always-cautious/ortools-clone
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

[CP-SAT] disambiguate shaving parameters

Browse Source
This commit is contained in:
Laurent Perron
2025-04-15 21:04:21 +02:00
parent 467091fe92
commit 3e1d3d7da9
4 changed files with 9 additions and 8 deletions
Download Patch File Download Diff File Expand all files Collapse all files

5
ortools/sat/cp_model_search.cc
View File

@@ -650,7 +650,8 @@ absl::flat_hash_map<std::string, SatParameters> GetNamedParameters(
new_params.set_search_branching(SatParameters::AUTOMATIC_SEARCH);
new_params.set_use_probing_search(true);
new_params.set_at_most_one_max_expansion_size(2);
const double dtime = base_params.shaving_search_deterministic_time();
// Use a small deterministic time to avoid spending too much time on
// shaving by default. The probing workers will increase it as needed.
new_params.set_shaving_search_deterministic_time(0.001);
if (base_params.use_dual_scheduling_heuristics()) {
AddExtraSchedulingPropagators(new_params);
@@ -660,8 +661,6 @@ absl::flat_hash_map<std::string, SatParameters> GetNamedParameters(
new_params.set_linearization_level(0);
strategies["probing_no_lp"] = new_params;
// Use the default deterministic time.
new_params.set_shaving_search_deterministic_time(dtime);
// We want to spend more time on the LP here.
new_params.set_linearization_level(2);
new_params.set_add_lp_constraints_lazily(false);

5
ortools/sat/integer_search.cc
View File

@@ -25,7 +25,6 @@
#include "absl/log/check.h"
#include "absl/log/log.h"
#include "absl/log/vlog_is_on.h"
#include "absl/meta/type_traits.h"
#include "absl/random/distributions.h"
#include "absl/strings/str_cat.h"
#include "absl/types/span.h"
@@ -1950,9 +1949,9 @@ SatSolver::Status ContinuousProber::Probe() {
// Update the use_shaving_ parameter.
// TODO(user): Currently, the heuristics is that we alternate shaving and
// not shaving, unless use_shaving_in_probing_search is false.
// not shaving, unless shaving_deterministic_time_in_probing_search is <= 0.
use_shaving_ =
parameters_.use_shaving_in_probing_search() ? !use_shaving_ : false;
parameters_.shaving_deterministic_time_in_probing_search() > 0.0;
trail_index_at_start_of_iteration_ = new_trail_index;
integer_trail_index_at_start_of_iteration_ = new_integer_trail_index;

1
ortools/sat/parameters_validation.cc
View File

@@ -88,6 +88,7 @@ std::string ValidateParameters(const SatParameters& params) {
TEST_IS_FINITE(restart_dl_average_ratio);
TEST_IS_FINITE(restart_lbd_average_ratio);
TEST_IS_FINITE(shared_tree_open_leaves_per_worker);
TEST_IS_FINITE(shaving_deterministic_time_in_probing_search);
TEST_IS_FINITE(shaving_search_deterministic_time);
TEST_IS_FINITE(strategy_change_increase_ratio);
TEST_IS_FINITE(symmetry_detection_deterministic_time_limit);

6
ortools/sat/sat_parameters.proto
View File

@@ -1054,8 +1054,10 @@ message SatParameters {
optional int32 probing_num_combinations_limit = 272 [default = 20000];
// Add a shaving phase (where the solver tries to prove that the lower or
// upper bound of a variable are infeasible) to the probing search.
optional bool use_shaving_in_probing_search = 204 [default = true];
// upper bound of a variable are infeasible) to the probing search. (<= 0
// disables it).
optional double shaving_deterministic_time_in_probing_search = 204
[default = 0.001];
// Specifies the amount of deterministic time spent of each try at shaving a
// bound in the shaving search.