Cleaned up, and first of @mathgeekcoder's suggestions implemented

Author: jajhall

check/TestMipSolver.cpp

@@ -1037,7 +1037,7 @@ TEST_CASE("issue-2432", "[highs_test_mip_solver]") {
 }
 
 TEST_CASE("mip-race", "[highs_test_mip_solver]") {
-  const bool ci_test = false;
+  const bool ci_test = true;
   const std::string test_build_model = "fiball";
   const std::string model = ci_test ? "flugpl" : test_build_model;
   // "neos-3381206-awhea";
@@ -1048,6 +1048,7 @@ TEST_CASE("mip-race", "[highs_test_mip_solver]") {
   if (ci_test) h.setOptionValue("output_flag", dev_run);
   const HighsInt mip_race_concurrency = ci_test ? 2 : 4;
   h.setOptionValue("mip_race_concurrency", mip_race_concurrency);
+  h.setOptionValue("mip_race_read_solutions", true);
   REQUIRE(h.readModel(model_file) == HighsStatus::kOk);
   REQUIRE(h.run() == HighsStatus::kOk);
   REQUIRE(h.getModelStatus() == HighsModelStatus::kOptimal);

highs/mip/HighsMipSolver.h

@@ -33,6 +33,36 @@ struct MipRaceIncumbent {
                 std::vector<double>& solution_) const;
 };
 
+
+/*
+  struct MipRaceIncumbent {
+  std::atomic<HighsInt> start_write_incumbent = kMipRaceNoSolution;
+  std::atomic<HighsInt> finish_write_incumbent = kMipRaceNoSolution;
+  double objective = -kHighsInf;
+  std::vector<double> solution;
+  void clear();
+  void initialise(const HighsInt num_col);
+  void update(const double objective, const std::vector<double>& solution);
+  HighsInt read(const HighsInt last_incumbent_read, double& objective_,
+                std::vector<double>& solution_) const;
+
+  MipRaceIncumbent() = default;
+
+  MipRaceIncumbent(const MipRaceIncumbent& copy) {
+    start_write_incumbent = copy.start_write_incumbent.load();
+    finish_write_incumbent = copy.finish_write_incumbent.load();
+    objective = copy.objective;
+    solution = copy.solution;
+  }
+
+  MipRaceIncumbent(MipRaceIncumbent&& moving) {
+    start_write_incumbent = moving.start_write_incumbent.load();
+    finish_write_incumbent = moving.finish_write_incumbent.load();
+    objective = moving.objective;
+    solution = std::move(moving.solution);
+  }
+};
+*/
 struct MipRaceRecord {
   std::vector<MipRaceIncumbent> incumbent;
   void clear();

highs/mip/HighsMipSolverData.cpp

@@ -2923,13 +2923,20 @@ void MipRaceRecord::clear() { this->incumbent.clear(); }
 void MipRaceRecord::initialise(const HighsInt mip_race_concurrency,
                                const HighsInt num_col) {
   this->clear();
+  this->incumbent.resize(mip_race_concurrency);
+
+  for (HighsInt instance = 0; instance < mip_race_concurrency; instance++)
+    this->incumbent[instance].initialise(num_col);
+
+  /*
   MipRaceIncumbent incumbent_;
   incumbent_.initialise(num_col);
   // Loop from 1...
   for (HighsInt instance = 1; instance < mip_race_concurrency; instance++)
     this->incumbent.push_back(incumbent_);
   // ... and move incumbent_ to complete the vector of incumbents
   this->incumbent.push_back(std::move(incumbent_));
+  */
 }
 
 HighsInt MipRaceRecord::concurrency() const {