mirrors/z3
3
0
Fork 0
mirror of https://github.com/Z3Prover/z3 synced 2025-08-26 21:16:02 +00:00
Code Activity

chipping away at the new code structure

Browse source
This commit is contained in:
Ilana Shapiro 2025-08-04 22:56:38 -07:00
parent e520a42a05
commit 3982b291a3
2 changed files with 64 additions and 385 deletions
Download patch file Download diff file Expand all files Collapse all files

438
src/smt/smt_parallel.cpp
View file

@ -40,7 +40,6 @@ namespace smt {
namespace smt {
void parallel::worker::run() {
ast_translation tr(ctx->m, m);
while (m.inc()) {
@ -56,10 +55,13 @@ namespace smt {
// return unprocessed cubes to the batch manager
// add a split literal to the batch manager.
// optionally process other cubes and delay sending back unprocessed cubes to batch manager.
b.m_cubes.push_back(cube); // TODO: add access funcs for m_cubes
break;
case l_true: {
model_ref mdl;
ctx->get_model(mdl);
if (mdl)
ctx->set_model(mdl->translate(tr));
//b.set_sat(tr, *mdl);
return;
}
@ -68,6 +70,9 @@ namespace smt {
// otherwise, extract lemmas that can be shared (units (and unsat core?)).
// share with batch manager.
// process next cube.
ctx->m_unsat_core.reset();
for (expr* e : pctx.unsat_core()) // TODO: move this logic to the batch manager since this is per-thread
ctx->m_unsat_core.push_back(tr(e));
break;
}
}
@ -75,7 +80,6 @@ namespace smt {
}
parallel::worker::worker(parallel& p, context& _ctx, expr_ref_vector const& _asms): p(p), b(p.m_batch_manager), m_smt_params(_ctx.get_fparams()), asms(m) {
ast_translation g2l(_ctx.m, m);
for (auto e : _asms)
asms.push_back(g2l(e));
@ -85,8 +89,12 @@ namespace smt {
lbool parallel::worker::check_cube(expr_ref_vector const& cube) {
return l_undef;
for (auto& atom : cube) {
asms.push_back(atom);
}
lbool r = ctx->check(asms.size(), asms.data());
asms.shrink(asms.size() - cube.size());
return r;
}
void parallel::batch_manager::get_cubes(ast_translation& g2l, vector<expr_ref_vector>& cubes) {
@ -96,9 +104,8 @@ namespace smt {
cubes.push_back(expr_ref_vector(g2l.to()));
return;
}
// TODO adjust to number of worker threads runnin.
// if the size of m_cubes is less than m_max_batch_size/ num_threads, then return fewer cubes.
for (unsigned i = 0; i < m_max_batch_size && !m_cubes.empty(); ++i) {
for (unsigned i = 0; i < std::min(m_max_batch_size / p.num_threads, (unsigned)m_cubes.size()) && !m_cubes.empty(); ++i) {
auto& cube = m_cubes.back();
expr_ref_vector l_cube(g2l.to());
for (auto& e : cube) {
@ -109,6 +116,21 @@ namespace smt {
}
}
void parallel::batch_manager::set_sat(ast_translation& l2g, model& m) {
std::scoped_lock lock(mux);
if (m_result == l_true || m_result == l_undef) {
m_result = l_true;
return;
}
m_result = l_true;
for (auto& c : m_cubes) {
expr_ref_vector g_cube(l2g.to());
for (auto& e : c) {
g_cube.push_back(l2g(e));
}
share_lemma(l2g, mk_and(g_cube));
}
}
void parallel::batch_manager::return_cubes(ast_translation& l2g, vector<expr_ref_vector>const& cubes, expr_ref_vector const& split_atoms) {
std::scoped_lock lock(mux);
@ -120,6 +142,7 @@ namespace smt {
// TODO: split this g_cube on m_split_atoms that are not already in g_cube as literals.
m_cubes.push_back(g_cube);
}
// TODO: avoid making m_cubes too large.
