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parallelizing ccc

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2017-04-23 23:10:23 -07:00
parent d052155f6e
commit 3aaea6b920
3 changed files with 73 additions and 41 deletions
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24
src/sat/sat_ccc.cpp
View file

@ -35,7 +35,7 @@ using namespace sat;
std::ostream& ccc::decision::pp(std::ostream& out) const { std::ostream& ccc::decision::pp(std::ostream& out) const {
out << "(" out << "("
<< " id:" << m_id << "id:" << m_id
<< " l:" << m_literal << " l:" << m_literal
<< " d:" << m_depth; << " d:" << m_depth;
if (m_spawn_id != 0) { if (m_spawn_id != 0) {
@ -187,9 +187,9 @@ void ccc::replay_decisions(solver& s, svector<decision>& decisions, unsigned thr
s.propagate(true); s.propagate(true);
for (unsigned i = s.scope_lvl(); !s.inconsistent() && i < decisions.size(); ++i) { for (unsigned i = s.scope_lvl(); !s.inconsistent() && i < decisions.size(); ++i) {
decision const& d = decisions[i]; decision const& d = decisions[i];
IF_VERBOSE(2, verbose_stream() << "replay " << d.get_literal(thread_id) << " " << s.value(d.get_literal(thread_id)) << "\n";); IF_VERBOSE(2, verbose_stream() << thread_id << ": replay " << d.get_literal(thread_id) << " " << s.value(d.get_literal(thread_id)) << "\n";);
if (!push_decision(s, d, thread_id)) { if (!push_decision(s, decisions, d, thread_id)) {
// negation of decision is implied. // negation of decision is implied.
// check_non_model("replay", decisions); // check_non_model("replay", decisions);
decisions.resize(i); decisions.resize(i);
@ -214,7 +214,7 @@ bool ccc::get_solved(svector<decision>& decisions) {
if (branch_id == d.m_id) { if (branch_id == d.m_id) {
if (d.m_spawn_id == thread_id) { if (d.m_spawn_id == thread_id) {
SASSERT(d.m_spawn_id > 0); SASSERT(d.m_spawn_id > 0);
free_conquer(thread_id); free_conquer(thread_id);
IF_VERBOSE(1, verbose_stream() << "close " << i << "\n";); IF_VERBOSE(1, verbose_stream() << "close " << i << "\n";);
d.close(); d.close();
} }
@ -258,10 +258,18 @@ bool ccc::get_decision(unsigned thread_id, decision& d) {
return result; return result;
} }
bool ccc::push_decision(solver& s, decision const& d, unsigned thread_id) { bool ccc::push_decision(solver& s, svector<decision> const& decisions, decision const& d, unsigned thread_id) {
literal lit = d.get_literal(thread_id); literal lit = d.get_literal(thread_id);
switch (s.value(lit)) { switch (s.value(lit)) {
case l_false: case l_false:
// TBD: we leak conquer threads if they backjump below spawn point.
