geometric interpolation in cooling fm

kahypar · Jul 7, 2023 · 1dd9f74 · 1dd9f74
1 parent c51f377
commit 1dd9f74
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Showing 3 changed files with 12 additions and 2 deletions.
diff --git a/mt-kahypar/io/command_line_options.cpp b/mt-kahypar/io/command_line_options.cpp
@@ -570,6 +570,10 @@ namespace mt_kahypar {
              po::value<double>((initial_partitioning ? &context.initial_partitioning.refinement.fm.unconstrained_upper_bound_min :
                               &context.refinement.fm.unconstrained_upper_bound_min))->value_name("<double>")->default_value(0.0),
              "Cooling FM algorithm: Minimum (final) upper bound (default = 0 = equal to start).")
+            ((initial_partitioning ? "i-r-fm-cooling-geometric-interpolation" : "r-fm-cooling-geometric-interpolation"),
+             po::value<bool>((initial_partitioning ? &context.initial_partitioning.refinement.fm.geometric_interpolation :
+                              &context.refinement.fm.geometric_interpolation))->value_name("<bool>")->default_value(false),
+             "Cooling strategy: Use geometric instead of linear interpolation.")
             ((initial_partitioning ? "i-r-fm-activate-unconstrained-dynamically" : "r-fm-activate-unconstrained-dynamically"),
              po::value<bool>((initial_partitioning ? &context.initial_partitioning.refinement.fm.activate_unconstrained_dynamically :
                               &context.refinement.fm.activate_unconstrained_dynamically))->value_name("<bool>")->default_value(false),

diff --git a/mt-kahypar/partition/context.h b/mt-kahypar/partition/context.h
@@ -190,6 +190,7 @@ struct FMParameters {
   double imbalance_penalty_min = 0.2;
   double imbalance_penalty_max = 1.0;
   double unconstrained_upper_bound_min = 0.0;
+  bool geometric_interpolation = false;
 
   // unconstrained: dynamic enabling/disableing
   bool activate_unconstrained_dynamically = false;

diff --git a/mt-kahypar/partition/refinement/fm/strategies/cooling_strategy.h b/mt-kahypar/partition/refinement/fm/strategies/cooling_strategy.h
@@ -125,8 +125,13 @@ class CoolingStrategy: public IFMStrategy {
       if (round == 0) {
         return start;
       }
-      double summed = (n_rounds - round - 1) * start + round * end;
-      return summed / static_cast<double>(n_rounds - 1);
+      if (context.refinement.fm.geometric_interpolation) {
+        double factor = end / start;
+        return start * std::pow(factor, static_cast<double>(round) / static_cast<double>(n_rounds - 1));
+      } else {
+        double summed = (n_rounds - round - 1) * start + round * end;
+        return summed / static_cast<double>(n_rounds - 1);
+      }
     };
 
     if (round < n_rounds) {