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source: trunk/sources/HeuristicLab.Problems.VehicleRouting/3.4/Encodings/Prins/Manipulators/PrinsStochasticLSManipulator.cs @ 14615

Last change on this file since 14615 was 14185, checked in by swagner, 8 years ago

#2526: Updated year of copyrights in license headers

File size: 3.2 KB
Line 
1#region License Information
2/* HeuristicLab
3 * Copyright (C) 2002-2016 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 System.Collections.Generic;
23using HeuristicLab.Common;
24using HeuristicLab.Core;
25using HeuristicLab.Data;
26using HeuristicLab.Parameters;
27using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
28
29namespace HeuristicLab.Problems.VehicleRouting.Encodings.Prins {
30  [Item("PrinsStochasticLSManipulator", "An operator which manipulates a VRP representation by using the stochastic version of the Prins local search.  It is implemented as described in Prins, C. (2004). A simple and effective evolutionary algorithm for the vehicle routing problem. Computers & Operations Research, 12:1985-2002.")]
31  [StorableClass]
32  public sealed class PrinsStochasticLSManipulator : PrinsLSManipulator {
33    public IValueParameter<IntValue> SampleSize {
34      get { return (IValueParameter<IntValue>)Parameters["SampleSize"]; }
35    }
36
37    [StorableConstructor]
38    private PrinsStochasticLSManipulator(bool deserializing) : base(deserializing) { }
39
40    public PrinsStochasticLSManipulator()
41      : base() {
42      Parameters.Add(new ValueParameter<IntValue>("SampleSize", "The sample size.", new IntValue(200)));
43    }
44
45    public override IDeepCloneable Clone(Cloner cloner) {
46      return new PrinsStochasticLSManipulator(this, cloner);
47    }
48
49    private PrinsStochasticLSManipulator(PrinsStochasticLSManipulator original, Cloner cloner)
50      : base(original, cloner) {
51    }
52
53    protected override void Manipulate(IRandom random, PrinsEncoding individual) {
54      List<Tour> tours = individual.GetTours();
55      bool improvement = false;
56      int iterations = 0;
57
58      do {
59        improvement = false;
60        double originalQuality = GetQuality(individual);
61        PrinsEncoding child = null;
62
63        int samples = 0;
64        while (!improvement &&
65          samples < SampleSize.Value.Value) {
66          int u = random.Next(ProblemInstance.Cities.Value);
67          int v = random.Next(ProblemInstance.Cities.Value);
68
69          child = Manipulate(individual,
70                originalQuality, u, v);
71
72          improvement = child != null;
73
74          samples++;
75        }
76
77        if (improvement) {
78          for (int i = 0; i < child.Length; i++) {
79            individual[i] = child[i];
80          }
81        }
82
83        iterations++;
84      } while (improvement &&
85        iterations < Iterations.Value.Value);
86    }
87  }
88}
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