if (decisions.empty() && decisions.back().m_spawn_id == thread_id && decisions.back().m_id != d.m_id) {
IF_VERBOSE(0, verbose_stream() << "LEAK avoided\n";);
#pragma omp critical (ccc_solved)
{
m_solved.push(solution(thread_id, decisions.back().m_id));
}
}
#pragma omp critical (ccc_solved) #pragma omp critical (ccc_solved)
{ {
m_solved.push(solution(thread_id, d.m_id)); m_solved.push(solution(thread_id, d.m_id));
@ -311,11 +319,11 @@ bool ccc::cube_decision(solver& s, svector<decision>& decisions, unsigned thread
SASSERT(s.m_qhead == s.m_trail.size()); SASSERT(s.m_qhead == s.m_trail.size());
SASSERT(s.scope_lvl() == decisions.size()); SASSERT(s.scope_lvl() == decisions.size());
literal lit = d.get_literal(thread_id); literal lit = d.get_literal(thread_id);
IF_VERBOSE(1, verbose_stream() << "cube " << decisions.size() << " " << d.get_literal(thread_id) << "\n";); IF_VERBOSE(1, verbose_stream() << thread_id << ": cube " << decisions.size() << " " << d.get_literal(thread_id) << "\n";);
IF_VERBOSE(2, pp(verbose_stream() << "push ", decisions) << " @ " << s.scope_lvl() << " " << s.value(lit) << "\n"; IF_VERBOSE(2, pp(verbose_stream() << thread_id << ": push ", decisions) << " @ " << s.scope_lvl() << " " << s.value(lit) << "\n";
if (s.value(lit) == l_false) verbose_stream() << "level: " << s.lvl(lit) << "\n";); if (s.value(lit) == l_false) verbose_stream() << "level: " << s.lvl(lit) << "\n";);
if (push_decision(s, d, thread_id)) { if (push_decision(s, decisions, d, thread_id)) {
decisions.push_back(d); decisions.push_back(d);
} }

2
src/sat/sat_ccc.h
View file

@ -67,7 +67,7 @@ namespace sat {
bool cube_decision(solver& s, svector<decision>& decisions, unsigned thread_id); bool cube_decision(solver& s, svector<decision>& decisions, unsigned thread_id);
lbool bounded_search(solver& s, svector<decision>& decisions, unsigned thread_id); lbool bounded_search(solver& s, svector<decision>& decisions, unsigned thread_id);
bool push_decision(solver& s, decision const& d, unsigned thread_id); bool push_decision(solver& s, svector<decision> const& decisions, decision const& d, unsigned thread_id);
lbool cube(); lbool cube();
lbool cube(svector<decision>& decisions, lookahead& lh); lbool cube(svector<decision>& decisions, lookahead& lh);
void put_decision(decision const& d); void put_decision(decision const& d);

88
src/sat/sat_lookahead.h
View file

@ -59,7 +59,9 @@ namespace sat {
} }
class lookahead { class lookahead {
solver& s; solver& m_s;
unsigned m_num_vars;
reslimit m_rlimit;
friend class ccc; friend class ccc;
@ -243,14 +245,20 @@ namespace sat {
m_binary[(~l2).index()].push_back(l1); m_binary[(~l2).index()].push_back(l1);
m_binary_trail.push_back((~l1).index()); m_binary_trail.push_back((~l1).index());
++m_stats.m_add_binary; ++m_stats.m_add_binary;
if (s.m_config.m_drat) validate_binary(l1, l2); if (m_s.m_config.m_drat) validate_binary(l1, l2);
} }
void del_binary(unsigned idx) { void del_binary(unsigned idx) {
// TRACE("sat", display(tout << "Delete " << to_literal(idx) << "\n");); // TRACE("sat", display(tout << "Delete " << to_literal(idx) << "\n"););
literal_vector & lits = m_binary[idx]; literal_vector & lits = m_binary[idx];
literal l = lits.back(); if (lits.empty()) IF_VERBOSE(0, verbose_stream() << "empty literals\n";);
literal l = lits.back();
lits.pop_back(); lits.pop_back();
