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remove priority queue for top-k lits and replace with simple linear scan. the PQ implementation backend still remains in case we want to switch back

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This commit is contained in:
Ilana Shapiro 2025-08-24 18:08:49 -07:00
parent 9bf74b5d2b
commit 58dc54e840
3 changed files with 33 additions and 42 deletions
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5
src/smt/smt_context.h
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@ -191,7 +191,7 @@ namespace smt {
unsigned_vector m_lit_occs; //!< occurrence count of literals
svector<bool_var_data> m_bdata; //!< mapping bool_var -> data
svector<double> m_activity;
updatable_priority_queue::priority_queue<bool_var, double> m_pq_scores;
// updatable_priority_queue::priority_queue<bool_var, double> m_pq_scores;
struct lit_node : dll_base<lit_node> {
literal lit;
@ -199,7 +199,6 @@ namespace smt {
};
lit_node* m_dll_lits;
// svector<std::array<double, 2>> m_lit_scores;
svector<double> m_lit_scores[2];
clause_vector m_aux_clauses;
@ -952,7 +951,7 @@ namespace smt {
e = 0;
for (auto& e : m_lit_scores[1])
e = 0;
m_pq_scores.clear(); // Clear the priority queue heap as well
// m_pq_scores.clear(); // Clear the priority queue heap as well
}
double get_score(literal l) const {
return m_lit_scores[l.sign()][l.var()];

12
src/smt/smt_internalizer.cpp
View file

@ -1532,14 +1532,6 @@ namespace smt {
}}
}
// void context::add_scores(unsigned n, literal const* lits) {
// for (unsigned i = 0; i < n; ++i) {
// auto lit = lits[i];
// unsigned v = lit.var();
// m_lit_scores[v][lit.sign()] += 1.0 / n;
// }
// }
void context::add_scores(unsigned n, literal const* lits) {
for (unsigned i = 0; i < n; ++i) {
auto lit = lits[i];
@ -1547,8 +1539,8 @@ namespace smt {
m_lit_scores[lit.sign()][v] += 1.0 / n;
auto new_score = m_lit_scores[0][v] * m_lit_scores[1][v];
m_pq_scores.set(v, new_score);
// auto new_score = m_lit_scores[0][v] * m_lit_scores[1][v];
// m_pq_scores.set(v, new_score);
}
}

58
src/smt/smt_parallel.cpp
View file

@ -560,47 +560,47 @@ namespace smt {
}
expr_ref_vector parallel::worker::get_split_atoms() {
#if false
unsigned k = 2;
// auto candidates = ctx->m_pq_scores.get_heap();
auto candidates = ctx->m_lit_scores;
std::vector<std::pair<double, expr*>> top_k; // will hold at most k elements
for (bool_var v = 0; v < ctx->get_num_bool_vars(); ++v) {
if (ctx->get_assignment(v) != l_undef)
continue;
expr* e = ctx->bool_var2expr(v);
if (!e)
continue;
auto v_score = ctx->m_lit_scores[0][v] * ctx->m_lit_scores[1][v];
// if v_score is maximal then v is our split atom..
double score = ctx->m_lit_scores[0][v] * ctx->m_lit_scores[1][v];
// decay the scores
ctx->m_lit_scores[0][v] /= 2;
ctx->m_lit_scores[1][v] /= 2;
}
#endif
unsigned k = 2;
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; });
// insert into top_k. linear scan since k is very small
if (top_k.size() < k) {
top_k.push_back({score, e});
} else {
// find the smallest in top_k and replace if we found a new min
size_t min_idx = 0;
for (size_t i = 1; i < k; ++i)
if (top_k[i].first < top_k[min_idx].first)
min_idx = i;
if (score > top_k[min_idx].first) {
top_k[min_idx] = {score, e};
}
}
}
expr_ref_vector top_lits(m);
for (const auto& node: candidates) {
if (ctx->get_assignment(node.key) != l_undef)
continue;
if (m_config.m_cube_initial_only && node.key >= m_num_initial_atoms) {
LOG_WORKER(2, " Skipping non-initial atom from cube: " << node.key << "\n");
continue; // skip non-initial atoms if configured to do so
}
expr* e = ctx->bool_var2expr(node.key);
if (!e)
continue;
top_lits.push_back(expr_ref(e, m));
if (top_lits.size() >= k)
break;
}
IF_VERBOSE(3, verbose_stream() << "top literals " << top_lits << " head size " << ctx->m_pq_scores.size() << " num vars " << ctx->get_num_bool_vars() << "\n");
for (auto& p : top_k)
top_lits.push_back(expr_ref(p.second, m));
IF_VERBOSE(3, verbose_stream() << "top literals " << top_lits << " head size " << ctx->m_lit_scores->size() << " num vars " << ctx->get_num_bool_vars() << "\n");
return top_lits;
}