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parallelizing lh

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2017-04-26 00:22:59 -07:00
parent c637240c40
commit 4575b2820d
2 changed files with 128 additions and 105 deletions
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198
src/sat/sat_ccc.cpp
View file

@ -33,53 +33,36 @@ Notes:
using namespace sat; using namespace sat;
std::ostream& ccc::decision::pp(std::ostream& out) const { // ------------
out << "(" // cuber
<< "id:" << m_id
<< " l:" << m_literal
<< " d:" << m_depth;
if (m_spawn_id != 0) {
out << " s:" << m_spawn_id;
}
out << ") ";
return out;
}
std::ostream& ccc::pp(std::ostream& out, svector<decision> const& v) { ccc::cuber::cuber(ccc& c): m_ccc(c), lh(c.m_s), m_branch_id(0) {}
for (unsigned i = 0; i < v.size(); ++i) {
v[i].pp(out);
}
return out;
}
lbool ccc::cube() { lbool ccc::cuber::search() {
m_branch_id = 0; m_branch_id = 0;
m_last_closure_level = 1000; m_last_closure_level = 1000;
lookahead lh(m_s);
lh.init_search(); lh.init_search();
lh.m_model.reset(); lh.m_model.reset();
lookahead::scoped_level _sl(lh, lh.c_fixed_truth); lookahead::scoped_level _sl(lh, lh.c_fixed_truth);
literal_vector trail;
svector<decision> decisions;
lh.m_search_mode = lookahead_mode::searching; lh.m_search_mode = lookahead_mode::searching;
lbool r = cube(decisions, lh); lbool r = research();
if (r == l_true) { if (r == l_true) {
m_model = lh.get_model(); m_ccc.m_model = lh.get_model();
} }
lh.collect_statistics(m_lh_stats); lh.collect_statistics(m_ccc.m_lh_stats);
return r; return r;
} }
lbool ccc::cube(svector<decision>& decisions, lookahead& lh) { lbool ccc::cuber::research() {
m_s.checkpoint(); m_ccc.m_s.checkpoint();
if (lh.inconsistent()) { if (lh.inconsistent()) {
return l_false; return l_false;
} }
if (get_solved(decisions)) { if (get_solved()) {
return l_false; return l_false;
} }
@ -94,41 +77,47 @@ lbool ccc::cube(svector<decision>& decisions, lookahead& lh) {
} }
if (!decisions.empty()) { if (!decisions.empty()) {
put_decision(decisions.back()); m_ccc.put_decision(decisions.back());
} }
// update trail and decisions // update trail and decisions
++lh.m_stats.m_decisions; ++lh.m_stats.m_decisions;
unsigned parent_id = decisions.empty() ? 0 : decisions.back().m_id; unsigned parent_id = decisions.empty() ? 0 : decisions.back().m_id;
unsigned spawn_id = spawn_conquer(decisions); unsigned spawn_id = spawn_conquer();
unsigned branch1 = m_branch_id++; unsigned branch1 = m_branch_id++;
unsigned branch2 = m_branch_id++; unsigned branch2 = m_branch_id++;
decision d(branch1, decisions.size() + 1, l, parent_id, spawn_id); decision d(branch1, decisions.size() + 1, l, parent_id, spawn_id);
decisions.push_back(d); decisions.push_back(d);
IF_VERBOSE(1, d.pp(verbose_stream() << "select " << m_last_closure_level << " ") << "\n";);
IF_VERBOSE(1, verbose_stream() << "select " << pp_prefix(lh.m_prefix, lh.m_trail_lim.size()) << ": " << l << " " << lh.m_trail.size() << "\n";); IF_VERBOSE(1, verbose_stream() << "select " << pp_prefix(lh.m_prefix, lh.m_trail_lim.size()) << ": " << l << " " << lh.m_trail.size() << "\n";);
