_vars(), false);
@ -155,7 +155,7 @@ namespace sat {
if (!learned && (m_elim_blocked_clauses || m_elim_blocked_clauses_at == m_num_calls))
elim_blocked_clauses();
if (!learned)
m_num_calls++;
@ -180,6 +180,7 @@ namespace sat {
bool vars_eliminated = m_num_elim_vars > old_num_elim_vars;
if (!m_need_cleanup) {
TRACE("after_simplifier", tout << "skipping cleanup...\n";);
if (vars_eliminated) {
// must remove learned clauses with eliminated variables
cleanup_clauses(s.m_learned, true, true, learned_in_use_lists);
@ -189,6 +190,7 @@ namespace sat {
free_memory();
return;
}
TRACE("after_simplifier", tout << "cleanning watches...\n";);
cleanup_watches();
cleanup_clauses(s.m_learned, true, vars_eliminated, learned_in_use_lists);
cleanup_clauses(s.m_clauses, false, vars_eliminated, true);
@ -234,7 +236,7 @@ namespace sat {
s.del_clause(c);
continue;
}
if (learned && vars_eliminated) {
unsigned sz = c.size();
unsigned i;
@ -293,7 +295,7 @@ namespace sat {
mark_visited(c[i]);
}
}
void simplifier::unmark_all(clause const & c) {
unsigned sz = c.size();
for (unsigned i = 0; i < sz; i++)
@ -325,7 +327,7 @@ namespace sat {
*/
bool simplifier::subsumes1(clause const & c1, clause const & c2, literal & l) {
unsigned sz2 = c2.size();
for (unsigned i = 0; i < sz2; i++)
for (unsigned i = 0; i < sz2; i++)
mark_visited(c2[i]);
bool r = true;
@ -344,7 +346,7 @@ namespace sat {
}
}
for (unsigned i = 0; i < sz2; i++)
for (unsigned i = 0; i < sz2; i++)
unmark_visited(c2[i]);
return r;
}
@ -353,7 +355,7 @@ namespace sat {
\brief Return the clauses subsumed by c1 and the clauses that can be subsumed resolved using c1.
The collections is populated using the use list of target.
*/
void simplifier::collect_subsumed1_core(clause const & c1, clause_vector & out, literal_vector & out_lits,
void simplifier::collect_subsumed1_core(clause const & c1, clause_vector & out, literal_vector & out_lits,
literal target) {
clause_use_list const & cs = m_use_list.get(target);
clause_use_list::iterator it = cs.mk_iterator();
@ -362,7 +364,7 @@ namespace sat {
CTRACE("resolution_bug", c2.was_removed(), tout << "clause has been removed:\n" << c2 << "\n";);
SASSERT(!c2.was_removed());
if (&c2 != &c1 &&
c1.size() <= c2.size() &&
c1.size() <= c2.size() &&
approx_subset(c1.approx(), c2.approx())) {
m_sub_counter -= c1.size() + c2.size();
literal l;
@ -373,7 +375,7 @@ namespace sat {
}
it.next();
}
}
}
/**
\brief Return the clauses subsumed by c1 and the clauses that can be subsumed resolved using c1.
@ -400,7 +402,7 @@ namespace sat {
if (*l_it == null_literal) {
// c2 was subsumed
if (c1.is_learned() && !c2.is_learned())
c1.unset_learned();
c1.unset_learned();
TRACE("subsumption", tout << c1 << " subsumed " << c2 << "\n";);
remove_clause(c2);
m_num_subsumed++;
@ -447,9 +449,9 @@ namespace sat {
*/
bool simplifier::subsumes0(clause const & c1, clause const & c2) {
unsigned sz2 = c2.size();
for (unsigned i = 0; i < sz2; i++)
for (unsigned i = 0; i < sz2; i++)
mark_visited(c2[i]);
bool r = true;
unsigned sz1 = c1.size();
for (unsigned i = 0; i < sz1; i++) {
@ -459,12 +461,12 @@ namespace sat {
}
}
for (unsigned i = 0; i < sz2; i++)
for (unsigned i = 0; i < sz2; i++)
unmark_visited(c2[i]);
return r;
}
/**
\brief Collect the clauses subsumed by c1 (using the occurrence list of target).
