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source: branches/2520_PersistenceReintegration/HeuristicLab.Problems.TravelingSalesman/3.3/SimilarityCalculators/TSPSimilarityCalculator.cs @ 16453

Last change on this file since 16453 was 16453, checked in by jkarder, 5 years ago

#2520: updated year of copyrights

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1#region License Information
2/* HeuristicLab
3 * Copyright (C) 2002-2019 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.PluginInfrastructure;
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  [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.")]
37  [Obsolete("This operator is similar to the Hamming similarity calculator in the Encodings.PermutationEncoding namespace")]
38  [NonDiscoverableType]
39  internal sealed class TSPSimilarityCalculator : SingleObjectiveSolutionSimilarityCalculator {
40    protected override bool IsCommutative { get { return true; } }
41
42    private TSPSimilarityCalculator(bool deserializing) : base(deserializing) { }
43    private TSPSimilarityCalculator(TSPSimilarityCalculator original, Cloner cloner) : base(original, cloner) { }
44    public TSPSimilarityCalculator() : base() { }
45
46    public override IDeepCloneable Clone(Cloner cloner) {
47      return new TSPSimilarityCalculator(this, cloner);
48    }
49
50    public static double CalculateSimilarity(Permutation left, Permutation right) {
51      if (left == null || right == null)
52        throw new ArgumentException("Cannot calculate similarity because one of the provided solutions or both are null.");
53      if (left.PermutationType != right.PermutationType)
54        throw new ArgumentException("Cannot calculate similarity because the provided solutions have different types.");
55      if (left.Length != right.Length)
56        throw new ArgumentException("Cannot calculate similarity because the provided solutions have different lengths.");
57      if (object.ReferenceEquals(left, right)) return 1.0;
58
59      switch (left.PermutationType) {
60        case PermutationTypes.Absolute:
61          return CalculateAbsolute(left, right);
62        case PermutationTypes.RelativeDirected:
63          return CalculateRelativeDirected(left, right);
64        case PermutationTypes.RelativeUndirected:
65          return CalculateRelativeUndirected(left, right);
66        default:
67          throw new InvalidOperationException("unknown permutation type");
68      }
69    }
70
71    private static double CalculateAbsolute(Permutation left, Permutation right) {
72      double similarity = 0.0;
73      for (int i = 0; i < left.Length; i++)
74        if (left[i] == right[i]) similarity++;
75
76      return similarity / left.Length;
77    }
78
79    private static double CalculateRelativeDirected(Permutation left, Permutation right) {
80      int[] edgesR = CalculateEdgesVector(right);
81      int[] edgesL = CalculateEdgesVector(left);
82
83      double similarity = 0.0;
84      for (int i = 0; i < left.Length; i++) {
85        if (edgesL[i] == edgesR[i]) similarity++;
86      }
87
88      return similarity / left.Length;
89    }
90
91    private static double CalculateRelativeUndirected(Permutation left, Permutation right) {
92      int[] edgesR = CalculateEdgesVector(right);
93      int[] edgesL = CalculateEdgesVector(left);
94
95      double similarity = 0.0;
96      for (int i = 0; i < left.Length; i++) {
97        if ((edgesL[i] == edgesR[i]) || (edgesL[edgesR[i]] == i))
98          similarity++;
99      }
100
101      return similarity / left.Length;
102    }
103
104    private static int[] CalculateEdgesVector(Permutation permutation) {
105      // transform path representation into adjacency representation
106      int[] edgesVector = new int[permutation.Length];
107      for (int i = 0; i < permutation.Length - 1; i++)
108        edgesVector[permutation[i]] = permutation[i + 1];
109      edgesVector[permutation[permutation.Length - 1]] = permutation[0];
110      return edgesVector;
111    }
112
113    public override double CalculateSolutionSimilarity(IScope leftSolution, IScope rightSolution) {
114      var sol1 = leftSolution.Variables[SolutionVariableName].Value as Permutation;
115      var sol2 = rightSolution.Variables[SolutionVariableName].Value as Permutation;
116
117      return CalculateSimilarity(sol1, sol2);
118    }
119  }
120}
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