IF_VERBOSE(2, pp(verbose_stream(), decisions) << "\n"; ); IF_VERBOSE(2, pp(verbose_stream(), decisions) << "\n"; );
TRACE("sat", tout << "choose: " << l << "\n";); TRACE("sat", tout << "choose: " << l << "\n";);
lh.push(l, lh.c_fixed_truth); lh.push(l, lh.c_fixed_truth);
lbool r = cube(decisions, lh); lbool r = research();
if (r == l_false) { if (r == l_false) {
lh.pop(); lh.pop();
if (decisions.back().is_closed()) { if (decisions.back().is_closed()) {
// branch was solved by a spawned conquer process // branch was solved by a spawned conquer process
IF_VERBOSE(0, verbose_stream() << "closed " << decisions.back().m_id << "\n";); IF_VERBOSE(1, decisions.back().pp(verbose_stream() << "closed ") << "\n";);
r = l_false; r = l_false;
decisions.pop_back(); decisions.pop_back();
} }
else { else {
if (spawn_id > 0) {
free_conquer(spawn_id);
m_last_closure_level *= 3;
m_last_closure_level /= 4;
}
lh.inc_istamp(); lh.inc_istamp();
lh.flip_prefix(); lh.flip_prefix();
lh.push(~l, lh.c_fixed_truth); lh.push(~l, lh.c_fixed_truth);
decisions.back().negate(); decisions.back().negate();
decisions.back().m_id = branch2; decisions.back().m_id = branch2;
decisions.back().m_spawn_id = 0; decisions.back().m_spawn_id = 0;
r = cube(decisions, lh); r = research();
if (r == l_false) { if (r == l_false) {
lh.pop(); lh.pop();
decisions.pop_back(); decisions.pop_back();
@ -138,45 +127,50 @@ lbool ccc::cube(svector<decision>& decisions, lookahead& lh) {
return r; return r;
} }
void ccc::update_closure_level(decision const& d, int offset) { void ccc::cuber::update_closure_level(decision const& d, int offset) {
m_last_closure_level = (d.m_depth + 3*m_last_closure_level) / 4 + offset; m_last_closure_level = (d.m_depth + 3*m_last_closure_level) / 4;
if (m_last_closure_level >= static_cast<unsigned>(abs(offset))) {
m_last_closure_level += offset;
}
} }
unsigned ccc::cuber::spawn_conquer() {
unsigned ccc::spawn_conquer(svector<decision> const& decisions) {
unsigned result = 0; unsigned result = 0;
// //
// decisions must have been solved at a higher level by a conquer thread // decisions must have been solved at a higher level by a conquer thread
// //
if (m_ccc_stats.m_cdcl_closed < 10) { if (!m_free_threads.empty()) {
return 0; if (m_last_closure_level <= decisions.size()) {
} result = m_free_threads.back();
if (!m_free_threads.empty() && m_last_closure_level >= decisions.size()) { ++m_ccc.m_ccc_stats.m_spawn_opened;
result = m_free_threads.back(); m_free_threads.pop_back();
m_free_threads.pop_back(); }
IF_VERBOSE(0, verbose_stream() << "spawn " << result << " with " << decisions.size() << " decisions\n";); else {
IF_VERBOSE(1, verbose_stream() << m_last_closure_level << " " << decisions.size() << "\n";);
}
} }
return result; return result;
} }
void ccc::free_conquer(unsigned thread_id) {
if (thread_id != 0) { void ccc::cuber::free_conquer(unsigned id) {
IF_VERBOSE(0, verbose_stream() << "free conquer " << thread_id << "\n";); if (id != 0) {
m_free_threads.push_back(thread_id); m_free_threads.push_back(id);
} }
} }
bool ccc::get_solved(svector<decision>& decisions) {
bool ccc::cuber::get_solved() {
// check if CDCL solver got ahead. // check if CDCL solver got ahead.