*/
@ -475,7 +477,7 @@ namespace sat {
clause & c2 = it.curr();
SASSERT(!c2.was_removed());
if (&c2 != &c1 &&
c1.size() <= c2.size() &&
c1.size() <= c2.size() &&
approx_subset(c1.approx(), c2.approx())) {
m_sub_counter -= c1.size() + c2.size();
if (subsumes0(c1, c2)) {
@ -485,7 +487,7 @@ namespace sat {
it.next();
}
}
/**
\brief Collect the clauses subsumed by c1
*/
@ -493,8 +495,8 @@ namespace sat {
literal l = get_min_occ_var0(c1);
collect_subsumed0_core(c1, out, l);
}
/**
\brief Perform backward subsumption using c1.
*/
@ -507,16 +509,16 @@ namespace sat {
clause & c2 = *(*it);
// c2 was subsumed
if (c1.is_learned() && !c2.is_learned())
c1.unset_learned();
c1.unset_learned();
TRACE("subsumption", tout << c1 << " subsumed " << c2 << "\n";);
remove_clause(c2);
m_num_subsumed++;
}
}
/**
\brief Eliminate false literals from c, and update occurrence lists
Return true if the clause is satisfied
*/
bool simplifier::cleanup_clause(clause & c, bool in_use_list) {
@ -666,7 +668,7 @@ namespace sat {
back_subsumption1(c);
if (w.is_learned() && !c.is_learned()) {
SASSERT(wlist[j] == w);
TRACE("mark_not_learned_bug",
TRACE("mark_not_learned_bug",
tout << "marking as not learned: " << l2 << " " << wlist[j].is_learned() << "\n";);
wlist[j].mark_not_learned();
mark_as_not_learned_core(get_wlist(~l2), l);
@ -735,7 +737,7 @@ namespace sat {
continue;
}
if (it2->get_literal() == last_lit) {
TRACE("subsumption", tout << "eliminating: " << ~to_literal(l_idx)
TRACE("subsumption", tout << "eliminating: " << ~to_literal(l_idx)
<< " " << it2->get_literal() << "\n";);
elim++;
}
@ -762,12 +764,12 @@ namespace sat {
m_num_sub_res(s.m_num_sub_res) {
m_watch.start();
}
~subsumption_report() {
m_watch.stop();
IF_VERBOSE(SAT_VB_LVL,
IF_VERBOSE(SAT_VB_LVL,
verbose_stream() << " (sat-subsumer :subsumed "
<< (m_simplifier.m_num_subsumed - m_num_subsumed)
<< (m_simplifier.m_num_subsumed - m_num_subsumed)
<< " :subsumption-resolution " << (m_simplifier.m_num_sub_res - m_num_sub_res)
<< " :threshold " << m_simplifier.m_sub_counter
<< mem_stat()
@ -847,12 +849,12 @@ namespace sat {
vector<watch_list> const & m_watches;
public:
literal_lt(use_list const & l, vector<watch_list> const & ws):m_use_list(l), m_watches(ws) {}
unsigned weight(unsigned l_idx) const {
return 2*m_use_list.get(~to_literal(l_idx)).size() + m_watches[l_idx].size();
}
bool operator()(unsigned l_idx1, unsigned l_idx2) const {
bool operator()(unsigned l_idx1, unsigned l_idx2) const {
return weight(l_idx1) < weight(l_idx2);
}
};
@ -861,9 +863,9 @@ namespace sat {
heap<literal_lt> m_queue;
public:
queue(use_list const & l, vector<watch_list> const & ws):m_queue(128, literal_lt(l, ws)) {}
void insert(literal l) {
void insert(literal l) {
unsigned idx = l.index();
m_queue.reserve(idx + 1);
m_queue.reserve(idx + 1);
SASSERT(!m_queue.contains(idx));
m_queue.insert(idx);
}
