1 | using System;
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2 | using System.Collections.Generic;
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3 | using System.Diagnostics;
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4 | using System.Linq;
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5 | using HeuristicLab.Algorithms.DataAnalysis.SymRegGrammarEnumeration.GrammarEnumeration;
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6 | using HeuristicLab.Common;
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7 | using HeuristicLab.Encodings.SymbolicExpressionTreeEncoding;
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8 | using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
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9 | using HeuristicLab.Problems.DataAnalysis;
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10 | using HeuristicLab.Problems.DataAnalysis.Symbolic;
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11 |
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12 | namespace HeuristicLab.Algorithms.DataAnalysis.SymRegGrammarEnumeration {
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13 | public enum GrammarRule {
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14 | MultipleTerms,
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15 | MultipleFactors,
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16 | InverseTerm,
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17 | Logarithm,
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18 | Exponentiation,
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19 | Sine
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20 | }
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21 |
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22 | [StorableClass(StorableClassType.AllFieldsAndAllProperties)]
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23 | public class Grammar : DeepCloneable {
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24 | public Symbol StartSymbol { get; private set; }
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25 |
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26 | public Hasher<int> Hasher { get; private set; }
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27 |
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28 | #region Symbols
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29 |
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30 | public IReadOnlyDictionary<Symbol, IReadOnlyList<SymbolList>> Productions { get; private set; }
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31 |
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32 | public NonterminalSymbol Var;
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33 | public IReadOnlyList<VariableTerminalSymbol> VarTerminals;
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34 |
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35 | public NonterminalSymbol Expr;
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36 | public NonterminalSymbol Term;
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37 | public NonterminalSymbol Factor;
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38 | public NonterminalSymbol LogFactor;
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39 | public NonterminalSymbol ExpFactor;
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40 | public NonterminalSymbol SinFactor;
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41 |
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42 | public NonterminalSymbol SimpleExpr;
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43 | public NonterminalSymbol SimpleTerm;
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44 |
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45 | public NonterminalSymbol InvExpr;
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46 | public NonterminalSymbol InvTerm;
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47 |
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48 | public TerminalSymbol Addition;
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49 | public TerminalSymbol Multiplication;
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50 | public TerminalSymbol Log;
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51 | public TerminalSymbol Exp;
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52 | public TerminalSymbol Sin;
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53 | public TerminalSymbol Inv;
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54 |
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55 | public TerminalSymbol Const;
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56 |
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57 | #endregion
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58 |
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59 | #region HL Symbols for Parsing ExpressionTrees
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60 |
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61 | private ISymbol constSy;
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62 | private ISymbol varSy;
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63 |
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64 | private ISymbol addSy;
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65 | private ISymbol mulSy;
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66 | private ISymbol logSy;
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67 | private ISymbol expSy;
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68 | private ISymbol divSy;
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69 | private ISymbol sinSy;
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70 |
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71 | private ISymbol rootSy;
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72 | private ISymbol startSy;
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73 |
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74 | private InfixExpressionFormatter infixExpressionFormatter;
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75 | #endregion
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76 |
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77 | public Grammar(string[] variables) : this(variables, Enum.GetValues(typeof(GrammarRule)).Cast<GrammarRule>()) { }
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78 |
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79 | [StorableConstructor]
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80 | protected Grammar(bool deserializing) {
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81 | InitTreeParser();
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82 | }
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83 |
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84 | protected Grammar(Grammar original, Cloner cloner) : base(original, cloner) {
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85 | infixExpressionFormatter = cloner.Clone(original.infixExpressionFormatter);
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86 |
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87 | Productions = original.Productions.ToDictionary(x => cloner.Clone(x.Key), x => (IReadOnlyList<SymbolList>)x.Value.Select(cloner.Clone).ToList());
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88 | VarTerminals = original.VarTerminals.Select(cloner.Clone).ToList();
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89 |
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90 | Var = (NonterminalSymbol)cloner.Clone(original.Var);
