Free cookie consent management tool by TermsFeed Policy Generator

source: branches/VRP/HeuristicLab.Problems.VehicleRouting/3.4/Encodings/Potvin/PotvinEncoding.cs @ 7543

Last change on this file since 7543 was 7543, checked in by svonolfe, 12 years ago

Fixed minor issues (#1177)

File size: 8.2 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      solution.Tours = new ItemList<Tour>();
133
134      Tour tour = new Tour();
135      int routeIdx = 0;
136      for (int i = 0; i < route.Count; i++) {
137        if (route[i] <= 0) {
138          if (tour.Stops.Count > 0) {
139            solution.Tours.Add(tour);
140            tour = new Tour();
141          }
142          int vehicle = -route[i];
143          solution.VehicleAssignment[routeIdx] = vehicle;
144          routeIdx++;
145        } else {
146          tour.Stops.Add(route[i]);
147        }
148      }
149
150      solution.Repair();
151
152      return solution;
153    }
154
155    public double GetTourLength(Tour tour) {
156      return tour.GetTourLength(ProblemInstance, this);
157    }
158
159    public int FindBestInsertionPlace(Tour tour, int city, int positionToAvoid = -1) {
160      if (tour.Stops.Count == 0)
161        return 0;
162     
163      int place = -1;
164      double minQuality = -1;
165
166      VRPEvaluation eval = ProblemInstance.EvaluateTour(tour, this);
167
168      for (int i = 0; i <= tour.Stops.Count; i++) {
169        if (positionToAvoid != i) {
170          bool feasible;
171          double quality = ProblemInstance.GetInsertionCosts(eval, this, city, 0, i, out feasible);
172          if (place < 0 || quality < minQuality) {
173            place = i;
174            minQuality = quality;
175          }
176        }
177      }
178
179      if (place == -1)
180        place = 0;
181
182      return place;
183    }
184
185    public void InsertPair(Tour tour, int source, int target, IVRPProblemInstance problemInstance, int positionToAvoid = -1, int positionToAvoid2 = -1) {
186      int stops = tour.Stops.Count;
187      VRPEvaluation eval = problemInstance.EvaluateTour(tour, this);
188      double minCosts = double.MaxValue;
189      int sourceLocation = -1;
190      int targetLocation = -1;
191
192      for (int i = 0; i <= stops; i++) {
193        tour.Stops.Insert(i, source);
194        VRPEvaluation tourEval = problemInstance.EvaluateTour(tour, this);
195        double sourceCosts = tourEval.Quality - eval.Quality;
196
197        for (int j = i + 1; j <= stops + 1; j++) {
198          if (positionToAvoid != i || positionToAvoid2 != j || stops == 0) {
199            bool feasible;
200            double targetCosts = problemInstance.GetInsertionCosts(tourEval, this, target, 0, j, out feasible);
201
202            double costs = sourceCosts + targetCosts;
203            if (costs < minCosts) {
204              minCosts = costs;
205              sourceLocation = i;
206              targetLocation = j;
207            }
208          }
209        }
210        tour.Stops.Remove(source);
211      }
212
213      tour.Stops.Insert(sourceLocation, source);
214      tour.Stops.Insert(targetLocation, target);
215    }
216
217    public bool FindInsertionPlace(int city, int routeToAvoid, bool allowInfeasible, out int route, out int place) {
218      route = -1;
219      place = -1;
220      double minDetour = double.MaxValue;
221
222      VRPEvaluation eval = ProblemInstance.Evaluate(this);
223      bool originalFeasible = ProblemInstance.Feasible(eval);
224
225      for (int tour = 0; tour < Tours.Count; tour++) {
226        if (tour != routeToAvoid) {
227          double length = eval.Quality;
228
229          for (int i = 0; i <= Tours[tour].Stops.Count; i++) {
230            bool feasible;
231            double detour = ProblemInstance.GetInsertionCosts(eval, this, city, tour, i, out feasible);
232
233            if (feasible || allowInfeasible) {
234              if (route < 0 || detour < minDetour) {
235                route = tour;
236                place = i;
237                minDetour = detour;
238              }
239            }
240          }
241        }
242      }
243
244      return route >= 0 && place >= 0;
245    }
246  }
247}
Note: See TracBrowser for help on using the repository browser.