[5930] | 1 | #region License Information
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| 2 | /* HeuristicLab
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[11594] | 3 | * Copyright (C) 2002-2014 Heuristic and Evolutionary Algorithms Laboratory (HEAL)
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[5930] | 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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| 22 | using System;
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| 23 | using HeuristicLab.Common;
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| 24 | using HeuristicLab.Core;
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| 25 | using HeuristicLab.Data;
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| 26 | using HeuristicLab.Encodings.PermutationEncoding;
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| 27 | using HeuristicLab.Parameters;
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| 28 | using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
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| 29 |
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| 30 | namespace HeuristicLab.Problems.QuadraticAssignment {
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| 31 | [Item("QAPSwap2MoveEvaluator", "Evaluated a swap-2 move on a QAP solution.")]
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| 32 | [StorableClass]
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| 33 | public class QAPSwap2MoveEvaluator : QAPMoveEvaluator, IPermutationSwap2MoveOperator {
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| 34 | public ILookupParameter<Swap2Move> Swap2MoveParameter {
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| 35 | get { return (ILookupParameter<Swap2Move>)Parameters["Swap2Move"]; }
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| 36 | }
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| 37 |
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| 38 | [StorableConstructor]
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| 39 | protected QAPSwap2MoveEvaluator(bool deserializing) : base(deserializing) { }
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| 40 | protected QAPSwap2MoveEvaluator(QAPSwap2MoveEvaluator original, Cloner cloner)
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| 41 | : base(original, cloner) {
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| 42 | }
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| 43 | public QAPSwap2MoveEvaluator() {
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| 44 | Parameters.Add(new LookupParameter<Swap2Move>("Swap2Move", "The move to evaluate."));
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| 45 | }
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| 46 |
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| 47 | public override IDeepCloneable Clone(Cloner cloner) {
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| 48 | return new QAPSwap2MoveEvaluator(this, cloner);
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| 49 | }
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| 50 |
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[6628] | 51 | /// <summary>
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| 52 | /// Calculates the quality of the move <paramref name="move"/> by evaluating the changes.
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| 53 | /// The runtime complexity of this method is O(N) with N being the size of the permutation.
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| 54 | /// </summary>
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| 55 | /// <param name="assignment">The current permutation.</param>
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| 56 | /// <param name="move">The move that is to be evaluated if it was applied to the current permutation.</param>
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| 57 | /// <param name="weights">The weights matrix.</param>
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| 58 | /// <param name="distances">The distances matrix.</param>
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| 59 | /// <returns>The relative change in quality if <paramref name="move"/> was applied to <paramref name="assignment"/>.</returns>
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[5930] | 60 | public static double Apply(Permutation assignment, Swap2Move move, DoubleMatrix weights, DoubleMatrix distances) {
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| 61 | if (move.Index1 == move.Index2) return 0;
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| 62 | double moveQuality = 0;
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| 63 | int fac1 = move.Index1, fac2 = move.Index2;
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| 64 | int loc1 = assignment[fac1], loc2 = assignment[fac2];
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| 65 |
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| 66 | for (int j = 0; j < assignment.Length; j++) {
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| 67 | if (j == fac1) {
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| 68 | moveQuality += weights[fac1, fac1] * (distances[loc2, loc2] - distances[loc1, loc1]);
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| 69 | moveQuality += weights[fac1, fac2] * (distances[loc2, loc1] - distances[loc1, loc2]);
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| 70 | } else if (j == fac2) {
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| 71 | moveQuality += weights[fac2, fac2] * (distances[loc1, loc1] - distances[loc2, loc2]);
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| 72 | moveQuality += weights[fac2, fac1] * (distances[loc1, loc2] - distances[loc2, loc1]);
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| 73 | } else {
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| 74 | int locJ = assignment[j];
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| 75 | moveQuality += weights[fac1, j] * (distances[loc2, locJ] - distances[loc1, locJ]);
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| 76 | moveQuality += weights[j, fac1] * (distances[locJ, loc2] - distances[locJ, loc1]);
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| 77 | moveQuality += weights[fac2, j] * (distances[loc1, locJ] - distances[loc2, locJ]);
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| 78 | moveQuality += weights[j, fac2] * (distances[locJ, loc1] - distances[locJ, loc2]);
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| 79 | }
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| 80 | }
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| 81 | return moveQuality;
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| 82 | }
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| 83 |
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[6628] | 84 | /// <summary>
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| 85 | /// Is able to compute the move qualities faster O(1) in some cases if it knows the quality of
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| 86 | /// performing the move <paramref name="move"/> previously. In other cases it performs a
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| 87 | /// standard move quality calculation with runtime complexity O(N).
