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set up initial scaffolding for sharing clauses between threads and batch manager. needs some reworking/debug still

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This commit is contained in:
Ilana Shapiro 2025-08-12 11:47:31 -07:00
parent a32b7ba3f5
commit d864226402
2 changed files with 60 additions and 52 deletions
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94
src/smt/smt_parallel.cpp
View file

@ -98,8 +98,8 @@ namespace smt {
// TODO: can share lemmas here, such as new units and not(and(unsat_core)), binary clauses, etc.
// TODO: remember assumptions used in core so that they get used for the final core.
IF_VERBOSE(0, verbose_stream() << "Worker " << id << " found unsat cube\n");
b.share_lemma(l2g, mk_not(mk_and(unsat_core)));
// share_units();
b.collect_clause(l2g, id, mk_not(mk_and(unsat_core)));
share_units(l2g);
break;
}
}
@ -118,55 +118,53 @@ namespace smt {
ctx->set_random_seed(id + m_smt_params.m_random_seed);
}
void parallel::worker::share_units() {
// obj_hashtable<expr> unit_set;
// expr_ref_vector unit_trail(ctx.m);
// unsigned_vector unit_lim;
// for (unsigned i = 0; i < num_threads; ++i) unit_lim.push_back(0);
// // we just want to share lemmas and have a way of remembering how they are shared -- this is the next step
// // (this needs to be reworked)
// std::function<void(void)> collect_units = [&,this]() {
// //return; -- has overhead
// for (unsigned i = 0; i < num_threads; ++i) {
// context& pctx = *pctxs[i];
// pctx.pop_to_base_lvl();
// ast_translation tr(pctx.m, ctx.m);
// unsigned sz = pctx.assigned_literals().size();
// for (unsigned j = unit_lim[i]; j < sz; ++j) {
// literal lit = pctx.assigned_literals()[j];
// //IF_VERBOSE(0, verbose_stream() << "(smt.thread " << i << " :unit " << lit << " " << pctx.is_relevant(lit.var()) << ")\n";);
// if (!pctx.is_relevant(lit.var()))
// continue;
// expr_ref e(pctx.bool_var2expr(lit.var()), pctx.m);
// if (lit.sign()) e = pctx.m.mk_not(e);
// expr_ref ce(tr(e.get()), ctx.m);
// if (!unit_set.contains(ce)) {
// unit_set.insert(ce);
// unit_trail.push_back(ce);
// }
// }
// }
// unsigned sz = unit_trail.size();
// for (unsigned i = 0; i < num_threads; ++i) {
// context& pctx = *pctxs[i];
// ast_translation tr(ctx.m, pctx.m);
// for (unsigned j = unit_lim[i]; j < sz; ++j) {
// expr_ref src(ctx.m), dst(pctx.m);
// dst = tr(unit_trail.get(j));
// pctx.assert_expr(dst); // Assert that the conjunction of the assumptions in this unsat core is not satisfiable — prune it from future search
// }
// unit_lim[i] = pctx.assigned_literals().size();
// }
// IF_VERBOSE(1, verbose_stream() << "(smt.thread :units " << sz << ")\n");
// };
void parallel::worker::share_units(ast_translation& l2g) {
// Collect new units learned locally by this worker and send to batch manager
unsigned sz = ctx->assigned_literals().size();
for (unsigned j = shared_clause_limit; j < sz; ++j) { // iterate only over new literals since last sync -- QUESTION: I THINK THIS IS BUGGY BECAUSE THE SHARED CLAUSE LIMIT IS ONLY UPDATED (FOR ALL CLAUSE TYPES) WHEN WE GATHER NEW SHARED UNITS
literal lit = ctx->assigned_literals()[j];
expr_ref e(ctx->bool_var2expr(lit.var()), ctx->m); // turn literal into a Boolean expression
if (lit.sign())
e = ctx->m.mk_not(e); // negate if literal is negative
b.collect_clause(l2g, id, e);
}
}
void parallel::batch_manager::share_lemma(ast_translation& l2g, expr* lemma) {
void parallel::batch_manager::collect_clause(ast_translation& l2g, unsigned source_worker_id, expr* clause) {
std::scoped_lock lock(mux);
expr_ref g_lemma(l2g(lemma), l2g.to());
p.ctx.assert_expr(g_lemma); // QUESTION: where does this get shared with the local thread contexts? -- doesn't right now, we will build the scaffolding for this later!
expr* g_clause = l2g(clause);
if (!shared_clause_set.contains(g_clause)) {
shared_clause_set.insert(g_clause);
SharedClause sc{source_worker_id, g_clause};
shared_clause_trail.push_back(sc);
}
}
// QUESTION -- WHERE SHOULD WE CALL THIS?
void parallel::worker::collect_shared_clauses(ast_translation& g2l) {
expr_ref_vector new_clauses = b.return_shared_clauses(g2l, shared_clause_limit, id); // get new clauses from the batch manager
// iterate over new clauses and assert them in the local context
for (expr* e : new_clauses) {
expr_ref local_clause(e, g2l.to()); // e was already translated to the local context in the batch manager!!
ctx->assert_expr(local_clause); // assert the clause in the local context
IF_VERBOSE(0, verbose_stream() << "Worker " << id << " asserting shared clause: " << mk_bounded_pp(local_clause, m, 3) << "\n");
}
}
// get new clauses from the batch manager and assert them in the local context
expr_ref_vector parallel::batch_manager::return_shared_clauses(ast_translation& g2l, unsigned& worker_limit, unsigned worker_id) {
expr_ref_vector result(g2l.to());
{
std::scoped_lock lock(mux);
for (unsigned i = worker_limit; i < shared_clause_trail.size(); ++i) {
if (shared_clause_trail[i].source_worker_id == worker_id)
continue; // skip clauses from the requesting worker
expr_ref local_clause(g2l(shared_clause_trail[i].clause), g2l.to());
result.push_back(local_clause);
}
worker_limit = shared_clause_trail.size(); // update the worker limit to the end of the current trail
}
return result;
}
lbool parallel::worker::check_cube(expr_ref_vector const& cube) {

