Changeset 8322 for branches/ScatterSearch (trunk integration)/HeuristicLab.Problems.TravelingSalesman/3.3/PathRelinkers/TSPMultipleGuidesPathRelinker.cs

Timestamp:

07/25/12 10:14:58 (12 years ago)

Author:

jkarder

Message:

#1331:

• applied some of the changes suggested by ascheibe in comment:32:ticket:1331
• minor code improvements

File:

• branches/ScatterSearch (trunk integration)/HeuristicLab.Problems.TravelingSalesman/3.3/PathRelinkers/TSPMultipleGuidesPathRelinker.cs (modified) (1 diff)

branches/ScatterSearch (trunk integration)/HeuristicLab.Problems.TravelingSalesman/3.3/PathRelinkers/TSPMultipleGuidesPathRelinker.cs

@@ -85 +85 @@
         int bestCityIndex = (i + 1) % v1.Length;
         double currDistance = distances[v1[currCityIndex], v1[bestCityIndex]];
+        // check each guiding solution
         targets.ToList().ForEach(solution => {
-          var node = solution.Select((x, index) => new { Id = x, Index = index }).First(x => x.Id == v1[currCityIndex]);
+          // locate current city
+          var node = solution.Select((x, index) => new { Id = x, Index = index }).Single(x => x.Id == v1[currCityIndex]);
           int pred = solution[(node.Index - 1 + solution.Length) % solution.Length];
           int succ = solution[(node.Index + 1) % solution.Length];
+          // get distances to neighbors
           var results = new[] { pred, succ }.Select(x => new { Id = x, Distance = distances[x, node.Id] });
-          if (results.Any(x => x.Distance < currDistance)) {
-            var bestCity = results.OrderBy(x => x.Distance).First();
-            bestCityIndex = v1.Select((x, index) => new { Id = x, Index = index }).First(x => x.Id == bestCity.Id).Index;
+          var bestCity = results.Where(x => x.Distance < currDistance).OrderBy(x => x.Distance).FirstOrDefault();
+          if (bestCity != null) {
+            bestCityIndex = v1.Select((x, index) => new { Id = x, Index = index }).Single(x => x.Id == bestCity.Id).Index;
             currDistance = bestCity.Distance;
           }