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source: branches/3.1/sources/HeuristicLab.StructureIdentification/RampedTreeCreator.cs @ 3508

Last change on this file since 3508 was 441, checked in by gkronber, 16 years ago

changed the way invalid trees are handled in the RampedTreeCreator (ticket #225)

File size: 3.9 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.Linq;
23using HeuristicLab.Core;
24using HeuristicLab.Data;
25using HeuristicLab.Operators;
26using System;
27using HeuristicLab.Random;
28using HeuristicLab.Functions;
29using System.Diagnostics;
30
31namespace HeuristicLab.StructureIdentification {
32  public class RampedTreeCreator : OperatorBase {
33    public override string Description {
34      get { return @"Generates a new random operator tree."; }
35    }
36
37    public RampedTreeCreator()
38      : base() {
39      AddVariableInfo(new VariableInfo("Random", "Uniform random number generator", typeof(MersenneTwister), VariableKind.In));
40      AddVariableInfo(new VariableInfo("OperatorLibrary", "The operator library containing all available operators", typeof(GPOperatorLibrary), VariableKind.In));
41      AddVariableInfo(new VariableInfo("MinTreeHeight", "The minimal allowed height of the tree", typeof(IntData), VariableKind.In));
42      AddVariableInfo(new VariableInfo("MaxTreeHeight", "The maximal allowed height of the tree", typeof(IntData), VariableKind.In));
43      AddVariableInfo(new VariableInfo("BalancedTreesRate", "Determines how many trees should be balanced", typeof(DoubleData), VariableKind.In));
44      AddVariableInfo(new VariableInfo("FunctionTree", "The created tree", typeof(IFunctionTree), VariableKind.New | VariableKind.Out));
45      AddVariableInfo(new VariableInfo("TreeSize", "The size (number of nodes) of the tree", typeof(IntData), VariableKind.New | VariableKind.Out));
46      AddVariableInfo(new VariableInfo("TreeHeight", "The height of the tree", typeof(IntData), VariableKind.New | VariableKind.Out));
47    }
48
49    public override IOperation Apply(IScope scope) {
50      IRandom random = GetVariableValue<IRandom>("Random", scope, true);
51      GPOperatorLibrary opLibrary = GetVariableValue<GPOperatorLibrary>("OperatorLibrary", scope, true);
52      int minTreeHeight = GetVariableValue<IntData>("MinTreeHeight", scope, true).Data;
53      int maxTreeHeight = GetVariableValue<IntData>("MaxTreeHeight", scope, true).Data;
54      double balancedTreesRate = GetVariableValue<DoubleData>("BalancedTreesRate", scope, true).Data;
55
56      TreeGardener gardener = new TreeGardener(random, opLibrary);
57
58      int treeHeight = random.Next(minTreeHeight, maxTreeHeight + 1);
59      IFunctionTree root;
60      if(random.NextDouble() <= balancedTreesRate) {
61        root = gardener.CreateBalancedRandomTree(Int32.MaxValue, treeHeight);
62      } else {
63        root = gardener.CreateUnbalancedRandomTree(Int32.MaxValue, treeHeight);
64      }
65
66      int actualTreeSize = root.Size;
67      int actualTreeHeight = root.Height;
68
69      scope.AddVariable(new HeuristicLab.Core.Variable(scope.TranslateName("FunctionTree"), root));
70      scope.AddVariable(new HeuristicLab.Core.Variable(scope.TranslateName("TreeSize"), new IntData(actualTreeSize)));
71      scope.AddVariable(new HeuristicLab.Core.Variable(scope.TranslateName("TreeHeight"), new IntData(actualTreeHeight)));
72
73      Debug.Assert(gardener.IsValidTree(root) && actualTreeHeight <= maxTreeHeight);
74
75      return gardener.CreateInitializationOperation(gardener.GetAllSubTrees(root), scope);
76    }
77  }
78}
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