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source: branches/Persistence Test/HeuristicLab.GP.Operators/3.3/Recombination/GPCrossoverBase.cs @ 2491

Last change on this file since 2491 was 2222, checked in by gkronber, 15 years ago

Merged changes from GP-refactoring branch back into the trunk #713.

File size: 2.7 KB
Line 
1#region License Information
2/* HeuristicLab
3 * Copyright (C) 2002-2008 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 HeuristicLab.Core;
24using System.Diagnostics;
25using HeuristicLab.Evolutionary;
26using HeuristicLab.GP.Interfaces;
27
28namespace HeuristicLab.GP.Operators {
29  public abstract class GPCrossoverBase : CrossoverBase {
30    public GPCrossoverBase()
31      : base() {
32      AddVariableInfo(new VariableInfo("FunctionLibrary", "The operator library containing all available operators", typeof(FunctionLibrary), VariableKind.In));
33      AddVariableInfo(new VariableInfo("FunctionTree", "The tree to crossover", typeof(IGeneticProgrammingModel), VariableKind.In | VariableKind.New));
34    }
35
36    internal abstract IFunctionTree Cross(IScope scope, TreeGardener gardener, IRandom random, IFunctionTree tree0, IFunctionTree tree1);
37
38    protected override void Cross(IScope scope, IRandom random) {
39      FunctionLibrary opLibrary = GetVariableValue<FunctionLibrary>("FunctionLibrary", scope, true);
40      TreeGardener gardener = new TreeGardener(random, opLibrary);
41
42      if (scope.SubScopes.Count != 2)
43        throw new InvalidOperationException("Number of parents must be exactly two.");
44
45      IGeneticProgrammingModel parent0 = GetVariableValue<IGeneticProgrammingModel>("FunctionTree", scope.SubScopes[0], false);
46      IGeneticProgrammingModel parent1 = GetVariableValue<IGeneticProgrammingModel>("FunctionTree", scope.SubScopes[1], false);
47
48      // randomly swap parents to remove a possible bias from selection (e.g. when using gender-specific selection)
49      if (random.NextDouble() < 0.5) {
50        IGeneticProgrammingModel tmp = parent0;
51        parent0 = parent1;
52        parent1 = tmp;
53      }
54
55      IFunctionTree child = Cross(scope, gardener, random, parent0.FunctionTree, parent1.FunctionTree);
56      Debug.Assert(gardener.IsValidTree(child));
57      scope.AddVariable(new HeuristicLab.Core.Variable(scope.TranslateName("FunctionTree"), new GeneticProgrammingModel(child)));
58    }
59  }
60}
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