bool do_pop = false; bool do_pop = false;
solution sol;
while (true) { while (true) {
solution sol;
bool is_empty = true; bool is_empty = true;
#pragma omp critical (ccc_solved) #pragma omp critical (ccc_solved)
{ {
if (do_pop) m_solved.pop_front(); if (do_pop) m_ccc.m_solved.pop_front();
if (!m_solved.empty()) { if (!m_ccc.m_solved.empty()) {
sol = m_solved.top(); sol = m_ccc.m_solved.top();
is_empty = false; is_empty = false;
} }
} }
@ -186,30 +180,31 @@ bool ccc::get_solved(svector<decision>& decisions) {
do_pop = true; do_pop = true;
unsigned branch_id = sol.m_branch_id; unsigned branch_id = sol.m_branch_id;
unsigned thread_id = sol.m_thread_id; unsigned thread_id = sol.m_thread_id;
free_conquer(thread_id); bool found = false;
for (unsigned i = decisions.size(); i > 0; ) { for (unsigned i = decisions.size(); i > 0; ) {
--i; --i;
decision& d = decisions[i]; decision& d = decisions[i];
if (branch_id == d.m_id) { if (branch_id == d.m_id) {
if (d.m_spawn_id == thread_id && thread_id != 0) { if (d.m_spawn_id == thread_id && thread_id != 0) {
SASSERT(d.m_spawn_id > 0); SASSERT(d.m_spawn_id > 0);
IF_VERBOSE(0, verbose_stream() << thread_id << ": spawn close " << branch_id << " " << " " << d.m_depth << "\n";); IF_VERBOSE(1, d.pp(verbose_stream() << thread_id << ": spawn close ") << "\n";);
++m_ccc_stats.m_spawn_closed; ++m_ccc.m_ccc_stats.m_spawn_closed;
d.close(); d.close();
free_conquer(thread_id);
update_closure_level(d, -1); update_closure_level(d, -1);
break; break;
} }
else { else {
IF_VERBOSE(0, verbose_stream() << thread_id << ": conquer " << branch_id << " " << d.m_depth << " " << decisions.size() << " " << d.get_literal(thread_id) << "\n";); IF_VERBOSE(1, d.pp(verbose_stream() << thread_id << ": conquer ") << "\n";);
++m_ccc_stats.m_cdcl_closed; ++m_ccc.m_ccc_stats.m_cdcl_closed;
update_closure_level(d, 1); update_closure_level(d, 1);
return true; return true;
} }
} }
// branch is even, d has moved to the next branch // branch is even, d has moved to the next branch
if (branch_id == (d.m_id & ~0x1) && d.m_spawn_id == thread_id && thread_id != 0) { if (branch_id == (d.m_id & ~0x1) && d.m_spawn_id == thread_id && thread_id != 0) {
IF_VERBOSE(0, verbose_stream() << thread_id << ": spawn conquer " << branch_id << " " << " " << d.m_depth << "\n";); IF_VERBOSE(1, d.pp(verbose_stream() << thread_id << ": spawn conquer ") << "\n";);
++m_ccc_stats.m_cdcl_closed; ++m_ccc.m_ccc_stats.m_cdcl_closed;
update_closure_level(d, 1); update_closure_level(d, 1);
return true; return true;
} }
@ -217,22 +212,6 @@ bool ccc::get_solved(svector<decision>& decisions) {
} }
} }
void ccc::put_decision(decision const& d) {
for (unsigned i = 0; i < m_num_conquer; ++i) {
#pragma omp critical (ccc_decisions)
{
while (!m_decisions[i].empty()) {
decision d = m_decisions[i].back();
if (d.m_depth < d.m_depth || d.m_spawn_id != 0) {
break;
}
m_decisions[i].pop_back();
}
m_decisions[i].push(d);
}
}
}
// --------------------- // ---------------------
// conquer state machine // conquer state machine
@ -272,7 +251,7 @@ void ccc::conquer::replay_decisions() {
if (!push_decision(d)) { if (!push_decision(d)) {
// negation of decision is implied. // negation of decision is implied.