for (auto& atom : split_atoms) {
expr_ref g_atom(l2g.from());
@ -136,9 +159,27 @@ namespace smt {
}
}
expr_ref_vector parallel::worker::get_split_atoms() {
unsigned k = 1;
auto candidates = ctx->m_pq_scores.get_heap();
std::sort(candidates.begin(), candidates.end(),
[](const auto& a, const auto& b) { return a.priority > b.priority; });
expr_ref_vector top_lits(m);
for (const auto& node : candidates) {
if (ctx->get_assignment(node.key) != l_undef) continue;
expr* e = ctx->bool_var2expr(node.key);
if (!e) continue;
top_lits.push_back(expr_ref(e, m));
if (top_lits.size() >= k) break;
}
return top_lits;
}
lbool parallel::new_check(expr_ref_vector const& asms) {
ast_manager& m = ctx.m;
{
scoped_limits sl(m.limit());
@ -146,6 +187,11 @@ namespace smt {
SASSERT(num_threads > 1);
for (unsigned i = 0; i < num_threads; ++i)
m_workers.push_back(alloc(worker, *this, ctx, asms));
// THIS WILL ALLOW YOU TO CANCEL ALL THE CHILD THREADS
// within the lexical scope of the code block, creates a data structure that allows you to push children
// objects to the limit object, so if someone cancels the parent object, the cancellation propagates to the children
// and that cancellation has the lifetime of the scope
for (auto w : m_workers)
sl.push_child(&(w->limit()));
@ -154,8 +200,7 @@ namespace smt {
for (unsigned i = 0; i < num_threads; ++i) {
threads[i] = std::thread([&, i]() {
m_workers[i]->run();
}
);
});
}
// Wait for all threads to finish
@ -177,12 +222,6 @@ namespace smt {
// try first sequential with a low conflict budget to make super easy problems cheap
// GET RID OF THIS, AND IMMEDIATELY SEND TO THE MULTITHREADED CHECKER
// THE FIRST BATCH OF CUBES IS EMPTY, AND WE WILL SET ALL THREADS TO WORK ON THE ORIGINAL FORMULA
unsigned max_c = std::min(thread_max_conflicts, 40u);
flet<unsigned> _mc(ctx.get_fparams().m_max_conflicts, max_c);
result = ctx.check(asms.size(), asms.data());
if (result != l_undef || ctx.m_num_conflicts < max_c) {
return result;
}
enum par_exception_kind {
DEFAULT_EX,
@ -226,77 +265,6 @@ namespace smt {
sl.push_child(&(new_m->limit()));
}
auto cube_pq = [&](context& ctx, expr_ref_vector& lasms, expr_ref& c) {
unsigned k = 3; // Number of top literals you want
ast_manager& m = ctx.get_manager();
// Get the entire fixed-size priority queue (it's not that big)
auto candidates = ctx.m_pq_scores.get_heap(); // returns vector<node<key, priority>>
// Sort descending by priority (higher priority first)
std::sort(candidates.begin(), candidates.end(),
[](const auto& a, const auto& b) { return a.priority > b.priority; });
expr_ref_vector conjuncts(m);
unsigned count = 0;
for (const auto& node : candidates) {
if (ctx.get_assignment(node.key) != l_undef) continue;
expr* e = ctx.bool_var2expr(node.key);
if (!e) continue;
expr_ref lit(e, m);
conjuncts.push_back(lit);
if (++count >= k) break;
}
c = mk_and(conjuncts);
lasms.push_back(c);
};
auto cube_score = [&](context& ctx, expr_ref_vector& lasms, expr_ref& c) {
vector<std::pair<expr_ref, double>> candidates;
unsigned k = 4; // Get top-k scoring literals
ast_manager& m = ctx.get_manager();
// Loop over first 100 Boolean vars
for (bool_var v = 0; v < 100; ++v) {
if (ctx.get_assignment(v) != l_undef) continue;
expr* e = ctx.bool_var2expr(v);
if (!e) continue;
literal lit(v, false);
double score = ctx.get_score(lit);
if (score == 0.0) continue;
candidates.push_back(std::make_pair(expr_ref(e, m), score));
