#1279: gossiplb: order objects by object id

src/vt/vrt/collection/balance/gossiplb/gossiplb.cc

@@ -122,7 +122,7 @@ void GossipLB::runLB() {
 }
 
 void GossipLB::doLBStages(TimeType start_imb) {
-  std::unordered_map<ObjIDType, TimeType> best_objs;
+  decltype(this->cur_objs_) best_objs;
   LoadType best_load = 0;
   TimeType best_imb = start_imb+1;
   uint16_t best_trial = 0;
@@ -149,7 +149,10 @@ void GossipLB::doLBStages(TimeType start_imb) {
 
       if (first_iter) {
         // Copy this node's object assignments to a local, mutable copy
-        cur_objs_ = *load_data;
+        cur_objs_.clear();
+        for (auto obj : *load_data) {
+          cur_objs_[obj.first] = obj.second;
+        }
         this_new_load_ = this_load;
       } else {
         // Clear out data structures from previous iteration

src/vt/vrt/collection/balance/gossiplb/gossiplb.h

@@ -130,7 +130,7 @@ struct GossipLB : BaseLB {
   std::unordered_set<NodeType> selected_            = {};
   std::unordered_set<NodeType> underloaded_         = {};
   std::unordered_set<NodeType> new_underloaded_     = {};
-  std::unordered_map<ObjIDType, TimeType> cur_objs_ = {};
+  std::map<ObjIDType, TimeType> cur_objs_           = {};
   LoadType this_new_load_                           = 0.0;
   TimeType new_imbalance_                           = 0.0;
   CriterionEnum criterion_                          = CriterionEnum::ModifiedGrapevine;