IF_VERBOSE(0, verbose_stream() << thread_id << ": backjump to level " << i << " of " << decisions.size() << "\n";); IF_VERBOSE(1, d.pp(verbose_stream() << thread_id << ": backjump to level " << i << " ") << "\n";);
while (decisions.size() > i) { while (decisions.size() > i) {
pop_decision(decisions.back()); pop_decision(decisions.back());
decisions.pop_back(); decisions.pop_back();
@ -282,7 +261,7 @@ void ccc::conquer::replay_decisions() {
if (d.m_spawn_id == thread_id && d.is_left()) { if (d.m_spawn_id == thread_id && d.is_left()) {
// we pushed the right branch on this thread. // we pushed the right branch on this thread.
IF_VERBOSE(0, verbose_stream() << thread_id << ": skip left branch on level " << i + 1 << " of " << decisions.size() << "\n";); IF_VERBOSE(1, d.pp(verbose_stream() << thread_id << ": skip left branch on level " << i + 1 << " ") << "\n";);
break; break;
} }
} }
@ -293,11 +272,11 @@ void ccc::conquer::pop_decision(decision const& d) {
if (d.is_spawned(thread_id)) { if (d.is_spawned(thread_id)) {
tid = thread_id; tid = thread_id;
m_spawned = false; m_spawned = false;
IF_VERBOSE(0, verbose_stream() << thread_id << " retire spawn\n";); IF_VERBOSE(1, d.pp(verbose_stream() << thread_id << ": retire spawn ") << "\n";);
} }
#pragma omp critical (ccc_solved) #pragma omp critical (ccc_solved)
{ {
super.m_solved.push(solution(tid, d.m_id)); m_ccc.m_solved.push(solution(tid, d.m_id));
} }
} }
@ -328,11 +307,11 @@ bool ccc::conquer::cube_decision() {
SASSERT(s.m_qhead == s.m_trail.size()); SASSERT(s.m_qhead == s.m_trail.size());
while (true) { while (true) {
if (!super.get_decision(thread_id, d)) { if (!m_ccc.get_decision(thread_id, d)) {
return false; return false;
} }
if (d.is_spawned(thread_id)) IF_VERBOSE(0, verbose_stream() << thread_id << ": spawned d:" << d.m_depth << " decisions: " << decisions.size() << "\n";); if (d.is_spawned(thread_id)) IF_VERBOSE(1, d.pp(verbose_stream() << thread_id << " ") << "\n";);
if (!decisions.empty() && decisions.back().m_depth + 1 < d.m_depth) { if (!decisions.empty() && decisions.back().m_depth + 1 < d.m_depth) {
if (d.is_spawned(thread_id)) { if (d.is_spawned(thread_id)) {
@ -349,8 +328,7 @@ bool ccc::conquer::cube_decision() {
SASSERT(d.m_spawn_id == 0); SASSERT(d.m_spawn_id == 0);
SASSERT(decisions.back().is_left()); SASSERT(decisions.back().is_left());
SASSERT(!d.is_left()); SASSERT(!d.is_left());
IF_VERBOSE(0, verbose_stream() << thread_id << " inherit spawn\n";); IF_VERBOSE(1, verbose_stream() << thread_id << " inherit spawn\n";);
d.m_spawn_id = thread_id;
decisions.back().m_spawn_id = 0; decisions.back().m_spawn_id = 0;
m_spawned = false; m_spawned = false;
} }
@ -375,7 +353,7 @@ bool ccc::conquer::cube_decision() {
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(0, verbose_stream() << thread_id << ": cube " << decisions.size() << " " << d.get_literal(thread_id) << "\n";); IF_VERBOSE(1, d.pp(verbose_stream() << thread_id << ": cube ") << "\n";);
IF_VERBOSE(2, pp(verbose_stream() << thread_id << ": 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";);
@ -410,6 +388,27 @@ lbool ccc::conquer::bounded_search() {
} }
} }
// --------------
// shared state
std::ostream& ccc::decision::pp(std::ostream& out) const {
out << "("
<< "id:" << m_id
<< " l:" << m_literal
<< " d:" << m_depth;
if (m_spawn_id != 0) {
out << " s:" << m_spawn_id;
}
out << ") ";
return out;
}
std::ostream& ccc::pp(std::ostream& out, svector<decision> const& v) {
for (unsigned i = 0; i < v.size(); ++i) {
v[i].pp(out);
}
return out;
}
bool ccc::get_decision(unsigned thread_id, decision& d) { bool ccc::get_decision(unsigned thread_id, decision& d) {
SASSERT(0 < thread_id && thread_id <= m_decisions.size()); SASSERT(0 < thread_id && thread_id <= m_decisions.size());
@ -424,6 +423,21 @@ bool ccc::get_decision(unsigned thread_id, decision& d) {
return result; return result;
} }
void ccc::put_decision(decision const& d) {
for (unsigned i = 0; i < m_num_conquer; ++i) {
#pragma omp critical (ccc_decisions)
{
while (false && !m_decisions[i].empty()) { // introduces contention.