}
// Sort all candidate literals descending by score
std::sort(candidates.begin(), candidates.end(),
[](auto& a, auto& b) { return a.second > b.second; });
// Clear c and build it as conjunction of top-k
expr_ref_vector conjuncts(m);
for (unsigned i = 0; i < std::min(k, (unsigned)candidates.size()); ++i) {
expr_ref lit = candidates[i].first;
conjuncts.push_back(lit);
}
// Build conjunction and store in c
c = mk_and(conjuncts);
// Add the single cube formula to lasms (not each literal separately)
lasms.push_back(c);
};
obj_hashtable<expr> unit_set;
expr_ref_vector unit_trail(ctx.m);
unsigned_vector unit_lim;
@ -338,281 +306,6 @@ namespace smt {
IF_VERBOSE(1, verbose_stream() << "(smt.thread :units " << sz << ")\n");
};
std::mutex mux;
// Lambda defining the work each SMT thread performs
auto worker_thread = [&](int i, vector<expr_ref_vector>& cube_batch) {
try {
// Get thread-specific context and AST manager
context& pctx = *pctxs[i];
ast_manager& pm = *pms[i];
// Initialize local assumptions and cube
expr_ref_vector lasms(pasms[i]);
vector<lbool> results;
for (expr_ref_vector& cube : cube_batch) {
expr_ref_vector lasms_copy(lasms); // DON'T NEED TO COPY, JUST SHRINK BACK TO ORIGINAL SIZE
if (&cube.get_manager() != &pm) {
std::cerr << "Manager mismatch on cube: " << mk_bounded_pp(mk_and(cube), pm, 3) << "\n";
UNREACHABLE(); // or throw
}
for (expr* cube_lit : cube) {
lasms_copy.push_back(expr_ref(cube_lit, pm));
}
// Set the max conflict limit for this thread
pctx.get_fparams().m_max_conflicts = std::min(thread_max_conflicts, max_conflicts);
// Optional verbose logging
IF_VERBOSE(1, verbose_stream() << "(smt.thread " << i;
if (num_rounds > 0) verbose_stream() << " :round " << num_rounds;
verbose_stream() << " :cube " << mk_bounded_pp(mk_and(cube), pm, 3);
verbose_stream() << ")\n";);
lbool r = pctx.check(lasms_copy.size(), lasms_copy.data());
std::cout << "Thread " << i << " finished cube " << mk_bounded_pp(mk_and(cube), pm, 3) << " with result: " << r << "\n";
results.push_back(r);
}
lbool r = l_false;
for (lbool res : results) {
if (res == l_true) {
r = l_true;
} else if (res == l_undef) {
if (r == l_false)
r = l_undef;
}
}
auto cube_intersects_core = [&](expr* cube, const expr_ref_vector &core) {
expr_ref_vector cube_lits(pctx.m);
flatten_and(cube, cube_lits);
for (expr* lit : cube_lits)
if (core.contains(lit))
return true;
return false;
};
// Handle results based on outcome and conflict count
if (r == l_undef && pctx.m_num_conflicts >= max_conflicts)
; // no-op, allow loop to continue
else if (r == l_undef && pctx.m_num_conflicts >= thread_max_conflicts)
return; // quit thread early
// If cube was unsat and it's in the core, learn from it. i.e. a thread can be UNSAT because the cube c contradicted F. In this case learn the negation of the cube ¬c
// else if (r == l_false) {
// // IF_VERBOSE(1, verbose_stream() << "(smt.thread " << i << " :learn cube batch " << mk_bounded_pp(cube, pm, 3) << ")" << " unsat_core: " << pctx.unsat_core() << ")");
// for (expr* cube : cube_batch) { // iterate over each cube in the batch
// if (cube_intersects_core(cube, pctx.unsat_core())) {
// // IF_VERBOSE(1, verbose_stream() << "(pruning cube: " << mk_bounded_pp(cube, pm, 3) << " given unsat core: " << pctx.unsat_core() << ")");
// pctx.assert_expr(mk_not(mk_and(pctx.unsat_core())));
// }
// }
// }
// Begin thread-safe update of shared result state