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| 88 | /// </summary>
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| 89 | /// <remarks>
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| 90 | /// The number of cases that the calculation can be performed faster grows with N^2
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| 91 | /// while the number of cases which require a larger recalculation grows linearly with N.
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| 92 | /// Larger problem instances thus benefit from this faster method to a larger degree.
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| 93 | /// </remarks>
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| 94 | /// <param name="assignment">The current permutation.</param>
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| 95 | /// <param name="move">The current move that is to be evaluated.</param>
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| 96 | /// <param name="previousQuality">The quality of that move as evaluated for the previous permutation.</param>
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| 97 | /// <param name="weights">The weigths matrix.</param>
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| 98 | /// <param name="distances">The distances matrix.</param>
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| 99 | /// <param name="lastMove">The move that was applied to transform the permutation from the previous to the current one.</param>
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| 100 | /// <returns>The relative change in quality if <paramref name="move"/> was applied to <paramref name="assignment"/>.</returns>
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| 101 | public static double Apply(Permutation assignment, Swap2Move move, double previousQuality,
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| 102 | DoubleMatrix weights, DoubleMatrix distances, Swap2Move lastMove) {
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| 103 | bool overlapsLastMove = move.Index1 == lastMove.Index1
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| 104 | || move.Index2 == lastMove.Index1
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| 105 | || move.Index1 == lastMove.Index2
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| 106 | || move.Index2 == lastMove.Index2;
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| 107 |
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| 108 | if (!overlapsLastMove) {
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| 109 | int r = lastMove.Index1, u = move.Index1, s = lastMove.Index2, v = move.Index2;
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| 110 | int pR = assignment[lastMove.Index1], pU = assignment[move.Index1], pS = assignment[lastMove.Index2], pV = assignment[move.Index2];
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| 111 |
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| 112 | return previousQuality
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| 113 | + (weights[r, u] - weights[r, v] + weights[s, v] - weights[s, u])
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| 114 | * (distances[pS, pU] - distances[pS, pV] + distances[pR, pV] - distances[pR, pU])
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| 115 | + (weights[u, r] - weights[v, r] + weights[v, s] - weights[u, s])
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| 116 | * (distances[pU, pS] - distances[pV, pS] + distances[pV, pR] - distances[pU, pR]);
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| 117 | } else {
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| 118 | return Apply(assignment, move, weights, distances);
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| 119 | }
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| 120 | }
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| 121 |
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[5930] | 122 | public override IOperation Apply() {
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| 123 | Swap2Move move = Swap2MoveParameter.ActualValue;
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| 124 | if (move == null) throw new InvalidOperationException("Swap-2 move is not found.");
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| 125 | Permutation assignment = PermutationParameter.ActualValue;
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| 126 | DoubleMatrix distances = DistancesParameter.ActualValue;
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| 127 | DoubleMatrix weights = WeightsParameter.ActualValue;
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| 128 |
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| 129 | double moveQuality = QualityParameter.ActualValue.Value;
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| 130 | moveQuality += Apply(assignment, move, weights, distances);
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| 131 | MoveQualityParameter.ActualValue = new DoubleValue(moveQuality);
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| 132 | return base.Apply();
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| 133 | }
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| 134 | }
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| 135 | }
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