source: branches/VRP/HeuristicLab.Problems.VehicleRouting/3.4/Encodings/Potvin/PotvinEncoding.cs @ 6960

Last change on this file since 6960 was 6960, checked in by svonolfe, 11 years ago

Added pairwise manipulators, removed relocation manipulator (#1177)

File size: 7.8 KB
Line 
1#region License Information
2/* HeuristicLab
3 * Copyright (C) 2002-2010 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 HeuristicLab.Common;
23using HeuristicLab.Core;
24using HeuristicLab.Data;
25using HeuristicLab.Encodings.PermutationEncoding;
26using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
27using System.Drawing;
28using System.Collections.Generic;
29using HeuristicLab.Problems.VehicleRouting.Encodings.General;
30using HeuristicLab.Problems.VehicleRouting.Variants;
31using HeuristicLab.Problems.VehicleRouting.Interfaces;
32using HeuristicLab.Problems.VehicleRouting.ProblemInstances;
33
34namespace HeuristicLab.Problems.VehicleRouting.Encodings.Potvin {
35  [Item("PotvinEncoding", "Represents a potvin encoding of VRP solutions. It is implemented as described in Potvin, J.-Y. and Bengio, S. (1996). The Vehicle Routing Problem with Time Windows - Part II: Genetic Search. INFORMS Journal of Computing, 8:165–172.")]
36  [StorableClass]
37  public class PotvinEncoding : TourEncoding {   
38    [Storable]
39    public List<int> Unrouted { get; set; }
40
41    [Storable]
42    public Permutation VehicleAssignment { get; private set; }
43
44    public PotvinEncoding(IVRPProblemInstance instance)
45      : base(instance) {
46      Unrouted = new List<int>();
47      VehicleAssignment = new Permutation(PermutationTypes.Absolute, instance.Vehicles.Value);
48    }
49
50    [StorableConstructor]
51    protected PotvinEncoding(bool serializing)
52      : base(serializing) {
53    }
54
55    public override IDeepCloneable Clone(Cloner cloner) {
56      return new PotvinEncoding(this, cloner);
57    }
58
59    protected PotvinEncoding(PotvinEncoding original, Cloner cloner)
60      : base(original, cloner) {
61        this.Unrouted = new List<int>(original.Unrouted);
62        this.VehicleAssignment = cloner.Clone<Permutation>(original.VehicleAssignment);
63    }
64
65    public override void Repair() {
66      List<Tour> toBeRemoved = new List<Tour>();
67      foreach (Tour tour in Tours) {
68        if (tour.Stops.Count == 0)
69          toBeRemoved.Add(tour);
70      }
71
72      foreach (Tour tour in toBeRemoved) {
73        int index = Tours.IndexOf(tour);
74        if (index < VehicleAssignment.Length) {
75          int vehicle = VehicleAssignment[index];
76
77          Tours.Remove(tour);
78          for (int i = index; i < VehicleAssignment.Length - 1; i++) {
79            VehicleAssignment[i] = VehicleAssignment[i + 1];
80          }
81          VehicleAssignment[VehicleAssignment.Length - 1] = vehicle;
82        }
83      }
84
85      while (Tours.Count > ProblemInstance.Vehicles.Value) {
86        Tour tour = Tours[Tours.Count - 1];
87        Tours[Tours.Count - 2].Stops.AddRange(tour.Stops);
88
89        Tours.Remove(tour);
90      }
91    }
92
93    public override int GetVehicleAssignment(int tour) {
94      return VehicleAssignment[tour];
95    }
96
97    public static PotvinEncoding ConvertFrom(IVRPEncoding encoding, IVRPProblemInstance instance) {
98      PotvinEncoding solution = new PotvinEncoding(instance);
99
100      TourEncoding.ConvertFrom(encoding, solution, instance);
101
102      List<int> vehicles = new List<int>();
103      for (int i = 0; i < instance.Vehicles.Value; i++)
104        vehicles.Add(i);
105
106      int[] assignment = new int[instance.Vehicles.Value];
107      for (int i = 0; i < assignment.Length; i++)
108        assignment[i] = -1;
109
110      for (int i = 0; i < solution.Tours.Count; i++) {
111        int vehicle = encoding.GetVehicleAssignment(i);
112        assignment[i] = vehicle;
113        vehicles.Remove(vehicle);
114      }
115