if (m_binary[(~l).index()].back() != ~to_literal(idx)) {
IF_VERBOSE(0, verbose_stream() << "pop bad literal: " << idx << " " << (~l).index() << "\n";);
}
if (m_binary[(~l).index()].empty())
IF_VERBOSE(0, verbose_stream() << "empty binary\n";);
m_binary[(~l).index()].pop_back(); m_binary[(~l).index()].pop_back();
++m_stats.m_del_binary; ++m_stats.m_del_binary;
} }
@ -547,7 +555,7 @@ namespace sat {
void ensure_H(unsigned level) { void ensure_H(unsigned level) {
while (m_H.size() <= level) { while (m_H.size() <= level) {
m_H.push_back(svector<float>()); m_H.push_back(svector<float>());
m_H.back().resize(s.num_vars() * 2, 0); m_H.back().resize(m_num_vars * 2, 0);
} }
} }
@ -574,6 +582,9 @@ namespace sat {
float sum = 0, tsum = 0; float sum = 0, tsum = 0;
literal_vector::iterator it = m_binary[l.index()].begin(), end = m_binary[l.index()].end(); literal_vector::iterator it = m_binary[l.index()].begin(), end = m_binary[l.index()].end();
for (; it != end; ++it) { for (; it != end; ++it) {
bool_var v = it->var();
if (it->index() >= h.size())
IF_VERBOSE(0, verbose_stream() << l << " " << *it << " " << h.size() << "\n";);
if (is_undef(*it)) sum += h[it->index()]; if (is_undef(*it)) sum += h[it->index()];
// if (m_freevars.contains(it->var())) sum += h[it->index()]; // if (m_freevars.contains(it->var())) sum += h[it->index()];
} }
@ -593,7 +604,7 @@ namespace sat {
} }
case watched::CLAUSE: { case watched::CLAUSE: {
clause_offset cls_off = wit->get_clause_offset(); clause_offset cls_off = wit->get_clause_offset();
clause & c = *(s.m_cls_allocator.get_clause(cls_off)); clause & c = *(m_cls_allocator.get_clause(cls_off));
// approximation compared to ternary clause case: // approximation compared to ternary clause case:
// we pick two other literals from the clause. // we pick two other literals from the clause.
if (c[0] == ~l) { if (c[0] == ~l) {
@ -1026,26 +1037,26 @@ namespace sat {
m_lits.push_back(lit_info()); m_lits.push_back(lit_info());
m_rating.push_back(0); m_rating.push_back(0);
m_vprefix.push_back(prefix()); m_vprefix.push_back(prefix());
if (!s.was_eliminated(v)) if (!m_s.was_eliminated(v))
m_freevars.insert(v); m_freevars.insert(v);
} }
void init() { void init() {
m_delta_trigger = s.num_vars()/10; m_delta_trigger = m_num_vars/10;
m_config.m_dl_success = 0.8; m_config.m_dl_success = 0.8;
m_inconsistent = false; m_inconsistent = false;
m_qhead = 0; m_qhead = 0;
m_bstamp_id = 0; m_bstamp_id = 0;
for (unsigned i = 0; i < s.num_vars(); ++i) { for (unsigned i = 0; i < m_num_vars; ++i) {
init_var(i); init_var(i);
} }
// copy binary clauses // copy binary clauses
unsigned sz = s.m_watches.size(); unsigned sz = m_s.m_watches.size();
for (unsigned l_idx = 0; l_idx < sz; ++l_idx) { for (unsigned l_idx = 0; l_idx < sz; ++l_idx) {
literal l = ~to_literal(l_idx); literal l = ~to_literal(l_idx);
watch_list const & wlist = s.m_watches[l_idx]; watch_list const & wlist = m_s.m_watches[l_idx];
watch_list::const_iterator it = wlist.begin(); watch_list::const_iterator it = wlist.begin();
watch_list::const_iterator end = wlist.end(); watch_list::const_iterator end = wlist.end();
for (; it != end; ++it) { for (; it != end; ++it) {
@ -1057,21 +1068,21 @@ namespace sat {
} }
} }
copy_clauses(s.m_clauses); copy_clauses(m_s.m_clauses);
copy_clauses(s.m_learned); copy_clauses(m_s.m_learned);
// copy units // copy units
