Short run fine tuning (#444)

This PR incorporates earlier logging of feasible solutions and reduces some excessive time limits in the initial solving phase to improve results on short timeframes.

Authors:
  - Alice Boucher (https://github.com/aliceb-nv)

Approvers:
  - Rajesh Gandham (https://github.com/rg20)

URL: #444

Author: aliceb-nv

cpp/src/mip/diversity/diversity_config.hpp

@@ -21,9 +21,9 @@ namespace cuopt::linear_programming::detail {
 
 struct diversity_config_t {
   double time_ratio_on_init_lp              = 0.1;
-  double max_time_on_lp                     = 30;
+  double max_time_on_lp                     = 15.0;
   double time_ratio_of_probing_cache        = 0.04;
-  double max_time_on_probing                = 60;
+  double max_time_on_probing                = 15.0;
   size_t max_iterations_without_improvement = 15;
   int max_var_diff                          = 256;
   size_t max_solutions                      = 32;

cpp/src/mip/diversity/population.cu

@@ -172,6 +172,10 @@ void population_t<i_t, f_t>::add_external_solution(const std::vector<f_t>& solut
                   solution_origin_to_string(origin),
                   external_solution_queue.size(),
                   problem_ptr->get_user_obj_from_solver_obj(objective));
+  if (objective < best_feasible_objective) {
+    CUOPT_LOG_DEBUG("Found new best solution %g in external queue",
+                    problem_ptr->get_user_obj_from_solver_obj(objective));
+  }
   if (external_solution_queue.size() >= 5) { early_exit_primal_generation = true; }
 }
 

cpp/src/mip/local_search/local_search.cu

@@ -176,9 +176,6 @@ void local_search_t<i_t, f_t>::start_cpufj_scratch_threads(population_t<i_t, f_t
     counter++;
   };
 
-  // default weights
-  cudaDeviceSynchronize();
-
   for (auto& cpu_fj : scratch_cpu_fj) {
     cpu_fj.start_cpu_solver();
   }