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91 | Expr = (NonterminalSymbol)cloner.Clone(original.Expr);
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92 | Term = (NonterminalSymbol)cloner.Clone(original.Term);
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93 | Factor = (NonterminalSymbol)cloner.Clone(original.Factor);
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94 | LogFactor = (NonterminalSymbol)cloner.Clone(original.LogFactor);
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95 | ExpFactor = (NonterminalSymbol)cloner.Clone(original.ExpFactor);
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96 | SinFactor = (NonterminalSymbol)cloner.Clone(original.SinFactor);
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97 | SimpleExpr = (NonterminalSymbol)cloner.Clone(original.SimpleExpr);
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98 | SimpleTerm = (NonterminalSymbol)cloner.Clone(original.SimpleTerm);
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99 | InvExpr = (NonterminalSymbol)cloner.Clone(original.InvExpr);
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100 | InvTerm = (NonterminalSymbol)cloner.Clone(original.InvTerm);
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101 |
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102 | Addition = (TerminalSymbol)cloner.Clone(original.Addition);
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103 | Multiplication = (TerminalSymbol)cloner.Clone(original.Multiplication);
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104 | Log = (TerminalSymbol)cloner.Clone(original.Log);
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105 | Exp = (TerminalSymbol)cloner.Clone(original.Exp);
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106 | Sin = (TerminalSymbol)cloner.Clone(original.Sin);
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107 | Inv = (TerminalSymbol)cloner.Clone(original.Inv);
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108 | Const = (TerminalSymbol)cloner.Clone(original.Const);
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109 |
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110 | StartSymbol = Expr;
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111 | Hasher = cloner.Clone(original.Hasher);
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112 |
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113 | InitTreeParser(); // easier this way (and less typing)
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114 | }
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115 |
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116 | private void InitProductions(string[] variables, IEnumerable<GrammarRule> includedRules) {
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117 | #region Define Symbols
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118 | Var = new NonterminalSymbol("Var");
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119 |
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120 | Expr = new NonterminalSymbol("Expr");
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121 | Term = new NonterminalSymbol("Term");
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122 | Factor = new NonterminalSymbol("Factor");
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123 | LogFactor = new NonterminalSymbol("LogFactor");
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124 | ExpFactor = new NonterminalSymbol("ExpFactor");
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125 | SinFactor = new NonterminalSymbol("SinFactor");
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126 |
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127 | SimpleExpr = new NonterminalSymbol("SimpleExpr");
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128 | SimpleTerm = new NonterminalSymbol("SimpleTerm");
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129 |
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130 | InvExpr = new NonterminalSymbol("InvExpr");
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131 | InvTerm = new NonterminalSymbol("InvTerm");
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132 |
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133 | Addition = new TerminalSymbol("+");
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134 | Multiplication = new TerminalSymbol("*");
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135 | Log = new TerminalSymbol("log");
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136 | Exp = new TerminalSymbol("exp");
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137 | Sin = new TerminalSymbol("sin");
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138 | Inv = new TerminalSymbol("inv");
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139 |
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140 | Const = new TerminalSymbol("c");
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141 | #endregion
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142 |
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143 | #region Production rules
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144 | StartSymbol = Expr;
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145 |
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146 | Dictionary<Symbol, IReadOnlyList<SymbolList>> productions = new Dictionary<Symbol, IReadOnlyList<SymbolList>>();
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147 |
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148 | // Map each variable to a separate production rule of the "Var" nonterminal symbol.
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149 | VarTerminals = variables.Select(v => new VariableTerminalSymbol(v)).ToArray();
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150 | productions[Var] = VarTerminals.Select(v => new SymbolList(v)).ToArray();
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151 |
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152 | // Expression Grammar Rules
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153 | var exprProductions = new List<SymbolList>();
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154 | if (includedRules.Contains(GrammarRule.MultipleTerms))
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155 | exprProductions.Add(new SymbolList(Const, Term, Multiplication, Expr, Addition));
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156 |
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157 | exprProductions.Add(new SymbolList(Const, Term, Multiplication, Const, Addition));
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158 | productions[Expr] = exprProductions.ToArray();
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159 |
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160 | // Term Grammar Rules
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161 | var termProductions = new List<SymbolList>();
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162 | if (includedRules.Contains(GrammarRule.MultipleFactors))
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163 | termProductions.Add(new SymbolList(Factor, Term, Multiplication));
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164 | if (includedRules.Contains(GrammarRule.InverseTerm))
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165 | termProductions.Add(new SymbolList(InvExpr, Inv));
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166 | termProductions.Add(new SymbolList(Factor));
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167 | productions[Term] = termProductions.ToArray();
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168 |
