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source: branches/PersistenceOverhaul/HeuristicLab.Problems.TravelingSalesman/3.3/SimilarityCalculators/TSPSimilarityCalculator.cs @ 14713

Last change on this file since 14713 was 14713, checked in by gkronber, 7 years ago

#2520 work in progress to support loading/saving of all samples

File size: 5.1 KB
Line 
1#region License Information
2/* HeuristicLab
3 * Copyright (C) 2002-2015 Heuristic and Evolutionary Algorithms Laboratory (HEAL)
4 *
5 * This file is part of HeuristicLab.
6 *
7 * HeuristicLab is free software: you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation, either version 3 of the License, or
10 * (at your option) any later version.
11 *
12 * HeuristicLab is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with HeuristicLab. If not, see <http://www.gnu.org/licenses/>.
19 */
20#endregion
21
22using System;
23using HeuristicLab.Common;
24using HeuristicLab.Core;
25using HeuristicLab.Encodings.PermutationEncoding;
26using HeuristicLab.Optimization.Operators;
27using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
28
29namespace HeuristicLab.Problems.TravelingSalesman {
30  /// <summary>
31  /// An operator that performs similarity calculation between two traveling salesman solutions.
32  /// </summary>
33  /// <remarks>
34  /// The operator calculates the similarity based on the number of edges the two solutions have in common.
35  /// </remarks>
36  [StorableType("D5AD7A09-5738-4F14-AB3C-4943C32FACC6")]   
37  [Item("TSPSimilarityCalculator", "An operator that performs similarity calculation between two traveling salesman solutions. The operator calculates the similarity based on the number of edges the two solutions have in common.")]
38  public sealed class TSPSimilarityCalculator : SingleObjectiveSolutionSimilarityCalculator {
39    protected override bool IsCommutative { get { return true; } }
40
41    private TSPSimilarityCalculator(bool deserializing) : base(deserializing) { }
42    private TSPSimilarityCalculator(TSPSimilarityCalculator original, Cloner cloner) : base(original, cloner) { }
43    public TSPSimilarityCalculator() : base() { }
44
45    public override IDeepCloneable Clone(Cloner cloner) {
46      return new TSPSimilarityCalculator(this, cloner);
47    }
48
49    public static double CalculateSimilarity(Permutation left, Permutation right) {
50      if (left == null || right == null)
51        throw new ArgumentException("Cannot calculate similarity because one of the provided solutions or both are null.");
52      if (left.PermutationType != right.PermutationType)
53        throw new ArgumentException("Cannot calculate similarity because the provided solutions have different types.");
54      if (left.Length != right.Length)
55        throw new ArgumentException("Cannot calculate similarity because the provided solutions have different lengths.");
56      if (object.ReferenceEquals(left, right)) return 1.0;
57
58      switch (left.PermutationType) {
59        case PermutationTypes.Absolute:
60          return CalculateAbsolute(left, right);
61        case PermutationTypes.RelativeDirected:
62          return CalculateRelativeDirected(left, right);
63        case PermutationTypes.RelativeUndirected:
64          return CalculateRelativeUndirected(left, right);
65        default:
66          throw new InvalidOperationException("unknown permutation type");
67      }
68    }
69
70    private static double CalculateAbsolute(Permutation left, Permutation right) {
71      double similarity = 0.0;
72      for (int i = 0; i < left.Length; i++)
73        if (left[i] == right[i]) similarity++;
74
75      return similarity / left.Length;
76    }
77
78    private static double CalculateRelativeDirected(Permutation left, Permutation right) {
79      int[] edgesR = CalculateEdgesVector(right);
80      int[] edgesL = CalculateEdgesVector(left);
81
82      double similarity = 0.0;
83      for (int i = 0; i < left.Length; i++) {
84        if (edgesL[i] == edgesR[i]) similarity++;
85      }
86
87      return similarity / left.Length;
88    }
89
90    private static double CalculateRelativeUndirected(Permutation left, Permutation right) {
91      int[] edgesR = CalculateEdgesVector(right);
92      int[] edgesL = CalculateEdgesVector(left);
93
94      double similarity = 0.0;
95      for (int i = 0; i < left.Length; i++) {
96        if ((edgesL[i] == edgesR[i]) || (edgesL[edgesR[i]] == i))
97          similarity++;
98      }
99
100      return similarity / left.Length;
101    }
102
103    private static int[] CalculateEdgesVector(Permutation permutation) {
104      // transform path representation into adjacency representation
105      int[] edgesVector = new int[permutation.Length];
106      for (int i = 0; i < permutation.Length - 1; i++)
107        edgesVector[permutation[i]] = permutation[i + 1];
108      edgesVector[permutation[permutation.Length - 1]] = permutation[0];
109      return edgesVector;
110    }
111
112    public override double CalculateSolutionSimilarity(IScope leftSolution, IScope rightSolution) {
113      var sol1 = leftSolution.Variables[SolutionVariableName].Value as Permutation;
114      var sol2 = rightSolution.Variables[SolutionVariableName].Value as Permutation;
115
116      return CalculateSimilarity(sol1, sol2);
117    }
118  }
119}
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