1 | #region License Information
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2 | /* HeuristicLab
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3 | * Copyright (C) 2002-2014 Heuristic and Evolutionary Algorithms Laboratory (HEAL)
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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.Collections.Generic;
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23 | using System.Linq;
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24 | using HeuristicLab.Common;
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25 | using HeuristicLab.Core;
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26 | using HeuristicLab.Data;
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27 | using HeuristicLab.Encodings.IntegerVectorEncoding;
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28 | using HeuristicLab.Operators;
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29 | using HeuristicLab.Optimization;
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30 | using HeuristicLab.Parameters;
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31 | using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
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32 |
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33 | namespace HeuristicLab.Problems.Orienteering {
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34 | [Item("OrienteeringShakingOperator", @"The used neighborhood operator is based on a two point exchange move. A move in
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35 | the k-th neighborhood consists of removing k consecutive vertices from the tour, starting
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36 | at a randomly selected position. Afterwards, a sorted list of all vertices not yet included
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37 | in the current tour is built. The vertices are sorted in descending order with respect to the
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38 | objective value increase using the current weights. Out of the first three entries with the
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39 | highest ranking in this list, one randomly selected vertex is reinserted into the current tour
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40 | at the same position as the removed vertices. This way, l new vertices are inserted into the
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41 | tour. The largest neighborhood is a complete exchange of all vertices on the tour.
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42 | The shaking procedure does not guarantee that the new tour does not exceed the cost
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43 | limit Tmax. Therefore, in a repair step, a sorted list of all vertices in the tour is created. The
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44 | vertices are sorted in descending order with respect to costs saved when removing the vertex
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45 | from the tour. Vertices are removed as long as the cost limit is violated.
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46 | (Schilde et. al. 2009)")]
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47 | [StorableClass]
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48 | public class OrienteeringShakingOperator : SingleSuccessorOperator, IMultiNeighborhoodShakingOperator, IStochasticOperator {
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49 |
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50 | #region Shaking Parameter Properties
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51 | public IValueLookupParameter<IntValue> CurrentNeighborhoodIndexParameter {
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52 | get { return (IValueLookupParameter<IntValue>)Parameters["CurrentNeighborhoodIndex"]; }
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53 | }
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54 | public ILookupParameter<IntValue> NeighborhoodCountParameter {
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55 | get { return (ILookupParameter<IntValue>)Parameters["NeighborhoodCount"]; }
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56 | }
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57 | #endregion
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58 |
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59 | #region Parameter Properties
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60 | public ILookupParameter<IntegerVector> IntegerVectorParameter {
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61 | get { return (ILookupParameter<IntegerVector>)Parameters["IntegerVector"]; }
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62 | }
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63 | public ILookupParameter<DoubleValue> MaximumDistanceParameter {
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64 | get { return (ILookupParameter<DoubleValue>)Parameters["MaximumDistance"]; }
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65 | }
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66 | public ILookupParameter<IntValue> StartingPointParameter {
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67 | get { return (ILookupParameter<IntValue>)Parameters["StartingPoint"]; }
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68 | }
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69 | public ILookupParameter<IntValue> TerminusPointParameter {
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70 | get { return (ILookupParameter<IntValue>)Parameters["TerminusPoint"]; }
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71 | }
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72 | public ILookupParameter<DistanceMatrix> DistanceMatrixParameter {
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73 | get { return (ILookupParameter<DistanceMatrix>)Parameters["DistanceMatrix"]; }
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74 | }
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75 | public ILookupParameter<DoubleArray> ScoresParameter {
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76 | get { return (ILookupParameter<DoubleArray>)Parameters["Scores"]; }
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77 | }
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78 | public ILookupParameter<DoubleValue> FixedPenaltyParameter {
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79 | get { return (ILookupParameter<DoubleValue>)Parameters["FixedPenalty"]; }
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80 | }
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81 |
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82 | public ILookupParameter<IRandom> RandomParameter {
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83 | get { return (ILookupParameter<IRandom>)Parameters["Random"]; }
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84 | }
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85 | #endregion
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86 |
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87 | [StorableConstructor]
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88 | private OrienteeringShakingOperator(bool deserializing) : base(deserializing) { }
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89 | private OrienteeringShakingOperator(OrienteeringShakingOperator original, Cloner cloner)
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90 | : base(original, cloner) {
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91 | }