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169 | // Factor Grammar Rules
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170 | var factorProductions = new List<SymbolList>();
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171 | factorProductions.Add(new SymbolList(Var));
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172 | if (includedRules.Contains(GrammarRule.Logarithm))
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173 | factorProductions.Add(new SymbolList(LogFactor));
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174 | if (includedRules.Contains(GrammarRule.Exponentiation))
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175 | factorProductions.Add(new SymbolList(ExpFactor));
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176 | if (includedRules.Contains(GrammarRule.Sine))
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177 | factorProductions.Add(new SymbolList(SinFactor));
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178 | productions[Factor] = factorProductions.ToArray();
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179 |
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180 | productions[LogFactor] = new[] { new SymbolList(SimpleExpr, Log) };
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181 | productions[ExpFactor] = new[] { new SymbolList(Const, SimpleTerm, Multiplication, Exp) };
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182 | productions[SinFactor] = new[] { new SymbolList(SimpleExpr, Sin) };
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183 |
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184 | productions[SimpleExpr] = new[] {
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185 | new SymbolList(Const, SimpleTerm, Multiplication, SimpleExpr, Addition),
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186 | new SymbolList(Const, SimpleTerm, Multiplication, Const, Addition)
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187 | };
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188 |
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189 | productions[SimpleTerm] = new[] {
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190 | new SymbolList(Var, SimpleTerm, Multiplication),
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191 | new SymbolList(Var)
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192 | };
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193 |
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194 | productions[InvExpr] = new[] {
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195 | new SymbolList(Const, InvTerm, Multiplication, InvExpr, Addition),
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196 | new SymbolList(Const, InvTerm, Multiplication, Const, Addition)
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197 | };
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198 |
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199 | productions[InvTerm] = new[] {
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200 | new SymbolList(Factor, InvTerm, Multiplication),
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201 | new SymbolList(Factor)
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202 | };
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203 |
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204 | Productions = productions;
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205 | #endregion
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206 | }
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207 |
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208 | private void InitTreeParser() {
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209 | #region Parsing to SymbolicExpressionTree
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210 | var symbolicExpressionGrammar = new TypeCoherentExpressionGrammar();
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211 | symbolicExpressionGrammar.ConfigureAsDefaultRegressionGrammar();
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212 |
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213 | constSy = symbolicExpressionGrammar.Symbols.OfType<Constant>().First();
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214 | varSy = symbolicExpressionGrammar.Symbols.OfType<Variable>().First();
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215 | addSy = symbolicExpressionGrammar.Symbols.OfType<Addition>().First();
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216 | mulSy = symbolicExpressionGrammar.Symbols.OfType<Multiplication>().First();
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217 | logSy = symbolicExpressionGrammar.Symbols.OfType<Logarithm>().First();
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218 | expSy = symbolicExpressionGrammar.Symbols.OfType<Exponential>().First();
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219 | divSy = symbolicExpressionGrammar.Symbols.OfType<Division>().First();
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220 | sinSy = symbolicExpressionGrammar.Symbols.OfType<Sine>().First();
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221 |
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222 | rootSy = symbolicExpressionGrammar.Symbols.OfType<ProgramRootSymbol>().First();
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223 | startSy = symbolicExpressionGrammar.Symbols.OfType<StartSymbol>().First();
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224 |
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225 | infixExpressionFormatter = new InfixExpressionFormatter();
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226 | #endregion
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227 | }
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228 |
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229 | public Grammar(string[] variables, IEnumerable<GrammarRule> includedRules) {
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230 | InitProductions(variables, includedRules);
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231 | InitTreeParser();
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232 |
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233 | Hasher = new IntHasher(this);
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234 | }
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235 |
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236 | // returns the maximum achievable sentence length below the maximum complexity
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237 | public int GetMaxSentenceLength(int maxComplexity) {
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238 | SymbolList s = new SymbolList(StartSymbol);
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239 |
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240 | while (!s.IsSentence() && s.Complexity <= maxComplexity) {
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241 | int expandedSymbolIndex = s.NextNonterminalIndex();
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242 | NonterminalSymbol expandedSymbol = (NonterminalSymbol)s[expandedSymbolIndex];
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243 |
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244 | var productions = Productions[expandedSymbol];
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245 | var longestProduction = productions // Find production with most terminal symbols to expand as much as possible...
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246 | .OrderBy(x => x.TerminalSymbolCount) // but with lowest complexity/nonterminal count to keep complexity low.
