source: branches/2839_HiveProjectManagement/HeuristicLab.Encodings.PermutationEncoding/3.3/SimilarityCalculators/HammingSimilarityCalculator.cs @ 16057

Last change on this file since 16057 was 16057, checked in by jkarder, 16 months ago

#2839:

File size: 4.8 KB
Line 
1#region License Information
2/* HeuristicLab
3 * Copyright (C) 2002-2018 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.Optimization.Operators;
26using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
27
28namespace HeuristicLab.Encodings.PermutationEncoding {
29  [Item("Hamming Similarity Calculator for Permutation", "An operator that performs similarity calculation between two permutation-encoded solutions.")]
30  [StorableClass]
31  public sealed class HammingSimilarityCalculator : SingleObjectiveSolutionSimilarityCalculator {
32    protected override bool IsCommutative { get { return true; } }
33
34    [StorableConstructor]
35    private HammingSimilarityCalculator(bool deserializing) : base(deserializing) { }
36    private HammingSimilarityCalculator(HammingSimilarityCalculator original, Cloner cloner) : base(original, cloner) { }
37    public HammingSimilarityCalculator() : base() { }
38
39    public override IDeepCloneable Clone(Cloner cloner) {
40      return new HammingSimilarityCalculator(this, cloner);
41    }
42
43    public static double CalculateSimilarity(Permutation left, Permutation right) {
44      if (left == null || right == null)
45        throw new ArgumentException("Cannot calculate similarity because one or both of the provided solutions is null.");
46      if (left.PermutationType != right.PermutationType)
47        throw new ArgumentException("Cannot calculate similarity because the provided solutions have different permutation types.");
48      if (left.Length != right.Length)
49        throw new ArgumentException("Cannot calculate similarity because the provided solutions have different lengths.");
50      if (left.Length == 0)
51        throw new ArgumentException("Cannot calculate similarity because solutions are of length 0.");
52      if (ReferenceEquals(left, right)) return 1.0;
53
54      switch (left.PermutationType) {
55        case PermutationTypes.Absolute:
56          return CalculateAbsolute(left, right);
57        case PermutationTypes.RelativeDirected:
58          return CalculateRelativeDirected(left, right);
59        case PermutationTypes.RelativeUndirected:
60          return CalculateRelativeUndirected(left, right);
61        default:
62          throw new InvalidOperationException("unknown permutation type");
63      }
64    }
65
66    private static double CalculateAbsolute(Permutation left, Permutation right) {
67      double similarity = 0.0;
68      for (int i = 0; i < left.Length; i++)
69        if (left[i] == right[i]) similarity++;
70
71      return similarity / left.Length;
72    }
73
74    private static double CalculateRelativeDirected(Permutation left, Permutation right) {
75      int[] edgesR = CalculateEdgesVector(right);
76      int[] edgesL = CalculateEdgesVector(left);
77
78      double similarity = 0.0;
79      for (int i = 0; i < left.Length; i++) {
80        if (edgesL[i] == edgesR[i]) similarity++;
81      }
82
83      return similarity / left.Length;
84    }
85
86    private static double CalculateRelativeUndirected(Permutation left, Permutation right) {
87      int[] edgesR = CalculateEdgesVector(right);
88      int[] edgesL = CalculateEdgesVector(left);
89
90      double similarity = 0.0;
91      for (int i = 0; i < left.Length; i++) {
92        if ((edgesL[i] == edgesR[i]) || (edgesL[edgesR[i]] == i))
93          similarity++;
94      }
95
96      return similarity / left.Length;
97    }
98
99    private static int[] CalculateEdgesVector(Permutation permutation) {
100      // transform path representation into adjacency representation
101      int[] edgesVector = new int[permutation.Length];
102      for (int i = 0; i < permutation.Length - 1; i++)
103        edgesVector[permutation[i]] = permutation[i + 1];
104      edgesVector[permutation[permutation.Length - 1]] = permutation[0];
105      return edgesVector;
106    }
107
108    public override double CalculateSolutionSimilarity(IScope leftSolution, IScope rightSolution) {
109      var sol1 = leftSolution.Variables[SolutionVariableName].Value as Permutation;
110      var sol2 = rightSolution.Variables[SolutionVariableName].Value as Permutation;
111
112      return CalculateSimilarity(sol1, sol2);
113    }
114  }
115}
Note: See TracBrowser for help on using the repository browser.