Changeset 6909 for branches/VRP/HeuristicLab.Problems.VehicleRouting/3.4/Encodings/Potvin/Moves/PickupDelivery/PDExchange/PotvinPDExchangeSingleMoveGenerator.cs

Timestamp:

10/12/11 15:45:48 (13 years ago)

Author:

svonolfe

Message:

Fixed more isses that occured in dynamic instances (#1177)

File:

• branches/VRP/HeuristicLab.Problems.VehicleRouting/3.4/Encodings/Potvin/Moves/PickupDelivery/PDExchange/PotvinPDExchangeSingleMoveGenerator.cs (modified) (1 diff)

branches/VRP/HeuristicLab.Problems.VehicleRouting/3.4/Encodings/Potvin/Moves/PickupDelivery/PDExchange/PotvinPDExchangeSingleMoveGenerator.cs

@@ -66 +66 @@
       }
 
-      PotvinPDExchangeMove move = null;
-      while (cities.Count > 0 && move == null) {
-        int city = cities[rand.Next(cities.Count)];
-        Tour oldTour = individual.Tours.Find(t => t.Stops.Contains(city));
-        int oldTourIndex = individual.Tours.IndexOf(oldTour);
+      if (cities.Count > 1 && individual.Tours.Count > 1) {
+        PotvinPDExchangeMove move = null;
+        while (cities.Count > 1 && move == null) {
+          int city = cities[rand.Next(cities.Count)];
+          Tour oldTour = individual.Tours.Find(t => t.Stops.Contains(city));
+          int oldTourIndex = individual.Tours.IndexOf(oldTour);
 
-        int max = individual.Tours.Count;
-        if (individual.Tours.Count < problemInstance.Vehicles.Value)
-          max = max - 1;
+          int max = individual.Tours.Count;
+          if (individual.Tours.Count < problemInstance.Vehicles.Value)
+            max = max - 1;
 
-        int newTourIndex = rand.Next(max);
-        if (newTourIndex >= oldTourIndex)
-          newTourIndex++;
+          int newTourIndex = rand.Next(max);
+          if (newTourIndex >= oldTourIndex)
+            newTourIndex++;
 
-        Tour newTour = individual.Tours[newTourIndex];
-        List<int> tourCities = new List<int>();
-        foreach (int stop in newTour.Stops) {
-          if (pdp == null ||
-            (pdp.GetDemand(stop) >= 0 &&
-            pdp.GetPickupDeliveryLocation(stop) != pdp.GetPickupDeliveryLocation(city) &&
-            pdp.GetPickupDeliveryLocation(stop) != city &&
-            pdp.GetPickupDeliveryLocation(city) != stop))
-            tourCities.Add(stop);
+          Tour newTour = individual.Tours[newTourIndex];
+          List<int> tourCities = new List<int>();
+          foreach (int stop in newTour.Stops) {
+            if (pdp == null ||
+              (pdp.GetDemand(stop) >= 0 &&
+              pdp.GetPickupDeliveryLocation(stop) != pdp.GetPickupDeliveryLocation(city) &&
+              pdp.GetPickupDeliveryLocation(stop) != city &&
+              pdp.GetPickupDeliveryLocation(city) != stop))
+              tourCities.Add(stop);
+          }
+
+          if (tourCities.Count > 0) {
+            int replaced = tourCities[rand.Next(tourCities.Count)];
+            move = new PotvinPDExchangeMove(city, oldTourIndex, newTourIndex, replaced, individual);
+          }
         }
 
-        if (tourCities.Count > 0) {
-          int replaced = tourCities[rand.Next(tourCities.Count)];
-          move = new PotvinPDExchangeMove(city, oldTourIndex, newTourIndex, replaced, individual);
-        }
-      }
-
-      return move;
+        return move;
+      } else {
+        return null;
+      }             
     }