unsigned trail_sz = s.init_trail_size(); unsigned trail_sz = m_s.init_trail_size();
for (unsigned i = 0; i < trail_sz; ++i) { for (unsigned i = 0; i < trail_sz; ++i) {
literal l = s.m_trail[i]; literal l = m_s.m_trail[i];
if (!s.was_eliminated(l.var())) { if (!m_s.was_eliminated(l.var())) {
if (s.m_config.m_drat) m_drat.add(l, false); if (m_s.m_config.m_drat) m_drat.add(l, false);
assign(l); assign(l);
} }
} }
propagate(); propagate();
m_qhead = m_trail.size(); m_qhead = m_trail.size();
TRACE("sat", s.display(tout); display(tout);); TRACE("sat", m_s.display(tout); display(tout););
} }
void copy_clauses(clause_vector const& clauses) { void copy_clauses(clause_vector const& clauses) {
@ -1087,7 +1098,7 @@ namespace sat {
for (unsigned i = 0; i < c.size(); ++i) { for (unsigned i = 0; i < c.size(); ++i) {
m_full_watches[(~c[i]).index()].push_back(c1); m_full_watches[(~c[i]).index()].push_back(c1);
} }
if (s.m_config.m_drat) m_drat.add(c, false); if (m_s.m_config.m_drat) m_drat.add(c, false);
} }
} }
@ -1207,7 +1218,7 @@ namespace sat {
clause const& get_clause(watch_list::iterator it) const { clause const& get_clause(watch_list::iterator it) const {
clause_offset cls_off = it->get_clause_offset(); clause_offset cls_off = it->get_clause_offset();
return *(s.m_cls_allocator.get_clause(cls_off)); return *(m_cls_allocator.get_clause(cls_off));
} }
bool is_nary_propagation(clause const& c, literal l) const { bool is_nary_propagation(clause const& c, literal l) const {
@ -1288,7 +1299,7 @@ namespace sat {
break; break;
} }
clause_offset cls_off = it->get_clause_offset(); clause_offset cls_off = it->get_clause_offset();
clause & c = *(s.m_cls_allocator.get_clause(cls_off)); clause & c = *(m_cls_allocator.get_clause(cls_off));
if (c[0] == ~l) if (c[0] == ~l)
std::swap(c[0], c[1]); std::swap(c[0], c[1]);
if (is_true(c[0])) { if (is_true(c[0])) {
@ -1426,7 +1437,7 @@ namespace sat {
while (change && !inconsistent()) { while (change && !inconsistent()) {
change = false; change = false;
for (unsigned i = 0; !inconsistent() && i < m_lookahead.size(); ++i) { for (unsigned i = 0; !inconsistent() && i < m_lookahead.size(); ++i) {
s.checkpoint(); checkpoint();
literal lit = m_lookahead[i].m_lit; literal lit = m_lookahead[i].m_lit;
if (is_fixed_at(lit, c_fixed_truth)) continue; if (is_fixed_at(lit, c_fixed_truth)) continue;
unsigned level = base + m_lookahead[i].m_offset; unsigned level = base + m_lookahead[i].m_offset;
@ -1501,7 +1512,7 @@ namespace sat {
float mixd = mix_diff(diff1, diff2); float mixd = mix_diff(diff1, diff2);
if (mixd == h) ++count; if (mixd == h) ++count;
if (mixd > h || (mixd == h && s.m_rand(count) == 0)) { if (mixd > h || (mixd == h && m_s.m_rand(count) == 0)) {
CTRACE("sat", l != null_literal, tout << lit << " mix diff: " << mixd << "\n";); CTRACE("sat", l != null_literal, tout << lit << " mix diff: " << mixd << "\n";);
if (mixd > h) count = 1; if (mixd > h) count = 1;
h = mixd; h = mixd;
@ -1666,7 +1677,7 @@ namespace sat {
unsigned scope_lvl() const { return m_trail_lim.size(); } unsigned scope_lvl() const { return m_trail_lim.size(); }
void validate_assign(literal l) { void validate_assign(literal l) {
if (s.m_config.m_drat && m_search_mode == lookahead_mode::searching) { if (m_s.m_config.m_drat && m_search_mode == lookahead_mode::searching) {
m_assumptions.push_back(l); m_assumptions.push_back(l);