decision d = m_decisions[i].back();
if (d.m_depth < d.m_depth || d.m_spawn_id != 0) {
break;
}
m_decisions[i].pop_back();
}
m_decisions[i].push(d);
}
}
}
lbool ccc::search() { lbool ccc::search() {
enum par_exception_kind { enum par_exception_kind {
@ -436,7 +450,6 @@ lbool ccc::search() {
m_cancel = false; m_cancel = false;
scoped_limits scoped_rlimit(m_s.rlimit()); scoped_limits scoped_rlimit(m_s.rlimit());
vector<reslimit> limits;
ptr_vector<conquer> solvers; ptr_vector<conquer> solvers;
int finished_id = -1; int finished_id = -1;
std::string ex_msg; std::string ex_msg;
@ -445,20 +458,21 @@ lbool ccc::search() {
lbool result = l_undef; lbool result = l_undef;
m_decisions.reset(); m_decisions.reset();
cuber cuber(*this);
m_num_conquer = m_s.m_config.m_num_threads; m_num_conquer = m_s.m_config.m_num_threads;
int num_threads = 1 + m_num_conquer; // for ccc-infinity only two threads. int num_threads = 1 + m_num_conquer; // for ccc-infinity only two threads.
for (int i = 1; i < num_threads; ++i) { for (int i = 1; i < num_threads; ++i) {
limits.push_back(reslimit());
m_s.m_params.set_uint("random_seed", m_s.m_rand()); m_s.m_params.set_uint("random_seed", m_s.m_rand());
conquer* s1 = alloc(conquer, *this, m_s.m_params, limits.back(), i); conquer* s1 = alloc(conquer, *this, m_s.m_params, i);
solvers.push_back(s1); solvers.push_back(s1);
s1->s.copy(m_s); s1->s.copy(m_s);
scoped_rlimit.push_child(&(s1->s.rlimit())); scoped_rlimit.push_child(&(s1->m_limit));
m_decisions.push_back(queue<decision>()); m_decisions.push_back(queue<decision>());
} }
for (unsigned i = 1; i < m_num_conquer; ++i) { for (unsigned i = 1; i < m_num_conquer; ++i) {
m_free_threads.push_back(i); cuber.m_free_threads.push_back(i);
} }
#pragma omp parallel for #pragma omp parallel for
@ -466,7 +480,7 @@ lbool ccc::search() {
try { try {
lbool r = l_undef; lbool r = l_undef;
if (i == 0) { if (i == 0) {
r = cube(); r = cuber.search();
} }
else { else {
r = solvers[i-1]->search(); r = solvers[i-1]->search();
@ -482,7 +496,7 @@ lbool ccc::search() {
} }
if (first) { if (first) {
for (unsigned j = 0; j < solvers.size(); ++j) { for (unsigned j = 0; j < solvers.size(); ++j) {
solvers[j]->s.rlimit().cancel(); solvers[j]->m_limit.cancel();
} }
// cancel lookahead solver: // cancel lookahead solver:
m_cancel = true; m_cancel = true;

35
src/sat/sat_ccc.h
View file

@ -62,6 +62,7 @@ namespace sat {
struct stats { struct stats {
unsigned m_spawn_closed; unsigned m_spawn_closed;
unsigned m_spawn_opened;
unsigned m_cdcl_closed; unsigned m_cdcl_closed;
stats() { reset(); } stats() { reset(); }
void reset() { void reset() {
@ -70,12 +71,13 @@ namespace sat {
}; };
struct conquer { struct conquer {
