Changeset 7775 for branches/ScatterSearch/HeuristicLab.Algorithms.ScatterSearch/3.3/TravelingSalesman/TravelingSalesmanImprovementOperator.cs

Timestamp:

05/02/12 19:09:48 (12 years ago)

Author:

jkarder

Message:

#1331:

• added operators for TestFunctions problems
• added more path relinking operators for the TravelingSalesman and the Knapsack problem
• added 2-tier version of the SolutionPoolUpdateMethod
• added parameters and adjusted types
• added some exception handling
• adjusted event handling
• updated plugin dependencies
• minor code improvements

File:

• branches/ScatterSearch/HeuristicLab.Algorithms.ScatterSearch/3.3/TravelingSalesman/TravelingSalesmanImprovementOperator.cs (modified) (2 diffs)

branches/ScatterSearch/HeuristicLab.Algorithms.ScatterSearch/3.3/TravelingSalesman/TravelingSalesmanImprovementOperator.cs

@@ -138 +138 @@
 
       for (int i = 0; i < ImprovementAttempts.Value; i++) {
-        int a = Random.Next(currSol.Length - 1);
-        int b = Random.Next(currSol.Length - 1);
+        int a = Random.Next(currSol.Length);
+        int b = Random.Next(currSol.Length);
         Invert(currSol, a, b);
         currLength = TSPEuclideanPathEvaluator.Apply(Evaluator as TSPCoordinatesPathEvaluator, Coordinates, currSol);
         if (currLength < bestLength) {
           bestLength = currLength;
-          bestSol = (Permutation)currSol.Clone();
+          bestSol = currSol.Clone() as Permutation;
         }
         Invert(currSol, a, b);
@@ -155 +155 @@
 
     private void Invert(Permutation sol, int i, int j) {
-      if (i != j) {
-        for (int a = 0; a < Math.Abs(i - j) / 2; a++) {
-          int tmp = sol[(i + a) % sol.Length];
-          sol[(i + a) % sol.Length] = sol[(j - a + sol.Length) % sol.Length];
-          sol[(j - a + sol.Length) % sol.Length] = tmp;
-        }
-      }
+      if (i != j)
+        for (int a = 0; a < Math.Abs(i - j) / 2; a++)
+          if (sol[(i + a) % sol.Length] != sol[(j - a + sol.Length) % sol.Length]) {
+            // XOR swap
+            sol[(i + a) % sol.Length] ^= sol[(j - a + sol.Length) % sol.Length];
+            sol[(j - a + sol.Length) % sol.Length] ^= sol[(i + a) % sol.Length];
+            sol[(i + a) % sol.Length] ^= sol[(j - a + sol.Length) % sol.Length];
+          }
     }
   }