1 | #region License Information
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2 | /* HeuristicLab
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3 | * Copyright (C) Heuristic and Evolutionary Algorithms Laboratory (HEAL)
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4 | *
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5 | * This file is part of HeuristicLab.
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6 | *
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7 | * HeuristicLab is free software: you can redistribute it and/or modify
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8 | * it under the terms of the GNU General Public License as published by
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9 | * the Free Software Foundation, either version 3 of the License, or
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10 | * (at your option) any later version.
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11 | *
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12 | * HeuristicLab is distributed in the hope that it will be useful,
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13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of
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14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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15 | * GNU General Public License for more details.
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16 | *
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17 | * You should have received a copy of the GNU General Public License
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18 | * along with HeuristicLab. If not, see <http://www.gnu.org/licenses/>.
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19 | */
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20 | #endregion
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21 |
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22 | #define EXPLICIT_SHAPE
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23 |
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24 | using System;
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25 | using System.Collections.Generic;
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26 | using System.Linq;
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27 | using HeuristicLab.Encodings.SymbolicExpressionTreeEncoding;
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28 | using NumSharp;
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29 | using Tensorflow;
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30 | using static Tensorflow.Binding;
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31 |
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32 | namespace HeuristicLab.Problems.DataAnalysis.Symbolic {
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33 | public class TreeToTensorConverter {
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34 |
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35 | private static readonly TF_DataType DataType = tf.float32;
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36 |
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37 | public static bool TryConvert(ISymbolicExpressionTree tree, int numRows, Dictionary<string, int> variableLengths,
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38 | bool makeVariableWeightsVariable, bool addLinearScalingTerms,
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39 | out Tensor graph, out Dictionary<Tensor, string> parameters, out List<Tensor> variables) {
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40 |
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41 | try {
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42 | var converter = new TreeToTensorConverter(numRows, variableLengths, makeVariableWeightsVariable, addLinearScalingTerms);
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43 | graph = converter.ConvertNode(tree.Root.GetSubtree(0));
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44 |
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45 | parameters = converter.parameters;
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46 | variables = converter.variables;
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47 | return true;
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48 | } catch (NotSupportedException) {
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49 | graph = null;
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50 | parameters = null;
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51 | variables = null;
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52 | return false;
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53 | }
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54 | }
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55 |
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56 | private readonly int numRows;
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57 | private readonly Dictionary<string, int> variableLengths;
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58 | private readonly bool makeVariableWeightsVariable;
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59 | private readonly bool addLinearScalingTerms;
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60 |
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61 | private readonly Dictionary<Tensor, string> parameters = new Dictionary<Tensor, string>();
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62 | private readonly List<Tensor> variables = new List<Tensor>();
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63 |
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64 | private TreeToTensorConverter(int numRows, Dictionary<string, int> variableLengths, bool makeVariableWeightsVariable, bool addLinearScalingTerms) {
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65 | this.numRows = numRows;
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66 | this.variableLengths = variableLengths;
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67 | this.makeVariableWeightsVariable = makeVariableWeightsVariable;
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68 | this.addLinearScalingTerms = addLinearScalingTerms;
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69 | }
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70 |
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71 |
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72 | private Tensor ConvertNode(ISymbolicExpressionTreeNode node) {
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73 | if (node.Symbol is Constant) {
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74 | var value = (float)((ConstantTreeNode)node).Value;
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75 | var value_arr = np.array(value).reshape(1, 1);
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76 | var var = tf.Variable(value_arr, name: $"c_{variables.Count}", dtype: DataType);
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77 | variables.Add(var);
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78 | return var;
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79 | }
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80 |
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81 | if (node.Symbol is Variable/* || node.Symbol is BinaryFactorVariable*/) {
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82 | var varNode = node as VariableTreeNodeBase;
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83 | //var factorVarNode = node as BinaryFactorVariableTreeNode;
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84 | // factor variable values are only 0 or 1 and set in x accordingly
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85 | //var varValue = factorVarNode != null ? factorVarNode.VariableValue : string.Empty;
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86 | //var par = FindOrCreateParameter(parameters, varNode.VariableName, varValue);
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87 | var par = tf.placeholder(DataType, new TensorShape(numRows, variableLengths[varNode.VariableName]), name: varNode.VariableName);
