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share lemmas, learn from unsat core, try to debug a couple of things, there was a subtle bug that i have a hard time repro'ing

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Ilana Shapiro 2025-08-05 22:27:25 -07:00
parent 723de8d2a4
commit 58e312190d
1 changed files with 90 additions and 80 deletions
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170
src/smt/smt_parallel.cpp
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@ -52,38 +52,43 @@ namespace smt {
if (!m.inc())
return; // stop if the main context is cancelled
switch (check_cube(cube)) {
case l_undef: {
// 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.
vector<expr_ref_vector> returned_cubes;
returned_cubes.push_back(cube);
auto split_atoms = get_split_atoms();
b.return_cubes(l2g, returned_cubes, split_atoms);
break;
}
case l_true: {
model_ref mdl;
ctx->get_model(mdl);
b.set_sat(l2g, *mdl);
return;
}
case l_false: {
// if unsat core only contains (external) assumptions (i.e. all the unsat core are asms), then unsat and return as this does NOT depend on cubes
// otherwise, extract lemmas that can be shared (units (and unsat core?)).
// share with batch manager.
// process next cube.
auto const& unsat_core = ctx->unsat_core();
// If the unsat core only contains assumptions,
// unsatisfiability does not depend on the current cube and the entire problem is unsat.
if (any_of(unsat_core, [&](expr* e) { return asms.contains(e); })) {
b.set_unsat(l2g, ctx->unsat_core());
case l_undef: {
// 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.
vector<expr_ref_vector> returned_cubes;
returned_cubes.push_back(cube);
auto split_atoms = get_split_atoms();
b.return_cubes(l2g, returned_cubes, split_atoms);
break;
}
case l_true: {
std::cout << "Worker " << id << " found sat cube: " << mk_pp(mk_and(cube), m) << "\n";
model_ref mdl;
ctx->get_model(mdl);
b.set_sat(l2g, *mdl);
return;
}
// 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.
break;
}
case l_false: {
// if unsat core only contains (external) assumptions (i.e. all the unsat core are asms), then unsat and return as this does NOT depend on cubes
// otherwise, extract lemmas that can be shared (units (and unsat core?)).
// share with batch manager.
// process next cube.
expr_ref_vector const& unsat_core = ctx->unsat_core();
// If the unsat core only contains assumptions,
// unsatisfiability does not depend on the current cube and the entire problem is unsat.
if (all_of(unsat_core, [&](expr* e) { return asms.contains(e); })) {
std::cout << "Worker " << id << " determined formula unsat";
b.set_unsat(l2g, unsat_core);
return;
}
// 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.
std::cout << "Worker " << id << " found unsat cube: " << mk_pp(mk_and(cube), m) << "\n";
b.share_lemma(l2g, mk_not(mk_and(unsat_core)));
// share_units();
break;
}
}
}
}
@ -99,6 +104,57 @@ 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::batch_manager::share_lemma(ast_translation& l2g, expr* lemma) {
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?
}
// PUT THE LOGIC FOR LEARNING FROM UNSAT CORE HERE IF THE CUBE INTERSECTS WITH IT!!!
// THERE IS AN EDGE CASE: IF ALL THE CUBES ARE UNSAT, BUT DEPEND ON NONEMPTY ASSUMPTIONS, NEED TO TAKE THE UNION OF THESE ASMS WHEN LEARNING FROM UNSAT CORE
@ -155,10 +211,7 @@ namespace smt {
std::scoped_lock lock(mux);
if (l_false == m_result)
return;
m_result = l_false;
expr_ref_vector g_core(l2g.to());
for (auto& e : unsat_core)
g_core.push_back(l2g(e));
m_result = l_false;
p.ctx.m_unsat_core.reset();
for (expr* e : unsat_core)
p.ctx.m_unsat_core.push_back(l2g(e));
@ -203,7 +256,6 @@ namespace smt {
}
#endif
// CALL GET_SPLIT_ATOMS AS ARGUMENT TO RETURN_CUBES
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);
for (auto & c : cubes) {
@ -229,7 +281,7 @@ namespace smt {
// TODO: avoid making m_cubes too large.
// QUESTION: do we need to check if any split_atoms are already in the cubes in m_cubes??
for (auto& atom : split_atoms) {
expr_ref g_atom(l2g.from());
expr_ref g_atom(l2g.to());
g_atom = l2g(atom);
if (m_split_atoms.contains(g_atom))
continue;
@ -244,7 +296,7 @@ namespace smt {
}
expr_ref_vector parallel::worker::get_split_atoms() {
unsigned k = 1;
unsigned k = 2;
auto candidates = ctx->m_pq_scores.get_heap();
std::sort(candidates.begin(), candidates.end(),
@ -307,50 +359,8 @@ namespace smt {
lbool parallel::operator()(expr_ref_vector const& asms) {
std::cout << "Parallel solving with " << asms.size() << " assumptions." << std::endl;
flet<unsigned> _nt(ctx.m_fparams.m_threads, 1);
return new_check(asms);
// 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");
// };
}
}