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add plateau option

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This commit is contained in:
Nikolaj Bjorner 2025-01-14 13:54:20 -08:00
parent 648cf9602e
commit 8515cebd19
2 changed files with 32 additions and 0 deletions
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27
src/ast/sls/sls_arith_base.cpp
View file

@ -2698,24 +2698,49 @@ namespace sls {
auto score = lookahead(e, false);
TRACE("arith_verbose", tout << "lookahead " << v << " " << mk_bounded_pp(e, m) << " := " << delta + old_value << " " << score << " (" << m_best_score << ")\n";);
if (score > m_best_score) {
m_tabu_set = 0;
m_best_score = score;
m_best_value = new_value;
m_best_expr = e;
}
else if (m_config.allow_plateau && score == m_best_score && !in_tabu_set(e, new_value)) {
m_best_score = score;
m_best_expr = e;
m_best_value = new_value;
insert_tabu_set(e, num_t(1));
}
// revert back to old value
update_args_value(v, old_value);
}
template<typename num_t>
bool arith_base<num_t>::in_tabu_set(expr* e, num_t const& n) {
uint64_t h = hash_u_u(e->get_id(), n.hash());
return (m_tabu_set & (1ull << (h & 64ull))) != 0;
}
template<typename num_t>
void arith_base<num_t>::insert_tabu_set(expr* e, num_t const& n) {
uint64_t h = hash_u_u(e->get_id(), n.hash());
m_tabu_set |= (1ull << (h & 64ull));
}
template<typename num_t>
void arith_base<num_t>::lookahead_bool(expr* e) {
bool b = get_bool_value(e);
set_bool_value(e, !b);
auto score = lookahead(e, false);
if (score > m_best_score) {
m_tabu_set = 0;
m_best_score = score;
m_best_expr = e;
}
else if (m_config.allow_plateau && score == m_best_score && !in_tabu_set(e, num_t(1))) {
m_best_score = score;
m_best_expr = e;
insert_tabu_set(e, num_t(1));
}
set_bool_value(e, b);
lookahead(e, false);
}
@ -2877,6 +2902,7 @@ namespace sls {
m_best_value = value(v) + delta;
break;
}
case arith_move_type::hillclimb_plateau:
case arith_move_type::hillclimb: {
for (unsigned i = 0; i < sz; ++i)
add_lookahead(info, vars[(start + i) % sz]);
@ -2885,6 +2911,7 @@ namespace sls {
std::stable_sort(m_updates.begin(), m_updates.end(), [](auto const& a, auto const& b) { return a.m_var < b.m_var || (a.m_var == b.m_var && a.m_delta < b.m_delta); });
m_last_expr = nullptr;
sz = m_updates.size();
flet<bool> _allow_plateau(m_config.allow_plateau, t == arith_move_type::hillclimb_plateau);
for (unsigned i = 0; i < sz; ++i) {
auto const& [v, delta, score] = m_updates[(start + i) % m_updates.size()];
lookahead_num(v, delta);

5
src/ast/sls/sls_arith_base.h
View file

@ -29,6 +29,7 @@ namespace sls {
enum arith_move_type {
hillclimb,
hillclimb_plateau,
random_update,
random_inc_dec
};
@ -66,6 +67,7 @@ namespace sls {
unsigned restart_next = 1000;
unsigned restart_init = 1000;
bool arith_use_lookahead = false;
bool allow_plateau = false;
};
struct stats {
@ -331,7 +333,10 @@ namespace sls {
expr_mark m_is_root;
unsigned m_touched = 1;
sat::bool_var_set m_fixed_atoms;
uint64_t m_tabu_set = 0;
bool in_tabu_set(expr* e, num_t const& n);
void insert_tabu_set(expr* e, num_t const& n);
bool_info& get_bool_info(expr* e);
bool get_bool_value(expr* e);
bool get_bool_value_rec(expr* e);