[14843] | 1 | #region License Information
|
---|
| 2 | /* HeuristicLab
|
---|
[17687] | 3 | * Copyright (C) Heuristic and Evolutionary Algorithms Laboratory (HEAL)
|
---|
[14843] | 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 |
|
---|
| 22 | using System.Collections.Generic;
|
---|
| 23 | using System.Linq;
|
---|
| 24 | using HeuristicLab.Common;
|
---|
| 25 | using HeuristicLab.Encodings.SymbolicExpressionTreeEncoding;
|
---|
| 26 |
|
---|
| 27 | namespace HeuristicLab.Problems.DataAnalysis.Symbolic {
|
---|
| 28 | public class SymbolicExpressionTreeBacktransformator : IModelBacktransformator {
|
---|
| 29 | private readonly ITransformationMapper<ISymbolicExpressionTreeNode> transformationMapper;
|
---|
| 30 |
|
---|
| 31 | public SymbolicExpressionTreeBacktransformator(ITransformationMapper<ISymbolicExpressionTreeNode> transformationMapper) {
|
---|
| 32 | this.transformationMapper = transformationMapper;
|
---|
| 33 | }
|
---|
| 34 |
|
---|
| 35 | public ISymbolicDataAnalysisModel Backtransform(ISymbolicDataAnalysisModel model, IEnumerable<ITransformation> transformations, string targetVariable) {
|
---|
| 36 | var symbolicModel = (ISymbolicDataAnalysisModel)model.Clone();
|
---|
| 37 |
|
---|
| 38 | foreach (var transformation in transformations.Reverse()) {
|
---|
| 39 | ApplyBacktransformation(transformation, symbolicModel.SymbolicExpressionTree, targetVariable);
|
---|
| 40 | }
|
---|
| 41 |
|
---|
| 42 | return symbolicModel;
|
---|
| 43 | }
|
---|
| 44 |
|
---|
| 45 | private void ApplyBacktransformation(ITransformation transformation, ISymbolicExpressionTree symbolicExpressionTree, string targetVariable) {
|
---|
| 46 | if (transformation.Column != targetVariable) {
|
---|
| 47 | var variableNodes = symbolicExpressionTree.IterateNodesBreadth()
|
---|
| 48 | .OfType<VariableTreeNode>()
|
---|
| 49 | .Where(n => n.VariableName == transformation.Column);
|
---|
| 50 | ApplyRegularBacktransformation(transformation, variableNodes);
|
---|
| 51 | } else if (!(transformation is CopyColumnTransformation)) {
|
---|
| 52 | ApplyInverseBacktransformation(transformation, symbolicExpressionTree);
|
---|
| 53 | }
|
---|
| 54 | }
|
---|
| 55 |
|
---|
| 56 | private void ApplyRegularBacktransformation(ITransformation transformation, IEnumerable<VariableTreeNode> variableNodes) {
|
---|
| 57 | foreach (var variableNode in variableNodes) {
|
---|
| 58 | // generate new subtrees because same subtree cannot be added more than once
|
---|
| 59 | var transformationTree = transformationMapper.GenerateModel(transformation);
|
---|
| 60 | SwapVariableWithTree(variableNode, transformationTree);
|
---|
| 61 | }
|
---|
| 62 | }
|
---|
| 63 |
|
---|
| 64 | private void ApplyInverseBacktransformation(ITransformation transformation, ISymbolicExpressionTree symbolicExpressionTree) {
|
---|
| 65 | var startSymbol = symbolicExpressionTree.Root.GetSubtree(0);
|
---|
| 66 | var modelTree = startSymbol.GetSubtree(0);
|
---|
| 67 | startSymbol.RemoveSubtree(0);
|
---|
| 68 |
|
---|
| 69 | var transformationTree = transformationMapper.GenerateInverseModel(transformation);
|
---|
| 70 | var variableNode = transformationTree.IterateNodesBreadth()
|
---|
| 71 | .OfType<VariableTreeNode>()
|
---|
| 72 | .Single(n => n.VariableName == transformation.Column);
|
---|
| 73 |
|
---|
| 74 | SwapVariableWithTree(variableNode, modelTree);
|
---|
| 75 |
|
---|
| 76 | startSymbol.AddSubtree(transformationTree);
|
---|
| 77 | }
|
---|
| 78 |
|
---|
| 79 | private void SwapVariableWithTree(VariableTreeNode variableNode, ISymbolicExpressionTreeNode treeNode) {
|
---|
| 80 | var parent = variableNode.Parent;
|
---|
| 81 | int index = parent.IndexOfSubtree(variableNode);
|
---|
| 82 | parent.RemoveSubtree(index);
|
---|
| 83 |
|
---|
| 84 | if (!variableNode.Weight.IsAlmost(1.0))
|
---|
| 85 | treeNode = CreateNodeFromWeight(treeNode, variableNode);
|
---|
| 86 |
|
---|
| 87 | parent.InsertSubtree(index, treeNode);
|
---|
| 88 | }
|
---|
| 89 |
|
---|
| 90 | private ISymbolicExpressionTreeNode CreateNodeFromWeight(ISymbolicExpressionTreeNode transformationTree, VariableTreeNode variableNode) {
|
---|
| 91 | var multiplicationNode = new SymbolicExpressionTreeNode(new Multiplication());
|
---|
| 92 | multiplicationNode.AddSubtree(new ConstantTreeNode(new Constant()) { Value = variableNode.Weight });
|
---|
| 93 | multiplicationNode.AddSubtree(transformationTree);
|
---|
| 94 | return multiplicationNode;
|
---|
| 95 | }
|
---|
| 96 | }
|
---|
| 97 | }
|
---|