mpl2: comment

Signed-off-by: Arthur Koucher <arthurckoucher@gmail.com>

src/mpl2/src/SimulatedAnnealingCore.cpp

@@ -608,8 +608,9 @@ void SimulatedAnnealingCore<T>::attemptCentralization(const float pre_cost)
     return;
   }
 
-  // In order to revert the centralization, we cache the current
-  // location of the clusters to avoid floating-point evilness.
+  // In order to revert the centralization, we cache the current location
+  // of the clusters to avoid floating-point evilness when creating the
+  // x,y grid to fill the dead space by expanding mixed clusters.
   std::vector<std::pair<float, float>> clusters_locations;
   for (int& id : pos_seq_) {
     clusters_locations.emplace_back(macros_[id].getX(), macros_[id].getY());