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247 | .ThenByDescending(x => x.NonTerminalSymbolCount)
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248 | .First();
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249 |
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250 | s = s.DerivePhrase(expandedSymbolIndex, longestProduction);
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251 | }
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252 | return s.Count;
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253 | }
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254 |
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255 | public double EvaluatePhrase(SymbolList s, IRegressionProblemData problemData, bool optimizeConstants, int iterations) {
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256 | SymbolicExpressionTree tree = ParseSymbolicExpressionTree(s);
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257 |
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258 | return RSquaredEvaluator.Evaluate(problemData, tree, optimizeConstants, iterations);
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259 | }
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260 |
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261 | #region Parse to SymbolicExpressionTree
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262 |
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263 | public string ToInfixString(SymbolList sentence) {
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264 | Debug.Assert(sentence.Any(), "Trying to evaluate empty sentence!");
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265 | Debug.Assert(sentence.All(s => s is TerminalSymbol), "Trying to evaluate symbol sequence with nonterminalsymbols!");
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266 |
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267 | return infixExpressionFormatter.Format(ParseSymbolicExpressionTree(sentence));
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268 | }
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269 |
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270 | public SymbolicExpressionTree ParseSymbolicExpressionTree(SymbolList sentence) {
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271 | Debug.Assert(sentence.Any(), "Trying to evaluate empty sentence!");
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272 |
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273 | var rootNode = rootSy.CreateTreeNode();
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274 | var startNode = startSy.CreateTreeNode();
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275 | rootNode.AddSubtree(startNode);
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276 |
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277 | Stack<Symbol> parseStack = new Stack<Symbol>(sentence);
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278 | startNode.AddSubtree(ParseSymbolicExpressionTree(parseStack));
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279 |
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280 | return new SymbolicExpressionTree(rootNode);
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281 | }
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282 |
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283 | public ISymbolicExpressionTreeNode ParseSymbolicExpressionTree(Stack<Symbol> parseStack) {
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284 | Symbol currentSymbol = parseStack.Pop();
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285 |
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286 | ISymbolicExpressionTreeNode parsedSubTree = null;
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287 |
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288 | if (currentSymbol == Addition) {
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289 | parsedSubTree = addSy.CreateTreeNode();
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290 | ISymbolicExpressionTreeNode rightSubtree = ParseSymbolicExpressionTree(parseStack);
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291 | if (rightSubtree is ConstantTreeNode) {
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292 | ((ConstantTreeNode)rightSubtree).Value = 0.0;
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293 | }
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294 | parsedSubTree.AddSubtree(rightSubtree); // left part
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295 |
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296 | ISymbolicExpressionTreeNode leftSubtree = ParseSymbolicExpressionTree(parseStack);
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297 | if (leftSubtree is ConstantTreeNode) {
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298 | ((ConstantTreeNode)leftSubtree).Value = 0.0;
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299 | }
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300 | parsedSubTree.AddSubtree(leftSubtree); // right part
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301 |
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302 | } else if (currentSymbol == Multiplication) {
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303 | parsedSubTree = mulSy.CreateTreeNode();
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304 | parsedSubTree.AddSubtree(ParseSymbolicExpressionTree(parseStack)); // left part
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305 | parsedSubTree.AddSubtree(ParseSymbolicExpressionTree(parseStack)); // right part
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306 |
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307 | } else if (currentSymbol == Log) {
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308 | parsedSubTree = logSy.CreateTreeNode();
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309 | parsedSubTree.AddSubtree(ParseSymbolicExpressionTree(parseStack));
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310 |
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311 | } else if (currentSymbol == Exp) {
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312 | parsedSubTree = expSy.CreateTreeNode();
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313 | parsedSubTree.AddSubtree(ParseSymbolicExpressionTree(parseStack));
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314 |
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315 | } else if (currentSymbol == Sin) {
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316 | parsedSubTree = sinSy.CreateTreeNode();
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317 | parsedSubTree.AddSubtree(ParseSymbolicExpressionTree(parseStack));
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318 |
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319 | } else if (currentSymbol == Inv) {
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320 | parsedSubTree = divSy.CreateTreeNode();
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321 | ConstantTreeNode dividend = (ConstantTreeNode)constSy.CreateTreeNode();
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322 | dividend.Value = 1.0;
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323 | parsedSubTree.AddSubtree(dividend);
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324 | parsedSubTree.AddSubtree(ParseSymbolicExpressionTree(parseStack));
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325 |
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326 | } else if (currentSymbol == Const) {
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327 | ConstantTreeNode constNode = (ConstantTreeNode)constSy.CreateTreeNode();
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328 | constNode.Value = 1.0;
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329 | parsedSubTree = constNode;
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330 |
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331 | } else if (currentSymbol is VariableTerminalSymbol) {
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332 | VariableTreeNode varNode = (VariableTreeNode)varSy.CreateTreeNode();
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333 | varNode.Weight = 1.0;
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334 | varNode.VariableName = currentSymbol.StringRepresentation;
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335 | parsedSubTree = varNode;
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336 |
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337 | } else if (currentSymbol is NonterminalSymbol) {
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338 | ConstantTreeNode constNode = (ConstantTreeNode)constSy.CreateTreeNode();
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339 | constNode.Value = 0.0;
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340 | parsedSubTree = constNode;
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341 | }
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342 |
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343 | Debug.Assert(parsedSubTree != null);
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344 | return parsedSubTree;
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345 | }
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346 | #endregion
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347 |
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348 | #region abstract DeepCloneable methods
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349 | public override IDeepCloneable Clone(Cloner cloner) {
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350 | return new Grammar(this, cloner);
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351 | }
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352 | #endregion
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353 | }
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354 | }
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