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88 | parameters.Add(par, varNode.VariableName);
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89 |
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90 | if (makeVariableWeightsVariable) {
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91 | var w_arr = np.array((float)varNode.Weight).reshape(1, 1);
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92 | var w = tf.Variable(w_arr, name: $"w_{varNode.VariableName}", dtype: DataType);
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93 | variables.Add(w);
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94 | return w * par;
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95 | } else {
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96 | return varNode.Weight * par;
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97 | }
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98 | }
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99 |
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100 | //if (node.Symbol is FactorVariable) {
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101 | // var factorVarNode = node as FactorVariableTreeNode;
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102 | // var products = new List<Tensor>();
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103 | // foreach (var variableValue in factorVarNode.Symbol.GetVariableValues(factorVarNode.VariableName)) {
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104 | // //var par = FindOrCreateParameter(parameters, factorVarNode.VariableName, variableValue);
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105 | // var par = tf.placeholder(DataType, new TensorShape(numRows, 1), name: factorVarNode.VariableName);
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106 | // parameters.Add(par, factorVarNode.VariableName);
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107 |
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108 | // var value = factorVarNode.GetValue(variableValue);
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109 | // //initialConstants.Add(value);
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110 | // var wVar = (RefVariable)tf.VariableV1(value, name: $"f_{factorVarNode.VariableName}_{variables.Count}", dtype: DataType, shape: new[] { 1, 1 });
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111 | // //var wVar = tf.Variable(value, name: $"f_{factorVarNode.VariableName}_{variables.Count}"/*, shape: new[] { 1, 1 }*/);
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112 | // variables.Add(wVar);
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113 |
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114 | // products.add(wVar * par);
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115 | // }
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116 |
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117 | // return products.Aggregate((a, b) => a + b);
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118 | //}
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119 |
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120 | if (node.Symbol is Addition) {
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121 | var terms = node.Subtrees.Select(ConvertNode).ToList();
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122 | return terms.Aggregate((a, b) => a + b);
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123 | }
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124 |
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125 | if (node.Symbol is Subtraction) {
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126 | var terms = node.Subtrees.Select(ConvertNode).ToList();
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127 | if (terms.Count == 1) return -terms[0];
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128 | return terms.Aggregate((a, b) => a - b);
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129 | }
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130 |
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131 | if (node.Symbol is Multiplication) {
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132 | var terms = node.Subtrees.Select(ConvertNode).ToList();
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133 | return terms.Aggregate((a, b) => a * b);
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134 | }
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135 |
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136 | if (node.Symbol is Division) {
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137 | var terms = node.Subtrees.Select(ConvertNode).ToList();
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138 | if (terms.Count == 1) return 1.0f / terms[0];
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139 | return terms.Aggregate((a, b) => a / b);
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140 | }
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141 |
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142 | if (node.Symbol is Absolute) {
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143 | var x1 = ConvertNode(node.GetSubtree(0));
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144 | return tf.abs(x1);
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145 | }
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146 |
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147 | if (node.Symbol is AnalyticQuotient) {
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148 | var x1 = ConvertNode(node.GetSubtree(0));
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149 | var x2 = ConvertNode(node.GetSubtree(1));
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150 | return x1 / tf.pow(1.0f + x2 * x2, 0.5f);
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151 | }
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152 |
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153 | if (node.Symbol is Logarithm) {
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154 | return math_ops.log(
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155 | ConvertNode(node.GetSubtree(0)));
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156 | }
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157 |
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158 | if (node.Symbol is Exponential) {
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159 | return math_ops.pow(
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160 | Math.E,
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161 | ConvertNode(node.GetSubtree(0)));
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162 | }
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163 |
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164 | if (node.Symbol is Square) {
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165 | return tf.square(
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166 | ConvertNode(node.GetSubtree(0)));
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167 | }
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168 |
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169 | if (node.Symbol is SquareRoot) {
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170 | return math_ops.sqrt(
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171 | ConvertNode(node.GetSubtree(0)));
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172 | }
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173 |
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174 | if (node.Symbol is Cube) {
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175 | return math_ops.pow(
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176 | ConvertNode(node.GetSubtree(0)), 3.0f);
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177 | }
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178 |
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179 | if (node.Symbol is CubeRoot) {
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180 | return math_ops.pow(
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181 | ConvertNode(node.GetSubtree(0)), 1.0f / 3.0f);
