Free cookie consent management tool by TermsFeed Policy Generator

source: branches/PersistenceReintegration/HeuristicLab.Encodings.PermutationEncoding/3.3/SimilarityCalculators/HammingSimilarityCalculator.cs @ 14923

Last change on this file since 14923 was 14659, checked in by abeham, 8 years ago

#2730: Added similarity calculators and equality comparers

File size: 4.6 KB
Line 
1#region License Information
2/* HeuristicLab
3 * Copyright (C) 2002-2017 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;
26
27namespace HeuristicLab.Encodings.PermutationEncoding {
28  [Item("Hamming Similarity Calculator for Permutation", "An operator that performs similarity calculation between two permutation-encoded solutions.")]
29  public sealed class HammingSimilarityCalculator : SingleObjectiveSolutionSimilarityCalculator {
30    protected override bool IsCommutative { get { return true; } }
31
32    private HammingSimilarityCalculator(bool deserializing) : base(deserializing) { }
33    private HammingSimilarityCalculator(HammingSimilarityCalculator original, Cloner cloner) : base(original, cloner) { }
34    public HammingSimilarityCalculator() : base() { }
35
36    public override IDeepCloneable Clone(Cloner cloner) {
37      return new HammingSimilarityCalculator(this, cloner);
38    }
39
40    public static double CalculateSimilarity(Permutation left, Permutation right) {
41      if (left == null || right == null)
42        throw new ArgumentException("Cannot calculate similarity because one of the provided solutions or both are null.");
43      if (left.PermutationType != right.PermutationType)
44        throw new ArgumentException("Cannot calculate similarity because the provided solutions have different types.");
45      if (left.Length != right.Length)
46        throw new ArgumentException("Cannot calculate similarity because the provided solutions have different lengths.");
47      if (object.ReferenceEquals(left, right)) return 1.0;
48
49      switch (left.PermutationType) {
50        case PermutationTypes.Absolute:
51          return CalculateAbsolute(left, right);
52        case PermutationTypes.RelativeDirected:
53          return CalculateRelativeDirected(left, right);
54        case PermutationTypes.RelativeUndirected:
55          return CalculateRelativeUndirected(left, right);
56        default:
57          throw new InvalidOperationException("unknown permutation type");
58      }
59    }
60
61    private static double CalculateAbsolute(Permutation left, Permutation right) {
62      double similarity = 0.0;
63      for (int i = 0; i < left.Length; i++)
64        if (left[i] == right[i]) similarity++;
65
66      return similarity / left.Length;
67    }
68
69    private static double CalculateRelativeDirected(Permutation left, Permutation right) {
70      int[] edgesR = CalculateEdgesVector(right);
71      int[] edgesL = CalculateEdgesVector(left);
72
73      double similarity = 0.0;
74      for (int i = 0; i < left.Length; i++) {
75        if (edgesL[i] == edgesR[i]) similarity++;
76      }
77
78      return similarity / left.Length;
79    }
80
81    private static double CalculateRelativeUndirected(Permutation left, Permutation right) {
82      int[] edgesR = CalculateEdgesVector(right);
83      int[] edgesL = CalculateEdgesVector(left);
84
85      double similarity = 0.0;
86      for (int i = 0; i < left.Length; i++) {
87        if ((edgesL[i] == edgesR[i]) || (edgesL[edgesR[i]] == i))
88          similarity++;
89      }
90
91      return similarity / left.Length;
92    }
93
94    private static int[] CalculateEdgesVector(Permutation permutation) {
95      // transform path representation into adjacency representation
96      int[] edgesVector = new int[permutation.Length];
97      for (int i = 0; i < permutation.Length - 1; i++)
98        edgesVector[permutation[i]] = permutation[i + 1];
99      edgesVector[permutation[permutation.Length - 1]] = permutation[0];
100      return edgesVector;
101    }
102
103    public override double CalculateSolutionSimilarity(IScope leftSolution, IScope rightSolution) {
104      var sol1 = leftSolution.Variables[SolutionVariableName].Value as Permutation;
105      var sol2 = rightSolution.Variables[SolutionVariableName].Value as Permutation;
106
107      return CalculateSimilarity(sol1, sol2);
108    }
109  }
110}
Note: See TracBrowser for help on using the repository browser.