m_drat.add(m_assumptions); m_drat.add(m_assumptions);
m_assumptions.pop_back(); m_assumptions.pop_back();
@ -1727,7 +1738,7 @@ namespace sat {
while (true) { while (true) {
TRACE("sat", display(tout);); TRACE("sat", display(tout););
inc_istamp(); inc_istamp();
s.checkpoint(); checkpoint();
if (inconsistent()) { if (inconsistent()) {
if (!backtrack(trail)) return l_false; if (!backtrack(trail)) return l_false;
continue; continue;
@ -1751,7 +1762,7 @@ namespace sat {
void init_model() { void init_model() {
m_model.reset(); m_model.reset();
for (unsigned i = 0; i < s.num_vars(); ++i) { for (unsigned i = 0; i < m_num_vars; ++i) {
lbool val; lbool val;
literal lit(i, false); literal lit(i, false);
if (is_undef(lit)) { if (is_undef(lit)) {
@ -1810,17 +1821,30 @@ namespace sat {
init(); init();
} }
void checkpoint() {
if (!m_rlimit.inc()) {
throw solver_exception(Z3_CANCELED_MSG);
}
if (memory::get_allocation_size() > m_s.m_config.m_max_memory) {
throw solver_exception(Z3_MAX_MEMORY_MSG);
}
}
public: public:
lookahead(solver& s) : lookahead(solver& s) :
s(s), m_s(s),
m_num_vars(s.num_vars()),
m_drat(s), m_drat(s),
m_num_tc1(0), m_num_tc1(0),
m_level(2), m_level(2),
m_prefix(0) { m_prefix(0) {
m_s.rlimit().push_child(&m_rlimit);
} }
~lookahead() { ~lookahead() {
del_clauses(); del_clauses();
m_s.rlimit().pop_child();
} }
lbool check() { lbool check() {
@ -1842,14 +1866,14 @@ namespace sat {
unsigned num_units = 0; unsigned num_units = 0;
for (unsigned i = 0; i < m_trail.size(); ++i) { for (unsigned i = 0; i < m_trail.size(); ++i) {
literal lit = m_trail[i]; literal lit = m_trail[i];
if (s.value(lit) == l_undef && !s.was_eliminated(lit.var())) { if (m_s.value(lit) == l_undef && !m_s.was_eliminated(lit.var())) {
s.m_simplifier.propagate_unit(lit); m_s.m_simplifier.propagate_unit(lit);
++num_units; ++num_units;
} }
} }
IF_VERBOSE(1, verbose_stream() << "units found: " << num_units << "\n";); IF_VERBOSE(1, verbose_stream() << "units found: " << num_units << "\n";);
s.m_simplifier.subsume(); m_s.m_simplifier.subsume();
m_lookahead.reset(); m_lookahead.reset();
} }
@ -1868,20 +1892,20 @@ namespace sat {
if (inconsistent()) return; if (inconsistent()) return;
literal_vector roots; literal_vector roots;
bool_var_vector to_elim; bool_var_vector to_elim;
for (unsigned i = 0; i < s.num_vars(); ++i) { for (unsigned i = 0; i < m_num_vars; ++i) {
roots.push_back(literal(i, false)); roots.push_back(literal(i, false));
} }
for (unsigned i = 0; i < m_candidates.size(); ++i) { for (unsigned i = 0; i < m_candidates.size(); ++i) {
bool_var v = m_candidates[i].m_var; bool_var v = m_candidates[i].m_var;
literal lit = literal(v, false); literal lit = literal(v, false);
literal p = get_parent(lit); literal p = get_parent(lit);
if (p != null_literal && p.var() != v && !s.is_external(v) && !s.was_eliminated(v) && !s.was_eliminated(p.var())) { if (p != null_literal && p.var() != v && !m_s.is_external(v) && !m_s.was_eliminated(v) && !m_s.was_eliminated(p.var())) {
to_elim.push_back(v); to_elim.push_back(v);
roots[v] = p; roots[v] = p;
} }
} }
IF_VERBOSE(1, verbose_stream() << "eliminate " << to_elim.size() << " variables\n";); IF_VERBOSE(1, verbose_stream() << "eliminate " << to_elim.size() << " variables\n";);
elim_eqs elim(s); elim_eqs elim(m_s);
elim(roots, to_elim); elim(roots, to_elim);
} }
m_lookahead.reset(); m_lookahead.reset();