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182 | // TODO
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183 | // f: x < 0 ? -Math.Pow(-x, 1.0 / 3) : Math.Pow(x, 1.0 / 3),
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184 | // g: { var cbrt_x = x < 0 ? -Math.Pow(-x, 1.0 / 3) : Math.Pow(x, 1.0 / 3); return 1.0 / (3 * cbrt_x * cbrt_x); }
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185 | }
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186 |
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187 | if (node.Symbol is Sine) {
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188 | return tf.sin(
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189 | ConvertNode(node.GetSubtree(0)));
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190 | }
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191 |
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192 | if (node.Symbol is Cosine) {
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193 | return tf.cos(
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194 | ConvertNode(node.GetSubtree(0)));
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195 | }
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196 |
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197 | if (node.Symbol is Tangent) {
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198 | return tf.tan(
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199 | ConvertNode(node.GetSubtree(0)));
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200 | }
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201 |
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202 | if (node.Symbol is Mean) {
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203 | return tf.reduce_mean(
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204 | ConvertNode(node.GetSubtree(0)),
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205 | axis: new[] { 1 },
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206 | keepdims: true);
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207 | }
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208 |
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209 | //if (node.Symbol is StandardDeviation) {
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210 | // return tf.reduce_std(
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211 | // ConvertNode(node.GetSubtree(0)),
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212 | // axis: new [] { 1 }
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213 | // );
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214 | //}
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215 |
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216 | if (node.Symbol is Sum) {
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217 | return tf.reduce_sum(
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218 | ConvertNode(node.GetSubtree(0)),
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219 | axis: new[] { 1 },
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220 | keepdims: true);
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221 | }
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222 |
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223 | if (node.Symbol is StartSymbol) {
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224 | Tensor prediction;
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225 | if (addLinearScalingTerms) {
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226 | // scaling variables α, β are given at the beginning of the parameter vector
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227 | var alpha_arr = np.array(1.0f).reshape(1, 1);
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228 | var alpha = tf.Variable(alpha_arr, name: "alpha", dtype: DataType);
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229 | var beta_arr = np.array(0.0f).reshape(1, 1);
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230 | var beta = tf.Variable(beta_arr, name: "beta", dtype: DataType);
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231 | variables.Add(alpha);
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232 | variables.Add(beta);
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233 | var t = ConvertNode(node.GetSubtree(0));
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234 | prediction = t * alpha + beta;
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235 | } else {
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236 | prediction = ConvertNode(node.GetSubtree(0));
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237 | }
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238 |
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239 | return tf.reduce_sum(prediction, axis: new[] { 1 });
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240 | }
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241 |
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242 | throw new NotSupportedException($"Node symbol {node.Symbol} is not supported.");
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243 | }
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244 |
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245 | public static bool IsCompatible(ISymbolicExpressionTree tree) {
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246 | var containsUnknownSymbol = (
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247 | from n in tree.Root.GetSubtree(0).IterateNodesPrefix()
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248 | where
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249 | !(n.Symbol is Variable) &&
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250 | //!(n.Symbol is BinaryFactorVariable) &&
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251 | //!(n.Symbol is FactorVariable) &&
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252 | !(n.Symbol is Constant) &&
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253 | !(n.Symbol is Addition) &&
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254 | !(n.Symbol is Subtraction) &&
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255 | !(n.Symbol is Multiplication) &&
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256 | !(n.Symbol is Division) &&
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257 | !(n.Symbol is Logarithm) &&
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258 | !(n.Symbol is Exponential) &&
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259 | !(n.Symbol is SquareRoot) &&
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260 | !(n.Symbol is Square) &&
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261 | !(n.Symbol is Sine) &&
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262 | !(n.Symbol is Cosine) &&
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263 | !(n.Symbol is Tangent) &&
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264 | !(n.Symbol is HyperbolicTangent) &&
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265 | !(n.Symbol is Erf) &&
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266 | !(n.Symbol is Norm) &&
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267 | !(n.Symbol is StartSymbol) &&
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268 | !(n.Symbol is Absolute) &&
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269 | !(n.Symbol is AnalyticQuotient) &&
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270 | !(n.Symbol is Cube) &&
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271 | !(n.Symbol is CubeRoot) &&
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272 | !(n.Symbol is Mean) &&
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273 | //!(n.Symbol is StandardDeviation) &&
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274 | !(n.Symbol is Sum)
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275 | select n).Any();
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276 | return !containsUnknownSymbol;
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277 | }
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278 | }
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279 | }
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