@ -877,14 +879,14 @@ namespace sat {
literal next() { SASSERT(!empty()); return to_literal(m_queue.erase_min()); }
bool empty() const { return m_queue.empty(); }
};
simplifier & s;
int m_counter;
model_converter & mc;
queue m_queue;
clause_vector m_to_remove;
blocked_clause_elim(simplifier & _s, unsigned limit, model_converter & _mc, use_list & l,
blocked_clause_elim(simplifier & _s, unsigned limit, model_converter & _mc, use_list & l,
vector<watch_list> & wlist):
s(_s),
m_counter(limit),
@ -946,7 +948,7 @@ namespace sat {
clause_vector::iterator it = m_to_remove.begin();
clause_vector::iterator end = m_to_remove.end();
for (; it != end; ++it) {
s.remove_clause(*(*it));
s.remove_clause(*(*it));
}
}
{
@ -1025,12 +1027,12 @@ namespace sat {
m_num_blocked_clauses(s.m_num_blocked_clauses) {
m_watch.start();
}
~blocked_cls_report() {
m_watch.stop();
IF_VERBOSE(SAT_VB_LVL,
IF_VERBOSE(SAT_VB_LVL,
verbose_stream() << " (sat-blocked-clauses :elim-blocked-clauses "
<< (m_simplifier.m_num_blocked_clauses - m_num_blocked_clauses)
<< (m_simplifier.m_num_blocked_clauses - m_num_blocked_clauses)
<< mem_stat()
<< " :time " << std::fixed << std::setprecision(2) << m_watch.get_seconds() << ")\n";);
}
@ -1062,8 +1064,8 @@ namespace sat {
unsigned num_neg = m_use_list.get(neg_l).size();
unsigned num_bin_pos = get_num_non_learned_bin(pos_l);
unsigned num_bin_neg = get_num_non_learned_bin(neg_l);
unsigned cost = 2 * num_pos * num_neg + num_pos * num_bin_neg + num_neg * num_bin_pos;
CTRACE("elim_vars_detail", cost == 0, tout << v << " num_pos: " << num_pos << " num_neg: " << num_neg << " num_bin_pos: " << num_bin_pos
unsigned cost = 2 * num_pos * num_neg + num_pos * num_bin_neg + num_neg * num_bin_pos;
CTRACE("elim_vars_detail", cost == 0, tout << v << " num_pos: " << num_pos << " num_neg: " << num_neg << " num_bin_pos: " << num_bin_pos
<< " num_bin_neg: " << num_bin_neg << " cost: " << cost << "\n";);
return cost;
}
@ -1071,7 +1073,7 @@ namespace sat {
typedef std::pair<bool_var, unsigned> bool_var_and_cost;
struct bool_var_and_cost_lt {
bool operator()(bool_var_and_cost const & p1, bool_var_and_cost const & p2) const { return p1.second < p2.second; }
bool operator()(bool_var_and_cost const & p1, bool_var_and_cost const & p2) const { return p1.second < p2.second; }
};
void simplifier::order_vars_for_elim(bool_var_vector & r) {
@ -1104,7 +1106,7 @@ namespace sat {
r.push_back(it2->first);
}
}
/**
\brief Collect clauses and binary clauses containing l.
*/
@ -1116,7 +1118,7 @@ namespace sat {
SASSERT(r.back().size() == it.curr().size());
it.next();
}
watch_list & wlist = get_wlist(~l);
watch_list::iterator it2 = wlist.begin();
watch_list::iterator end2 = wlist.end();
@ -1129,7 +1131,7 @@ namespace sat {
}
/**
\brief Resolve clauses c1 and c2.
\brief Resolve clauses c1 and c2.
c1 must contain l.
c2 must contain ~l.
Store result in r.
