cleanup cp-sat default search configurations

Author: lperron

ortools/flatzinc/cp_model_fz_solver.cc

@@ -1685,20 +1685,14 @@ void SolveFzWithCpModelProto(const fz::Model& fz_model,
     m.parameters.set_search_branching(SatParameters::AUTOMATIC_SEARCH);
     if (!p.search_all_solutions && p.ortools_mode) {
       m.parameters.set_interleave_search(true);
-      if (fz_model.objective() != nullptr) {
-        m.parameters.add_subsolvers("default_lp");
-        m.parameters.add_subsolvers(
-            m.proto.search_strategy().empty() ? "quick_restart" : "fixed");
-        m.parameters.add_subsolvers("core_or_no_lp"),
-            m.parameters.add_subsolvers("max_lp");
-
-      } else {
-        m.parameters.add_subsolvers("default_lp");
-        m.parameters.add_subsolvers(
-            m.proto.search_strategy().empty() ? "probing" : "fixed");
-        m.parameters.add_subsolvers("no_lp");
-        m.parameters.add_subsolvers("max_lp");
-        m.parameters.add_subsolvers("quick_restart");
+      m.parameters.set_use_rins_lns(false);
+      m.parameters.add_subsolvers("default_lp");
+      m.parameters.add_subsolvers("max_lp");
+      m.parameters.add_subsolvers("quick_restart");
+      m.parameters.add_subsolvers("core_or_no_lp");  // no_lp if no objective.
+      m.parameters.set_num_violation_ls(1);          // Off if no objective.
+      if (!m.proto.search_strategy().empty()) {
+        m.parameters.add_subsolvers("fixed");
       }
     }
   } else if (num_workers > 1 && num_workers < 8 && p.ortools_mode) {

ortools/sat/cp_model_solver.cc

@@ -2141,7 +2141,7 @@ void SolveCpModelParallel(SharedClasses* shared, Model* global_model) {
     }
     num_thread_available = std::max(num_thread_available, 0);
     // If we are in interleaved mode with one worker, num_thread_available is
-    // always negative. We force it to 1 so that we at least have a
+    // always zero. We force it to 1 so that we at least have a
     // feasibility_jump subsolver.
     if (params.interleave_search() && params.num_workers() == 1) {
       // TODO(user): the 1 should be a parameter.

ortools/sat/sat_runner.cc

@@ -171,23 +171,16 @@ void LogInPbCompetitionFormat(int num_variables, bool has_objective,
       final_response_callback);
 }
 
-void SetInterleavedWorkers(bool has_objective, SatParameters* parameters) {
+void SetInterleavedWorkers(SatParameters* parameters) {
   // Enable interleaved workers when num_workers is 1.
   if (parameters->num_workers() == 1) {
     parameters->set_interleave_search(true);
     parameters->set_use_rins_lns(false);
-    if (has_objective) {
-      parameters->add_subsolvers("default_lp");
-      parameters->add_subsolvers("quick_restart");
-      parameters->add_subsolvers("core_or_no_lp");
-      parameters->add_subsolvers("max_lp");
-      parameters->set_num_violation_ls(1);
-    } else {
-      parameters->add_subsolvers("default_lp");
-      parameters->add_subsolvers("no_lp");
-      parameters->add_subsolvers("max_lp");
-      parameters->add_subsolvers("quick_restart");
-    }
+    parameters->add_subsolvers("default_lp");
+    parameters->add_subsolvers("max_lp");
+    parameters->add_subsolvers("quick_restart");
+    parameters->add_subsolvers("core_or_no_lp");  // no_lp if no objective.
+    parameters->set_num_violation_ls(1);          // Off if no objective.
   }
 }
 
@@ -227,7 +220,7 @@ bool LoadProblem(const std::string& filename, absl::string_view hint_file,
                                parameters);
     }
     if (absl::GetFlag(FLAGS_force_interleave_search)) {
-      SetInterleavedWorkers(cp_model->has_objective(), parameters);
+      SetInterleavedWorkers(parameters);
     }
   } else if (absl::EndsWith(filename, ".cnf") ||
              absl::EndsWith(filename, ".cnf.xz") ||