source: branches/DataPreprocessing/HeuristicLab.Problems.DataAnalysis.Symbolic/3.4/SymbolicExpressionTreeBacktransformator.cs @ 10869

Last change on this file since 10869 was 10869, checked in by pfleck, 6 years ago
  • implemented basic backtransformation without variable weights
File size: 2.8 KB
Line 
1#region License Information
2/* HeuristicLab
3 * Copyright (C) 2002-2013 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 System.Linq;
24using HeuristicLab.Encodings.SymbolicExpressionTreeEncoding;
25using HeuristicLab.Problems.DataAnalysis.Transformations;
26
27namespace HeuristicLab.Problems.DataAnalysis.Symbolic {
28  public class SymbolicExpressionTreeBacktransformator : IModelBacktransformator {
29    private readonly ITransformationMapper<ISymbolicExpressionTree> transformationMapper;
30
31    public SymbolicExpressionTreeBacktransformator(ITransformationMapper<ISymbolicExpressionTree> transformationMapper) {
32      this.transformationMapper = transformationMapper;
33    }
34
35    public void Backtransform(IDataAnalysisModel model, IEnumerable<ITransformation> transformations) {
36      var symbolicModel = (ISymbolicDataAnalysisModel)model;
37
38      foreach (var transformation in transformations) {
39        ApplyBacktransformation(transformation, symbolicModel.SymbolicExpressionTree);
40      }
41    }
42
43    private void ApplyBacktransformation(ITransformation transformation, ISymbolicExpressionTree symbolicExpressionTree) {
44      var variableNodes = symbolicExpressionTree.IterateNodesBreadth()
45        .Where(n => IsVariableNode(n, transformation.Column));
46
47      var transformationTree = transformationMapper.GenerateModel(transformation);
48      foreach (var variableNode in variableNodes) {
49        SwapTransformationTree(transformationTree, variableNode);
50      }
51    }
52
53    private void SwapTransformationTree(ISymbolicExpressionTree transformationTree, ISymbolicExpressionTreeNode targetNode) {
54      var parent = targetNode.Parent;
55      int index = parent.IndexOfSubtree(targetNode);
56      parent.RemoveSubtree(index);
57      parent.InsertSubtree(index, transformationTree.Root.GetSubtree(0));
58    }
59
60    private bool IsVariableNode(ISymbolicExpressionTreeNode node, string variableName) {
61      var variableNode = node as VariableTreeNode;
62      if (variableNode == null) return false;
63      return variableNode.VariableName == variableName;
64    }
65  }
66}
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