@ -1149,7 +1151,7 @@ namespace sat {
m_visited[l2.index()] = true;
r.push_back(l2);
}
literal not_l = ~l;
sz = c2.size();
m_elim_counter -= sz;
@ -1164,7 +1166,7 @@ namespace sat {
if (!m_visited[l2.index()])
r.push_back(l2);
}
sz = c1.size();
for (unsigned i = 0; i < sz; i++) {
literal l2 = c1[i];
@ -1200,7 +1202,7 @@ namespace sat {
break;
}
}
CTRACE("resolve_bug", it2 == end2,
CTRACE("resolve_bug", it2 == end2,
tout << ~l1 << " -> ";
display(tout, s.m_cls_allocator, wlist1); tout << "\n" << ~l2 << " -> ";
display(tout, s.m_cls_allocator, wlist2); tout << "\n";);
@ -1262,7 +1264,7 @@ namespace sat {
TRACE("resolution_bug", tout << "processing: " << v << "\n";);
if (value(v) != l_undef)
return false;
literal pos_l(v, false);
literal neg_l(v, true);
unsigned num_bin_pos = get_num_non_learned_bin(pos_l);
@ -1274,12 +1276,12 @@ namespace sat {
m_elim_counter -= num_pos + num_neg;
TRACE("resolution", tout << v << " num_pos: " << num_pos << " neg_pos: " << num_neg << "\n";);
if (num_pos >= m_res_occ_cutoff && num_neg >= m_res_occ_cutoff)
return false;
unsigned before_lits = num_bin_pos*2 + num_bin_neg*2;
{
clause_use_list::iterator it = pos_occs.mk_iterator();
while (!it.at_end()) {
@ -1287,7 +1289,7 @@ namespace sat {
it.next();
}
}
{
clause_use_list::iterator it2 = neg_occs.mk_iterator();
while (!it2.at_end()) {
@ -1297,23 +1299,23 @@ namespace sat {
}
TRACE("resolution", tout << v << " num_pos: " << num_pos << " neg_pos: " << num_neg << " before_lits: " << before_lits << "\n";);
if (num_pos >= m_res_occ_cutoff3 && num_neg >= m_res_occ_cutoff3 && before_lits > m_res_lit_cutoff3 && s.m_clauses.size() > m_res_cls_cutoff2)
return false;
if (num_pos >= m_res_occ_cutoff2 && num_neg >= m_res_occ_cutoff2 && before_lits > m_res_lit_cutoff2 &&
if (num_pos >= m_res_occ_cutoff2 && num_neg >= m_res_occ_cutoff2 && before_lits > m_res_lit_cutoff2 &&
s.m_clauses.size() > m_res_cls_cutoff1 && s.m_clauses.size() <= m_res_cls_cutoff2)
return false;
if (num_pos >= m_res_occ_cutoff1 && num_neg >= m_res_occ_cutoff1 && before_lits > m_res_lit_cutoff1 &&
if (num_pos >= m_res_occ_cutoff1 && num_neg >= m_res_occ_cutoff1 && before_lits > m_res_lit_cutoff1 &&
s.m_clauses.size() <= m_res_cls_cutoff1)
return false;
m_pos_cls.reset();
m_neg_cls.reset();
collect_clauses(pos_l, m_pos_cls);
collect_clauses(neg_l, m_neg_cls);
m_elim_counter -= num_pos * num_neg + before_lits;
TRACE("resolution_detail", tout << "collecting number of after_clauses\n";);
unsigned before_clauses = num_pos + num_neg;
unsigned after_clauses = 0;
@ -1350,7 +1352,7 @@ namespace sat {
neg_occs.reset();
m_elim_counter -= num_pos * num_neg + before_lits;
it1 = m_pos_cls.begin();
end1 = m_pos_cls.end();
for (; it1 != end1; ++it1) {
@ -1393,7 +1395,7 @@ namespace sat {
return true;
}
}
return true;
}
@ -1406,10 +1408,10 @@ namespace sat {
m_num_elim_vars(s.m_num_elim_vars) {
m_watch.start();
}
~elim_var_report() {
m_watch.stop();
IF_VERBOSE(SAT_VB_LVL,
IF_VERBOSE(SAT_VB_LVL,
verbose_stream() << " (sat-resolution :elim-bool-vars "
<< (m_simplifier.m_num_elim_vars - m_num_elim_vars)
<< " :threshold " << m_simplifier.m_elim_counter
@ -1417,12 +1419,12 @@ namespace sat {
<< " :time " << std::fixed << std::setprecision(2) << m_watch.get_seconds() << ")\n";);
}
};
void simplifier::elim_vars() {
elim_var_report rpt(*this);
bool_var_vector vars;
order_vars_for_elim(vars);
bool_var_vector::iterator it = vars.begin();
bool_var_vector::iterator end = vars.end();
for (; it != end; ++it) {
@ -1463,7 +1465,7 @@ namespace sat {
void simplifier::collect_param_descrs(param_descrs & r) {
sat_simplifier_params::collect_param_descrs(r);
}
void simplifier::collect_statistics(statistics & st) {
st.update("subsumed", m_num_subsumed);
st.update("subsumption resolution", m_num_sub_res);
@ -1471,7 +1473,7 @@ namespace sat {
st.update("elim bool vars", m_num_elim_vars);
st.update("elim blocked clauses", m_num_blocked_clauses);
}
void simplifier::reset_statistics() {
m_num_blocked_clauses = 0;
m_num_subsumed = 0;