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fix iterative deepening bug: unsolved cube needs to get re-enqueued even if we don't split it further

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This commit is contained in:
Ilana Shapiro 2025-08-29 10:30:15 -07:00
parent 1fae0dea16
commit a42d21fe80
2 changed files with 15 additions and 14 deletions
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25
src/smt/smt_parallel.cpp
View file

@ -111,8 +111,9 @@ namespace smt {
const double factor = 1; // can tune for multiple of avg hardness later
bool should_split = cube_hardness >= avg_hardness * factor;
LOG_WORKER(1, " cube hardness: " << cube_hardness << " avg: " << avg_hardness << " should-split: " << should_split << "\n");
if (should_split)
b.return_cubes(m_l2g, returned_cubes, split_atoms);
// we still need to call return_cubes, even if we don't split, since we need to re-enqueue the current unsolved cube to the batch manager!
// should_split tells return_cubes whether to further split the unsolved cube.
b.return_cubes(m_l2g, returned_cubes, split_atoms, should_split);
} else {
b.return_cubes(m_l2g, returned_cubes, split_atoms);
}
@ -328,7 +329,9 @@ namespace smt {
void parallel::batch_manager::get_cubes(ast_translation& g2l, vector<expr_ref_vector>& cubes) {
std::scoped_lock lock(mux);
if (m_cubes.size() == 1 && m_cubes[0].empty()) {
if (m_config.m_beam_search) {
} else if (m_cubes.size() == 1 && m_cubes[0].empty()) {
// special initialization: the first cube is emtpy, have the worker work on an empty cube.
cubes.push_back(expr_ref_vector(g2l.to()));
return;
@ -488,7 +491,7 @@ namespace smt {
------------------------------------------------------------------------------------------------------------------------------------------------------------
Final thought (do this!): use greedy strategy by a policy when C_batch, A_batch, A_worker are "small". -- want to do this. switch to frugal strategy after reaching size limit
*/
void parallel::batch_manager::return_cubes(ast_translation& l2g, vector<expr_ref_vector>const& C_worker, expr_ref_vector const& A_worker) {
void parallel::batch_manager::return_cubes(ast_translation& l2g, vector<expr_ref_vector>const& C_worker, expr_ref_vector const& A_worker, const bool should_split) {
// SASSERT(!m_config.never_cube());
auto atom_in_cube = [&](expr_ref_vector const& cube, expr* atom) {
@ -572,7 +575,6 @@ namespace smt {
expr_ref_vector g_cube(l2g.to());
for (auto& atom : c)
g_cube.push_back(l2g(atom));
unsigned start = m_cubes.size(); // update start after adding each cube so we only process the current cube being added
if (m_config.m_depth_splitting_only || m_config.m_iterative_deepening) {
// need to add the depth set if it doesn't exist yet
@ -610,7 +612,8 @@ namespace smt {
expr_ref g_atom(l2g(A_worker[i]), l2g.to());
if (!m_split_atoms.contains(g_atom))
m_split_atoms.push_back(g_atom);
if (m_config.m_depth_splitting_only || m_config.m_iterative_deepening) {
if (should_split && (m_config.m_depth_splitting_only || m_config.m_iterative_deepening)) {
IF_VERBOSE(1, verbose_stream() << " splitting worker cubes on new atom " << mk_bounded_pp(g_atom, m, 3) << "\n");
add_split_atom_deepest_cubes(g_atom);
} else {
add_split_atom(g_atom, initial_m_cubes_size);
@ -645,7 +648,7 @@ namespace smt {
double score_ratio = INFINITY; // score_pos / score_neg;
LOG_WORKER(0, " backbone candidate: " << mk_bounded_pp(candidate, m, 3) << " score_pos " << score_pos << " score_neg " << score_neg << "\n");
LOG_WORKER(1, " backbone candidate: " << mk_bounded_pp(candidate, m, 3) << " score_pos " << score_pos << " score_neg " << score_neg << "\n");
// if score_neg is zero (and thus score_pos > 0 since at this point score_pos != score_neg)
// then not(e) is a backbone candidate with score_ratio=infinity
@ -682,8 +685,8 @@ namespace smt {
backbone_candidates.push_back(p.second);
for (expr* e : backbone_candidates)
LOG_WORKER(0, "selected backbone candidate: " << mk_bounded_pp(e, m, 3) << " head size " << ctx->m_lit_scores->size() << " num vars " << ctx->get_num_bool_vars() << "\n");
LOG_WORKER(1, "selected backbone candidate: " << mk_bounded_pp(e, m, 3) << " head size " << ctx->m_lit_scores->size() << " num vars " << ctx->get_num_bool_vars() << "\n");
return backbone_candidates;
}
@ -719,12 +722,12 @@ namespace smt {
asms.shrink(sz); // restore assumptions
LOG_WORKER(0, " BACKBONE CHECK RESULT: " << r << "\n");
LOG_WORKER(1, " BACKBONE CHECK RESULT: " << r << "\n");
if (r == l_false) {
// c must be true in all models → backbone
auto core = ctx->unsat_core();
LOG_WORKER(0, "core: " << core << "\n");
LOG_WORKER(1, "core: " << core << "\n");
if (core.size() == 1) {
expr* e = core.get(0);
backbones.push_back(mk_not(m, e));

4
src/smt/smt_parallel.h
View file

@ -66,8 +66,6 @@ namespace smt {
stats m_stats;
expr_ref_vector m_split_atoms; // atoms to split on
vector<expr_ref_vector> m_cubes;
updatable_priority_queue::priority_queue<expr_ref_vector, double> m_cubes_pq;
std::map<unsigned, vector<expr_ref_vector>> m_cubes_depth_sets; // map<vec<cube>> contains sets of cubes, key is depth/size of cubes in the set
unsigned m_max_batch_size = 10;
unsigned m_exception_code = 0;
@ -109,7 +107,7 @@ namespace smt {
// worker threads return unprocessed cubes to the batch manager together with split literal candidates.
// the batch manager re-enqueues unprocessed cubes and optionally splits them using the split_atoms returned by this and workers.
//
void return_cubes(ast_translation& l2g, vector<expr_ref_vector>const& cubes, expr_ref_vector const& split_atoms);
void return_cubes(ast_translation& l2g, vector<expr_ref_vector>const& cubes, expr_ref_vector const& split_atoms, const bool should_split=true);
void report_assumption_used(ast_translation& l2g, expr* assumption);
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);