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source: branches/GP-MoveOperators/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/ReplaceBranchMoveMaker.cs @ 8214

Last change on this file since 8214 was 8214, checked in by gkronber, 10 years ago

#1847: bug fixes and improvements discussed with andreas

File size: 5.3 KB
Line 
1#region License Information
2/* HeuristicLab
3 * Copyright (C) 2002-2012 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.SymbolicExpressionTreeEncoding;
26using HeuristicLab.Operators;
27using HeuristicLab.Optimization;
28using HeuristicLab.Parameters;
29using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
30
31namespace HeuristicLab.Problems.DataAnalysis.Symbolic.Regression {
32  [Item("ReplaceBranchMoveMaker", "")]
33  [StorableClass]
34  public class ReplaceBranchMoveMaker : SingleSuccessorOperator, ISymbolicExpressionTreeMoveOperator, IMoveMaker {
35    public override bool CanChangeName {
36      get { return false; }
37    }
38    public ILookupParameter<DoubleValue> QualityParameter {
39      get { return (ILookupParameter<DoubleValue>)Parameters["Quality"]; }
40    }
41    public ILookupParameter<DoubleValue> MoveQualityParameter {
42      get { return (ILookupParameter<DoubleValue>)Parameters["MoveQuality"]; }
43    }
44    public ILookupParameter<ReplaceBranchMove> ReplaceBranchMoveParameter {
45      get { return (ILookupParameter<ReplaceBranchMove>)Parameters["ReplaceBranchMove"]; }
46    }
47    public ILookupParameter<ISymbolicExpressionTree> SymbolicExpressionTreeParameter {
48      get { return (ILookupParameter<ISymbolicExpressionTree>)Parameters["SymbolicExpressionTree"]; }
49    }
50
51    [StorableConstructor]
52    protected ReplaceBranchMoveMaker(bool deserializing) : base(deserializing) { }
53    protected ReplaceBranchMoveMaker(ReplaceBranchMoveMaker original, Cloner cloner) : base(original, cloner) { }
54    public ReplaceBranchMoveMaker()
55      : base() {
56      Parameters.Add(new LookupParameter<DoubleValue>("Quality", "The quality of the solution."));
57      Parameters.Add(new LookupParameter<ReplaceBranchMove>("ReplaceBranchMove", "The move to evaluate."));
58      Parameters.Add(new LookupParameter<DoubleValue>("MoveQuality", "The relative quality of the move."));
59      Parameters.Add(new LookupParameter<ISymbolicExpressionTree>("SymbolicExpressionTree", "The symbolic expression tree on which the move should be applied."));
60    }
61
62    public override IDeepCloneable Clone(Cloner cloner) {
63      return new ReplaceBranchMoveMaker(this, cloner);
64    }
65
66    public override IOperation Apply() {
67      var move = ReplaceBranchMoveParameter.ActualValue;
68      DoubleValue moveQuality = MoveQualityParameter.ActualValue;
69      DoubleValue quality = QualityParameter.ActualValue;
70
71      var newNode = (ISymbolicExpressionTreeNode)move.NewBranch.Clone();
72      move.Parent.RemoveSubtree(move.SubtreeIndex);
73      move.Parent.InsertSubtree(move.SubtreeIndex, Scale(newNode, move.Alpha, move.Beta));
74
75      quality.Value = moveQuality.Value;
76      // update solution
77      SymbolicExpressionTreeParameter.ActualValue = move.Tree;
78
79      return base.Apply();
80    }
81
82
83    private Addition add = new Addition();
84    private Multiplication mul = new Multiplication();
85    private Constant constant = new Constant();
86
87    private ISymbolicExpressionTreeNode Scale(ISymbolicExpressionTreeNode node, double alpha, double beta) {
88      var constNode = node as ConstantTreeNode;
89      if (constNode != null) {
90        constNode.Value = constNode.Value * beta + alpha;
91        return constNode;
92      }
93      var varNode = node as VariableTreeNode;
94      if (varNode != null) {
95        varNode.Weight = varNode.Weight * beta;
96        var constAlpha = (ConstantTreeNode)constant.CreateTreeNode();
97        constAlpha.Value = alpha;
98        var sum = add.CreateTreeNode();
99        sum.AddSubtree(varNode); sum.AddSubtree(constAlpha);
100        return sum;
101      }
102      if (node.Symbol is Addition && node.GetSubtree(0).Symbol is Multiplication &&
103        node.GetSubtree(1).Symbol is Constant && node.GetSubtree(0).GetSubtree(1).Symbol is Constant) {
104        var constAlpha = node.GetSubtree(1) as ConstantTreeNode;
105        var constBeta = node.GetSubtree(0).GetSubtree(1) as ConstantTreeNode;
106        constAlpha.Value = beta * constAlpha.Value + alpha;
107        constBeta.Value = constBeta.Value * beta;
108        return node;
109      } else {
110        var constAlpha = (ConstantTreeNode)constant.CreateTreeNode();
111        var constBeta = (ConstantTreeNode)constant.CreateTreeNode();
112        constAlpha.Value = alpha;
113        constBeta.Value = beta;
114        var sum = add.CreateTreeNode();
115        var prod = mul.CreateTreeNode();
116        prod.AddSubtree(node);
117        prod.AddSubtree(constBeta);
118        sum.AddSubtree(prod);
119        sum.AddSubtree(constAlpha);
120        return sum;
121      }
122    }
123  }
124}
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