[CP-SAT] enable violation_ls by default

ortools/sat/cp_model_lns.h

@@ -575,7 +575,7 @@ class ConstraintGraphNeighborhoodGenerator : public NeighborhoodGenerator {
 class DecompositionGraphNeighborhoodGenerator : public NeighborhoodGenerator {
  public:
   explicit DecompositionGraphNeighborhoodGenerator(
-      NeighborhoodGeneratorHelper const* helper, const std::string& name)
+      NeighborhoodGeneratorHelper const* helper, absl::string_view name)
       : NeighborhoodGenerator(name, helper) {}
   Neighborhood Generate(const CpSolverResponse& initial_solution,
                         double difficulty, absl::BitGenRef random) final;
@@ -734,7 +734,7 @@ class SlicePackingNeighborhoodGenerator : public NeighborhoodGenerator {
 class RoutingRandomNeighborhoodGenerator : public NeighborhoodGenerator {
  public:
   RoutingRandomNeighborhoodGenerator(NeighborhoodGeneratorHelper const* helper,
-                                     const std::string& name)
+                                     absl::string_view name)
       : NeighborhoodGenerator(name, helper) {}
 
   Neighborhood Generate(const CpSolverResponse& initial_solution,
@@ -746,7 +746,7 @@ class RoutingRandomNeighborhoodGenerator : public NeighborhoodGenerator {
 class RoutingPathNeighborhoodGenerator : public NeighborhoodGenerator {
  public:
   RoutingPathNeighborhoodGenerator(NeighborhoodGeneratorHelper const* helper,
-                                   const std::string& name)
+                                   absl::string_view name)
       : NeighborhoodGenerator(name, helper) {}
 
   Neighborhood Generate(const CpSolverResponse& initial_solution,

ortools/sat/cp_model_solver.cc

@@ -3452,13 +3452,16 @@ void SolveCpModelParallel(const CpModelProto& model_proto,
             shared.incomplete_solutions.get(), "rins/rens"),
         params, helper, &shared));
   }
-
+  const int num_incomplete_solvers =
+      params.num_workers() - num_full_problem_solvers;
   const LinearModel* linear_model = global_model->Get<LinearModel>();
-  if (params.num_violation_ls() > 0 && !params.interleave_search() &&
-      model_proto.has_objective()) {
-    const int num_violation_ls = params.test_feasibility_jump()
-                                     ? params.num_workers()
-                                     : params.num_violation_ls();
+  if (!params.interleave_search() && model_proto.has_objective()) {
+    int num_violation_ls = params.has_num_violation_ls()
+                               ? params.num_violation_ls()
+                               : num_incomplete_solvers / 8 + 1;
+    if (params.test_feasibility_jump()) {
+      num_violation_ls = params.num_workers();
+    }
     for (int i = 0; i < num_violation_ls; ++i) {
       SatParameters local_params = params;
       local_params.set_random_seed(ValidSumSeed(params.random_seed(), i));

ortools/sat/diffn_cuts.cc

@@ -24,6 +24,7 @@
 #include "absl/base/attributes.h"
 #include "absl/log/check.h"
 #include "absl/strings/str_cat.h"
+#include "absl/strings/string_view.h"
 #include "absl/types/span.h"
 #include "ortools/base/stl_util.h"
 #include "ortools/base/strong_vector.h"
@@ -136,7 +137,7 @@ struct DiffnEnergyEvent : DiffnBaseEvent {
 
 void GenerateNoOverlap2dEnergyCut(
     const std::vector<std::vector<LiteralValueValue>>& energies,
-    absl::Span<int> rectangles, const std::string& cut_name, Model* model,
+    absl::Span<int> rectangles, absl::string_view cut_name, Model* model,
     LinearConstraintManager* manager, SchedulingConstraintHelper* x_helper,
     SchedulingConstraintHelper* y_helper,
     SchedulingDemandHelper* y_demands_helper) {
@@ -295,7 +296,7 @@ void GenerateNoOverlap2dEnergyCut(
         add_energy_to_name = true;
       }
     }
-    std::string full_name = cut_name;
+    std::string full_name(cut_name);
     if (add_opt_to_name) full_name.append("_optional");
     if (add_quadratic_to_name) full_name.append("_quadratic");
     if (add_energy_to_name) full_name.append("_energy");
@@ -401,7 +402,7 @@ std::string DiffnCtEvent::DebugString() const {
 //
 // TODO(user): merge with Packing cuts.
 void GenerateNoOvelap2dCompletionTimeCutsWithEnergy(
-    const std::string& cut_name, std::vector<DiffnCtEvent> events,
+    absl::string_view cut_name, std::vector<DiffnCtEvent> events,
     bool use_lifting, bool skip_low_sizes, Model* model,
     LinearConstraintManager* manager) {
   TopNCuts top_n_cuts(5);
@@ -548,7 +549,7 @@ void GenerateNoOvelap2dCompletionTimeCutsWithEnergy(
         add_energy_to_name |= event.use_energy;
         cut.AddTerm(event.x_end, event.energy_min * best_capacity);
       }
-      std::string full_name = cut_name;
+      std::string full_name(cut_name);
       if (is_lifted) full_name.append("_lifted");
       if (add_energy_to_name) full_name.append("_energy");
       top_n_cuts.AddCut(cut.Build(), full_name, manager->LpValues());

ortools/sat/precedences.h

@@ -14,9 +14,11 @@
 #ifndef OR_TOOLS_SAT_PRECEDENCES_H_
 #define OR_TOOLS_SAT_PRECEDENCES_H_
 
+#include <algorithm>
 #include <cstdint>
 #include <deque>
 #include <functional>
+#include <utility>
 #include <vector>
 
 #include "absl/container/inlined_vector.h"