18
src/smt/smt_parallel.h
View file

@ -27,6 +27,11 @@ namespace smt {
context& ctx;
unsigned num_threads;
struct SharedClause {
unsigned source_worker_id;
expr* clause;
};
class batch_manager {
enum state {
is_running,
@ -45,12 +50,14 @@ namespace smt {
unsigned m_max_batch_size = 10;
unsigned m_exception_code = 0;
std::string m_exception_msg;
std::vector<SharedClause> shared_clause_trail; // store all shared clauses with worker IDs
obj_hashtable<expr> shared_clause_set; // for duplicate filtering on per-thread clause expressions
// called from batch manager to cancel other workers if we've reached a verdict
void cancel_workers() {
IF_VERBOSE(0, verbose_stream() << "Canceling workers\n");
for (auto& w : p.m_workers)
w->cancel();
w->cancel();
}
public:
@ -76,7 +83,8 @@ namespace smt {
//
void return_cubes(ast_translation& l2g, vector<expr_ref_vector>const& cubes, expr_ref_vector const& split_atoms);
void report_assumption_used(ast_translation& l2g, expr* assumption);
void share_lemma(ast_translation& l2g, expr* lemma);
void collect_clause(ast_translation& l2g, unsigned source_worker_id, expr* e);
expr_ref_vector return_shared_clauses(ast_translation& g2l, unsigned& worker_limit, unsigned worker_id);
lbool get_result() const;
};
@ -90,12 +98,15 @@ namespace smt {
scoped_ptr<context> ctx;
unsigned m_max_conflicts = 100;
unsigned m_num_shared_units = 0;
void share_units();
unsigned shared_clause_limit = 0; // remembers the index into shared_clause_trail marking the boundary between "old" and "new" clauses to share
void share_units(ast_translation& l2g);
lbool check_cube(expr_ref_vector const& cube);
public:
worker(unsigned id, parallel& p, expr_ref_vector const& _asms);
void run();
expr_ref_vector get_split_atoms();
void collect_shared_clauses(ast_translation& g2l);
void cancel() {
IF_VERBOSE(0, verbose_stream() << "Worker " << id << " canceling\n");
m.limit().cancel();
@ -122,7 +133,6 @@ namespace smt {
m_batch_manager(ctx.m, *this) {}
lbool operator()(expr_ref_vector const& asms);
};
}