ccc& super; reslimit m_limit;
ccc& m_ccc;
solver s; solver s;
svector<decision> decisions; svector<decision> decisions;
unsigned thread_id; unsigned thread_id;
bool m_spawned; bool m_spawned;
conquer(ccc& super, params_ref const& p, reslimit& l, unsigned tid): super(super), s(p, l), thread_id(tid), m_spawned(false) {} conquer(ccc& super, params_ref const& p, unsigned tid): m_ccc(super), s(p, m_limit), thread_id(tid), m_spawned(false) {}
lbool search(); lbool search();
bool cube_decision(); bool cube_decision();
@ -85,27 +87,35 @@ namespace sat {
void replay_decisions(); void replay_decisions();
}; };
struct cuber {
ccc& m_ccc;
lookahead lh;
unsigned m_branch_id;
unsigned m_last_closure_level;
unsigned_vector m_free_threads;
svector<decision> decisions;
cuber(ccc& c);
lbool search();
lbool research();
bool get_solved();
void update_closure_level(decision const& d, int offset);
unsigned spawn_conquer();
void free_conquer(unsigned thread_id);
};
solver& m_s; solver& m_s;
queue<solution> m_solved; queue<solution> m_solved;
vector<queue<decision> > m_decisions; vector<queue<decision> > m_decisions;
unsigned m_num_conquer; unsigned m_num_conquer;
model m_model; model m_model;
volatile bool m_cancel; volatile bool m_cancel;
unsigned m_branch_id;
unsigned_vector m_free_threads;
unsigned m_last_closure_level;
::statistics m_lh_stats; ::statistics m_lh_stats;
stats m_ccc_stats; stats m_ccc_stats;
lbool cube();
lbool cube(svector<decision>& decisions, lookahead& lh);
void put_decision(decision const& d); void put_decision(decision const& d);
bool get_solved(svector<decision>& decisions);
bool get_decision(unsigned thread_id, decision& d); bool get_decision(unsigned thread_id, decision& d);
void update_closure_level(decision const& d, int offset);
static std::ostream& pp(std::ostream& out, svector<decision> const& v); static std::ostream& pp(std::ostream& out, svector<decision> const& v);
void push_model(unsigned v, bool sign); void push_model(unsigned v, bool sign);
@ -114,8 +124,6 @@ namespace sat {
void check_non_model(char const* fn, svector<decision> const& decisions); void check_non_model(char const* fn, svector<decision> const& decisions);
unsigned spawn_conquer(svector<decision> const& decisions);
void free_conquer(unsigned thread_id);
public: public:
@ -129,6 +137,7 @@ namespace sat {
st.copy(m_lh_stats); st.copy(m_lh_stats);
st.update("ccc-spawn-closed", m_ccc_stats.m_spawn_closed); st.update("ccc-spawn-closed", m_ccc_stats.m_spawn_closed);
st.update("ccc-cdcl-closed", m_ccc_stats.m_cdcl_closed); st.update("ccc-cdcl-closed", m_ccc_stats.m_cdcl_closed);
st.update("ccc-spawn-opened", m_ccc_stats.m_spawn_opened);
} }
}; };
} }