// THIS SHOULD ALL BE HANDLED WITHIN THE BATCH MANAGER
// USING METHODS LIKE SET_UNSAT AND SET_SAT WHICH KILLS THE OTHER WORKER THREADS
bool first = false;
{
std::lock_guard<std::mutex> lock(mux);
if (finished_id == UINT_MAX) {
finished_id = i;
first = true;
result = r;
done = true;
}
if (!first && r != l_undef && result == l_undef) {
finished_id = i;
result = r;
}
else if (!first) return; // nothing new to contribute
}
// Cancel limits on other threads now that a result is known
// MOVE INSIDE BATCH MANAGER
for (ast_manager* m : pms) {
if (m != &pm) m->limit().cancel();
}
} catch (z3_error & err) {
if (finished_id == UINT_MAX) {
error_code = err.error_code();
ex_kind = ERROR_EX;
done = true;
}
} catch (z3_exception & ex) {
if (finished_id == UINT_MAX) {
ex_msg = ex.what();
ex_kind = DEFAULT_EX;
done = true;
}
} catch (...) {
if (finished_id == UINT_MAX) {
ex_msg = "unknown exception";
ex_kind = ERROR_EX;
done = true;
}
}
};
struct BatchManager {
std::mutex mtx;
vector<vector<expr_ref_vector>> batches;
unsigned batch_idx = 0;
unsigned batch_size = 1;
BatchManager(unsigned batch_size) : batch_size(batch_size) {}
// translate the next SINGLE batch of batch_size cubes to the thread
vector<expr_ref_vector> get_next_batch(
ast_manager &main_ctx_m,
ast_manager &thread_m
) {
std::lock_guard<std::mutex> lock(mtx);
vector<expr_ref_vector> cube_batch; // ensure bound to thread manager
if (batch_idx >= batches.size()) return cube_batch;
vector<expr_ref_vector> next_batch = batches[batch_idx];
for (const expr_ref_vector& cube : next_batch) {
expr_ref_vector translated_cube_lits(thread_m);
for (expr* lit : cube) {
// Translate each literal to the thread's manager
translated_cube_lits.push_back(translate(lit, main_ctx_m, thread_m)); // IF WE DO AST_TRANSLATION& g2l INSTEAD, THE AST MANAGER HANDLES THE TRANSLATION UNDER LOCK, THIS IS BETTER
}
cube_batch.push_back(translated_cube_lits);
}
++batch_idx;
return cube_batch;
}
// returns a list (vector) of cubes, where each cube is an expr_ref_vector of literals
// NOTE: THE HEAP IS THREAD SPECIFIC!!! SO DON'T QUERY FROM MAIN THREAD ALL THE TIME!!
// PASS IN THE CONTEXT OF THE THREAD WE WANT TO QUERY THE TOP K HEAP FROM!!
// ALSO, WE ARE GOING TO RETURN JUST THE TOP K LITS, NOT THE 2^K TOP CUBES
vector<expr_ref_vector> cube_batch_pq(context& ctx) {
unsigned k = 1; // generates 2^k cubes in the batch
ast_manager& m = ctx.get_manager();
auto candidates = ctx.m_pq_scores.get_heap();
std::sort(candidates.begin(), candidates.end(),
[](const auto& a, const auto& b) { return a.priority > b.priority; });
expr_ref_vector top_lits(m);
for (const auto& node : candidates) {
if (ctx.get_assignment(node.key) != l_undef) continue;
expr* e = ctx.bool_var2expr(node.key);
if (!e) continue;
top_lits.push_back(expr_ref(e, m));
if (top_lits.size() >= k) break;
}
// std::cout << "Top lits:\n";
// for (unsigned j = 0; j < top_lits.size(); ++j) {
// std::cout << " [" << j << "] " << mk_pp(top_lits[j].get(), m) << "\n";
// }
unsigned num_lits = top_lits.size();
unsigned num_cubes = 1 << num_lits; // 2^num_lits combinations
vector<expr_ref_vector> cube_batch;
for (unsigned mask = 0; mask < num_cubes; ++mask) {
expr_ref_vector cube_lits(m);
for (unsigned i = 0; i < num_lits; ++i) {
expr_ref lit(top_lits[i].get(), m);
if ((mask >> i) & 1)
cube_lits.push_back(mk_not(lit));
else
cube_lits.push_back(lit);
}
cube_batch.push_back(cube_lits);
