[7789] | 1 | #region License Information
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| 2 | /* HeuristicLab
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[14312] | 3 | * Copyright (C) 2002-2016 Heuristic and Evolutionary Algorithms Laboratory (HEAL)
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[7789] | 4 | *
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| 5 | * This file is part of HeuristicLab.
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| 6 | *
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| 7 | * HeuristicLab is free software: you can redistribute it and/or modify
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| 8 | * it under the terms of the GNU General Public License as published by
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| 9 | * the Free Software Foundation, either version 3 of the License, or
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| 10 | * (at your option) any later version.
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| 11 | *
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| 12 | * HeuristicLab is distributed in the hope that it will be useful,
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| 13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of
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| 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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| 15 | * GNU General Public License for more details.
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| 16 | *
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| 17 | * You should have received a copy of the GNU General Public License
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| 18 | * along with HeuristicLab. If not, see <http://www.gnu.org/licenses/>.
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| 19 | */
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| 20 | #endregion
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| 21 |
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[8086] | 22 | using System;
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[7789] | 23 | using HeuristicLab.Common;
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| 24 | using HeuristicLab.Core;
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| 25 | using HeuristicLab.Encodings.PermutationEncoding;
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| 26 | using HeuristicLab.Optimization.Operators;
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| 27 |
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| 28 | namespace HeuristicLab.Problems.TravelingSalesman {
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| 29 | /// <summary>
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| 30 | /// An operator that performs similarity calculation between two traveling salesman solutions.
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| 31 | /// </summary>
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[8319] | 32 | /// <remarks>
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| 33 | /// The operator calculates the similarity based on the number of edges the two solutions have in common.
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| 34 | /// </remarks>
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[8327] | 35 | [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.")]
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[8319] | 36 | public sealed class TSPSimilarityCalculator : SingleObjectiveSolutionSimilarityCalculator {
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[12155] | 37 | protected override bool IsCommutative { get { return true; } }
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| 38 |
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[7789] | 39 | private TSPSimilarityCalculator(bool deserializing) : base(deserializing) { }
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| 40 | private TSPSimilarityCalculator(TSPSimilarityCalculator original, Cloner cloner) : base(original, cloner) { }
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| 41 | public TSPSimilarityCalculator() : base() { }
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| 42 |
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[8303] | 43 | public override IDeepCloneable Clone(Cloner cloner) {
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| 44 | return new TSPSimilarityCalculator(this, cloner);
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| 45 | }
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| 46 |
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[8086] | 47 | public static double CalculateSimilarity(Permutation left, Permutation right) {
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| 48 | if (left == null || right == null)
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| 49 | throw new ArgumentException("Cannot calculate similarity because one of the provided solutions or both are null.");
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[8319] | 50 | if (left.PermutationType != right.PermutationType)
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| 51 | throw new ArgumentException("Cannot calculate similarity because the provided solutions have different types.");
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| 52 | if (left.Length != right.Length)
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| 53 | throw new ArgumentException("Cannot calculate similarity because the provided solutions have different lengths.");
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[9030] | 54 | if (object.ReferenceEquals(left, right)) return 1.0;
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[7789] | 55 |
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[8319] | 56 | switch (left.PermutationType) {
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| 57 | case PermutationTypes.Absolute:
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| 58 | return CalculateAbsolute(left, right);
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| 59 | case PermutationTypes.RelativeDirected:
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| 60 | return CalculateRelativeDirected(left, right);
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| 61 | case PermutationTypes.RelativeUndirected:
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| 62 | return CalculateRelativeUndirected(left, right);
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| 63 | default:
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| 64 | throw new InvalidOperationException("unknown permutation type");
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| 65 | }
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| 66 | }
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| 67 |
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| 68 | private static double CalculateAbsolute(Permutation left, Permutation right) {
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| 69 | double similarity = 0.0;
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[8322] | 70 | for (int i = 0; i < left.Length; i++)
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| 71 | if (left[i] == right[i]) similarity++;
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| 72 |
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[8319] | 73 | return similarity / left.Length;
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| 74 | }
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| 75 |
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| 76 | private static double CalculateRelativeDirected(Permutation left, Permutation right) {
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[9443] | 77 | int[] edgesR = CalculateEdgesVector(right);
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| 78 | int[] edgesL = CalculateEdgesVector(left);
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[8322] | 79 |
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| 80 | double similarity = 0.0;
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[9443] | 81 | for (int i = 0; i < left.Length; i++) {
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| 82 | if (edgesL[i] == edgesR[i]) similarity++;
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| 83 | }
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[8322] | 84 |
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| 85 | return similarity / left.Length;
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[8319] | 86 | }
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| 87 |
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| 88 | private static double CalculateRelativeUndirected(Permutation left, Permutation right) {
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[9413] | 89 | int[] edgesR = CalculateEdgesVector(right);
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| 90 | int[] edgesL = CalculateEdgesVector(left);
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[7789] | 91 |
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| 92 | double similarity = 0.0;
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[8086] | 93 | for (int i = 0; i < left.Length; i++) {
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[9413] | 94 | if ((edgesL[i] == edgesR[i]) || (edgesL[edgesR[i]] == i))
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[7789] | 95 | similarity++;
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| 96 | }
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| 97 |
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[8086] | 98 | return similarity / left.Length;
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[7789] | 99 | }
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[8086] | 100 |
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[9413] | 101 | private static int[] CalculateEdgesVector(Permutation permutation) {
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| 102 | // transform path representation into adjacency representation
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| 103 | int[] edgesVector = new int[permutation.Length];
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| 104 | for (int i = 0; i < permutation.Length - 1; i++)
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| 105 | edgesVector[permutation[i]] = permutation[i + 1];
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| 106 | edgesVector[permutation[permutation.Length - 1]] = permutation[0];
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| 107 | return edgesVector;
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| 108 | }
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| 109 |
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[8319] | 110 | public override double CalculateSolutionSimilarity(IScope leftSolution, IScope rightSolution) {
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| 111 | var sol1 = leftSolution.Variables[SolutionVariableName].Value as Permutation;
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| 112 | var sol2 = rightSolution.Variables[SolutionVariableName].Value as Permutation;
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[8086] | 113 |
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| 114 | return CalculateSimilarity(sol1, sol2);
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| 115 | }
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[7789] | 116 | }
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| 117 | }
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