116      for (int i = 0; i < instance.Vehicles.Value; i++) {
117        if (assignment[i] == -1) {
118          int vehicle = vehicles[0];
119          assignment[i] = vehicle;
120          vehicles.RemoveAt(0);
121        }
122      }
123
124      solution.VehicleAssignment = new Permutation(PermutationTypes.Absolute, assignment);
125
126      return solution;
127    }
128
129    public static PotvinEncoding ConvertFrom(List<int> route, IVRPProblemInstance instance) {
130      PotvinEncoding solution = new PotvinEncoding(instance);
131
132      TourEncoding.ConvertFrom(route, solution);
133
134      return solution;
135    }
136
137    public double GetTourLength(Tour tour) {
138      return tour.GetTourLength(ProblemInstance, this);
139    }
140
141    public int FindBestInsertionPlace(Tour tour, int city, int positionToAvoid = -1) {
142      if (tour.Stops.Count == 0)
143        return 0;
144     
145      int place = -1;
146      double minQuality = -1;
147
148      VRPEvaluation eval = ProblemInstance.EvaluateTour(tour, this);
149
150      for (int i = 0; i <= tour.Stops.Count; i++) {
151        if (positionToAvoid != i) {
152          bool feasible;
153          double quality = ProblemInstance.GetInsertionCosts(eval, this, city, 0, i, out feasible);
154          if (place < 0 || quality < minQuality) {
155            place = i;
156            minQuality = quality;
157          }
158        }
159      }
160
161      if (place == -1)
162        place = 0;
163
164      return place;
165    }
166
167    public void InsertPair(Tour tour, int source, int target, IVRPProblemInstance problemInstance, int positionToAvoid = -1, int positionToAvoid2 = -1) {
168      int stops = tour.Stops.Count;
169      VRPEvaluation eval = problemInstance.EvaluateTour(tour, this);
170      double minCosts = double.MaxValue;
171      int sourceLocation = -1;
172      int targetLocation = -1;
173
174      for (int i = 0; i <= stops; i++) {
175        tour.Stops.Insert(i, source);
176        VRPEvaluation tourEval = problemInstance.EvaluateTour(tour, this);
177        double sourceCosts = tourEval.Quality - eval.Quality;
178
179        for (int j = i + 1; j <= stops + 1; j++) {
180          if (positionToAvoid != i || positionToAvoid2 != j || stops == 0) {
181            bool feasible;
182            double targetCosts = problemInstance.GetInsertionCosts(tourEval, this, target, 0, j, out feasible);
183
184            double costs = sourceCosts + targetCosts;
185            if (costs < minCosts) {
186              minCosts = costs;
187              sourceLocation = i;
188              targetLocation = j;
189            }
190          }
191        }
192        tour.Stops.Remove(source);
193      }
194
195      tour.Stops.Insert(sourceLocation, source);
196      tour.Stops.Insert(targetLocation, target);
197    }
198
199    public bool FindInsertionPlace(int city, int routeToAvoid, bool allowInfeasible, out int route, out int place) {
200      route = -1;
201      place = -1;
202      double minDetour = double.MaxValue;
203
204      VRPEvaluation eval = ProblemInstance.Evaluate(this);
205      bool originalFeasible = ProblemInstance.Feasible(eval);
206
207      for (int tour = 0; tour < Tours.Count; tour++) {
208        if (tour != routeToAvoid) {
209          double length = eval.Quality;
210
211          for (int i = 0; i <= Tours[tour].Stops.Count; i++) {
212            bool feasible;
213            double detour = ProblemInstance.GetInsertionCosts(eval, this, city, tour, i, out feasible);
214
215            if (feasible || allowInfeasible) {
216              if (route < 0 || detour < minDetour) {
217                route = tour;
218                place = i;
219                minDetour = detour;
220              }
221            }
222          }
223        }
224      }
225
226      return route >= 0 && place >= 0;
227    }
228  }
229}
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