}
std::cout << "Cubes out:\n";
for (unsigned j = 0; j < cube_batch.size(); ++j) {
std::cout << " [" << j << "]\n";
for (unsigned k = 0; k < cube_batch[j].size(); ++k) {
std::cout << " [" << k << "] " << mk_pp(cube_batch[j][k].get(), m) << "\n";
}
}
return cube_batch;
};
// returns a vector of new cubes batches. each cube batch is a vector of expr_ref_vector cubes
vector<vector<expr_ref_vector>> gen_new_batches(context& main_ctx) {
vector<vector<expr_ref_vector>> cube_batches;
// Get all cubes in the main context's manager
vector<expr_ref_vector> all_cubes = cube_batch_pq(main_ctx);
ast_manager &m = main_ctx.get_manager();
// Partition into batches
for (unsigned start = 0; start < all_cubes.size(); start += batch_size) {
vector<expr_ref_vector> batch;
unsigned end = std::min(start + batch_size, all_cubes.size());
for (unsigned j = start; j < end; ++j) {
batch.push_back(all_cubes[j]);
}
cube_batches.push_back(batch);
}
batch_idx = 0; // Reset index for next round
return cube_batches;
}
void check_for_new_batches(context& main_ctx) {
std::lock_guard<std::mutex> lock(mtx);
if (batch_idx >= batches.size()) {
batches = gen_new_batches(main_ctx);
}
}
};
BatchManager batch_manager(1);
// Thread scheduling loop
while (true) {
vector<std::thread> threads(num_threads);
batch_manager.check_for_new_batches(ctx);
// Launch threads
for (unsigned i = 0; i < num_threads; ++i) {
// [&, i] is the lambda's capture clause: capture all variables by reference (&) except i, which is captured by value.
threads[i] = std::thread([&, i]() {
while (!done) {
auto next_batch = batch_manager.get_next_batch(ctx.m, *pms[i]);
if (next_batch.empty()) break; // No more work
worker_thread(i, next_batch);
}
});
}
// Wait for all threads to finish
for (auto & th : threads) {
th.join();
}
// Stop if one finished with a result
if (done) break;
// Otherwise update shared state and retry
collect_units();
++num_rounds;
max_conflicts = (max_conflicts < thread_max_conflicts) ? 0 : (max_conflicts - thread_max_conflicts);
thread_max_conflicts *= 2;
}
// Gather statistics from all solver contexts
for (context* c : pctxs) {
c->collect_statistics(ctx.m_aux_stats);
@ -626,27 +319,6 @@ namespace smt {
}
}
// Handle result: translate model/unsat core back to main context
// THIS SHOULD CO INSIDE THE PARALLEL::WORKER::RUN FUNCTION
model_ref mdl;
context& pctx = *pctxs[finished_id];
ast_translation tr(*pms[finished_id], m);
switch (result) {
case l_true:
pctx.get_model(mdl);
if (mdl)
ctx.set_model(mdl->translate(tr));
break;
case l_false:
ctx.m_unsat_core.reset();
for (expr* e : pctx.unsat_core())
ctx.m_unsat_core.push_back(tr(e));
break;
default:
break;
}
return result;
}
}

9
src/smt/smt_parallel.h
View file

@ -24,6 +24,7 @@ namespace smt {
class parallel {
context& ctx;
unsigned num_threads;
class batch_manager {
ast_manager& m;
@ -71,6 +72,7 @@ namespace smt {
public:
worker(parallel& p, context& _ctx, expr_ref_vector const& _asms);
void run();
expr_ref_vector get_split_atoms();
void cancel() {
m.limit().cancel();
}
@ -88,7 +90,12 @@ namespace smt {
lbool new_check(expr_ref_vector const& asms);
public:
parallel(context& ctx): ctx(ctx), m_batch_manager(ctx.m, *this) {}
parallel(context& ctx) :
ctx(ctx),
num_threads(std::min(
(unsigned)std::thread::hardware_concurrency(),
ctx.get_fparams().m_threads)),
m_batch_manager(ctx.m, *this) {}
lbool operator()(expr_ref_vector const& asms);