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92 | public OrienteeringShakingOperator()
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93 | : base() {
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94 | Parameters.Add(new ValueLookupParameter<IntValue>("CurrentNeighborhoodIndex", "The index of the operator that should be applied (k)."));
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95 | Parameters.Add(new LookupParameter<IntValue>("NeighborhoodCount", "The number of operators that are available."));
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96 |
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97 | Parameters.Add(new LookupParameter<IntegerVector>("IntegerVector", "The Orienteering Solution given in path representation."));
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98 | Parameters.Add(new LookupParameter<DoubleValue>("MaximumDistance", "The maximum distance constraint for a Orienteering solution."));
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99 | Parameters.Add(new LookupParameter<IntValue>("StartingPoint", "Index of the starting point."));
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100 | Parameters.Add(new LookupParameter<IntValue>("TerminusPoint", "Index of the ending point."));
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101 | Parameters.Add(new LookupParameter<DistanceMatrix>("DistanceMatrix", "The matrix which contains the distances between the points."));
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102 | Parameters.Add(new LookupParameter<DoubleArray>("Scores", "The scores of the points."));
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103 | Parameters.Add(new LookupParameter<DoubleValue>("FixedPenalty", "The penalty for each visited vertex."));
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104 |
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105 | Parameters.Add(new LookupParameter<IRandom>("Random", "The random number generator that will be used."));
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106 | }
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107 |
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108 | public override IDeepCloneable Clone(Cloner cloner) {
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109 | return new OrienteeringShakingOperator(this, cloner);
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110 | }
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111 |
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112 | public override IOperation Apply() {
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113 | var initialTour = IntegerVectorParameter.ActualValue;
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114 | var distances = DistanceMatrixParameter.ActualValue;
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115 | var scores = ScoresParameter.ActualValue;
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116 | var startingPoint = StartingPointParameter.ActualValue.Value;
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117 | var terminusPoint = TerminusPointParameter.ActualValue.Value;
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118 | var fixedPenalty = FixedPenaltyParameter.ActualValue.Value;
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119 | double maxDistance = MaximumDistanceParameter.ActualValue.Value;
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120 | int numPoints = scores.Length;
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121 |
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122 | if (NeighborhoodCountParameter.ActualValue == null)
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123 | NeighborhoodCountParameter.ActualValue = new IntValue(initialTour.Length);
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124 | else NeighborhoodCountParameter.ActualValue.Value = initialTour.Length;
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125 |
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126 | var random = RandomParameter.ActualValue;
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127 |
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128 | if (initialTour.Length > 2) {
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129 | // Limit the neighborhood to the tour length
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130 | int maxNeighborhood = CurrentNeighborhoodIndexParameter.ActualValue.Value + 1;
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131 | int limit = initialTour.Length - 2; // neighborhood limit within [0, changable tour length - 1)
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132 | int neighborhood = random.Next((limit > maxNeighborhood) ? maxNeighborhood : limit) + 1;
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133 |
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134 | // Find all points that are not yet included in the tour and are
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135 | // within the maximum distance allowed (ellipse)
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136 | // and sort them with regard to their utility
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137 | var visitablePoints = (
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138 | from point in Enumerable.Range(0, numPoints)
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139 | // Calculate the distance when going from the starting point to this point and then to the end point
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140 | let distance = distances[startingPoint, point] + distances[point, terminusPoint] + fixedPenalty
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141 | // If this distance is feasible and the point is neither starting nor ending point, check the point
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142 | where distance < maxDistance && point != startingPoint && point != terminusPoint
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143 | // The point was not yet visited, so add it to the candidate list
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144 | where !initialTour.Contains(point)
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145 | // Calculate the utility of the point at this position
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146 | let utility = scores[point]
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147 | orderby utility
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148 | select point
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149 | ).ToList();
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150 |
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151 | // Initialize the new tour
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152 | var actualTour = new List<int> { startingPoint };
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153 |
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154 | // Perform the insertions according to the utility sorting
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155 | InsertPoints(actualTour, initialTour, neighborhood, visitablePoints, random);
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156 |
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157 | // Bring the tour back to be feasible
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158 | CleanupTour(actualTour, distances, maxDistance, fixedPenalty);
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159 |
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160 | // Set new Tour
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161 | IntegerVectorParameter.ActualValue = new IntegerVector(actualTour.ToArray());
