#2201: added tempered criterion when ONLY load transfer is considered

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

@@ -1656,6 +1656,22 @@ auto TemperedLB::removeClusterToSend(
   );
 }
 
+double loadTransferCriterion(std::tuple<double, double, double> in_values){
+  // Compute maximum work of original arrangement
+  auto const before_w_src = std::get<0>(in_values);
+  auto const before_w_dst = std::get<1>(in_values);
+  auto const w_max_0 = std::max(before_w_src, before_w_dst);
+
+  // Compute maximum work of arrangement after load transfer
+  auto const src_l = std::get<2>(in_values);
+  auto const after_w_src = before_w_src - src_l;
+  auto const after_w_dst = before_w_dst + src_l;
+  auto const w_max_new = std::max(after_w_src, after_w_dst);
+
+  // Return criterion value
+  return w_max_0 - w_max_new;
+} // double loadTransferCriterion
+
 void TemperedLB::considerSubClustersAfterLock(MsgSharedPtr<LockedInfoMsg> msg) {
   is_swapping_ = true;
 
@@ -1666,18 +1682,22 @@ void TemperedLB::considerSubClustersAfterLock(MsgSharedPtr<LockedInfoMsg> msg) {
     auto const src_after_mem = current_memory_usage_;
     auto const try_after_mem = try_total_bytes + src_bytes;
 
+    // Check whether strict bounds on memory are satisfied
     if (src_after_mem > mem_thresh_ or try_after_mem > mem_thresh_) {
       return - std::numeric_limits<double>::infinity();
     }
 
+    // Compute maximum work of original arrangement
     auto const before_work_src = this_new_load_;
     auto const before_work_try = try_total_load;
     auto const w_max_0 = std::max(before_work_src, before_work_try);
 
+    // Compute maximum work of proposed new arrangement
     auto const after_work_src = this_new_load_ - src_load;
     auto const after_work_try = before_work_try + src_load;
     auto const w_max_new = std::max(after_work_src, after_work_try);
 
+    // Return criterion value
     return w_max_0 - w_max_new;
   };
 

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

@@ -218,6 +218,13 @@ struct TemperedLB : BaseLB {
    */
   void lockObtained(LockedInfoMsg* msg);
 
+  /**
+   * \brief Compute tempered criterion when only load transfer is considered
+   *
+   * \param[in] in_value contains: source work, destination work, transferred load
+   */
+  double loadTransferCriterion(std::tuple<double, double, double> in_values);
+
   /**
    * \brief Consider possible swaps with all the up-to-date info from a rank
    *