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source: trunk/sources/HeuristicLab.Algorithms.EvolutionStrategy/3.3/WithoutRepeatingBatchedRandomSelector.cs @ 4068

Last change on this file since 4068 was 4068, checked in by swagner, 14 years ago

Sorted usings and removed unused usings in entire solution (#1094)

File size: 3.2 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 System;
23using System.Collections.Generic;
24using HeuristicLab.Core;
25using HeuristicLab.Data;
26using HeuristicLab.Parameters;
27using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
28using HeuristicLab.Selection;
29
30namespace HeuristicLab.Algorithms.EvolutionStrategy {
31  [Item("WithoutRepeatingBatchedRandomSelector", "Selects m batches of n parents where in each batch the n parents are drawn without repeating.")]
32  [StorableClass]
33  public class WithoutRepeatingBatchedRandomSelector : StochasticSelector {
34    public override bool CanChangeName {
35      get { return true; }
36    }
37    public IValueLookupParameter<IntValue> ChildrenParameter {
38      get { return (IValueLookupParameter<IntValue>)Parameters["Children"]; }
39    }
40    public IValueLookupParameter<IntValue> ParentsPerChildParameter {
41      get { return (IValueLookupParameter<IntValue>)Parameters["ParentsPerChild"]; }
42    }
43
44    public WithoutRepeatingBatchedRandomSelector()
45      : base() {
46      Parameters.Add(new ValueLookupParameter<IntValue>("Children", "The number of children to select (number of batches)."));
47      Parameters.Add(new ValueLookupParameter<IntValue>("ParentsPerChild", "The number of parents per child (size of each batch)."));
48    }
49
50    protected override IScope[] Select(List<IScope> scopes) {
51      IRandom random = RandomParameter.ActualValue;
52      int children = ChildrenParameter.ActualValue.Value;
53      int parents = ParentsPerChildParameter.ActualValue.Value;
54      int parentsAvailable = scopes.Count;
55
56      if (parents > parentsAvailable)
57        throw new InvalidOperationException("WithoutRepeatingBatchedRandomSelector: Cannot select more parents per child than there are parents available");
58
59      IScope[] result = new IScope[children * parents];
60      int count = 0;
61      HashSet<int> selectedParents = new HashSet<int>();
62      for (int i = 0; i < children; i++) {
63        selectedParents.Clear();
64        for (int j = 0; j < parents; j++) {
65          int nextParent = j; // will be used in case parents == parentsAvailable
66          if (parents < parentsAvailable) {
67            do {
68              nextParent = random.Next(parentsAvailable);
69            } while (selectedParents.Contains(nextParent));
70          }
71
72          result[count++] = (IScope)scopes[nextParent].Clone();
73          selectedParents.Add(nextParent);
74        }
75      }
76
77      return result;
78    }
79  }
80}
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