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162 | }
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163 |
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164 | return base.Apply();
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165 | }
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166 | private void InsertPoints(List<int> actualTour, IntegerVector initialTour,
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167 | int neighborhood, List<int> visitablePoints, IRandom random) {
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168 |
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169 | // Elect the starting index of the part to be replaced
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170 | int tourSize = initialTour.Length;
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171 | int randomPosition = random.Next(tourSize - neighborhood - 1) + 1;
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172 |
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173 | for (int position = 1; position < tourSize; position++) {
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174 | if ((position < randomPosition) || (position > (randomPosition + neighborhood - 1))) {
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175 | // Copy from initial tour when outside shaking range
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176 | actualTour.Add(initialTour[position]);
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177 |
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178 | // Delete this point from the candidate list
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179 | visitablePoints.Remove(initialTour[position]);
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180 | } else {
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181 | // Point from within shaking range
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182 | if (visitablePoints.Count > 0) {
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183 | // Add the point with the highest utility from the candidate list
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184 | int randomFactor = random.Next(3);
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185 | int insertionIndex = visitablePoints.Count - 1;
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186 | if (visitablePoints.Count > 4) insertionIndex -= randomFactor;
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187 |
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188 | actualTour.Add(visitablePoints[insertionIndex]);
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189 |
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190 | // Delete this point from the candidate list
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191 | visitablePoints.RemoveAt(insertionIndex);
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192 | } else {
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193 | // We don't have any points left that could be inserted so we can only re-insert
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194 | // the removed and not already re-inserted points in a random order
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195 | for (int reinsertPosition = randomPosition; reinsertPosition < randomPosition + neighborhood; reinsertPosition++) {
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196 | bool alreadyReinserted = actualTour.Contains(initialTour[reinsertPosition]);
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197 |
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198 | if (!alreadyReinserted)
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199 | visitablePoints.Add(initialTour[reinsertPosition]);
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200 | }
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201 |
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202 | int randomIndex = random.Next(visitablePoints.Count);
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203 | actualTour.Add(visitablePoints[randomIndex]);
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204 | visitablePoints.Clear();
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205 | }
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206 | }
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207 | }
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208 | }
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209 | private void CleanupTour(List<int> actualTour, DistanceMatrix distances, double maxDistance, double fixedPenalty) {
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210 | // Sort the points on the tour according to their costs savings when removed
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211 | var distanceSavings = (
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212 | from removePosition in Enumerable.Range(1, actualTour.Count - 2)
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213 | let saving = distances.CalculateRemovementSaving(actualTour, removePosition, fixedPenalty)
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214 | orderby saving descending
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215 | select new SavingInfo { Index = removePosition, Saving = saving }
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216 | ).ToList();
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217 |
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218 | //double tourLength = distances.CalculateTourLength(actualTour, fixedPenalty);
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219 |
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220 | // As long as the created path is infeasible, remove elements
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221 | while (distances.CalculateTourLength(actualTour, fixedPenalty) > maxDistance) {
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222 | // Remove the point that frees the largest distance
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223 | actualTour.RemoveAt(distanceSavings[0].Index);
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224 | //tourLength -= distanceSavings[0].Saving;
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225 |
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226 | // Shift indices due to removal of a point in the tour
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227 | for (int i = 1; i < distanceSavings.Count; i++) {
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228 | if (distanceSavings[i].Index > distanceSavings[0].Index) {
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229 | distanceSavings[i].Index--;
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230 | // Note, distance savings are not updated after removal
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231 | }
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232 | }
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233 | distanceSavings.RemoveAt(0);
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234 | }
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235 | }
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236 | //
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237 | private class SavingInfo {
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238 | public int Index;
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239 | public double Saving;
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240 | }
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241 | }
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242 | } |
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