1 | using System.Collections.Generic;
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2 | using System.Diagnostics;
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3 | using System.Linq;
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4 | using HeuristicLab.Algorithms.DataAnalysis.SymRegGrammarEnumeration.GrammarEnumeration;
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5 | using HeuristicLab.Encodings.SymbolicExpressionTreeEncoding;
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6 | using HeuristicLab.Problems.DataAnalysis;
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7 | using HeuristicLab.Problems.DataAnalysis.Symbolic;
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8 |
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9 | namespace HeuristicLab.Algorithms.DataAnalysis.SymRegGrammarEnumeration {
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10 | public class Grammar {
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11 |
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12 | public Symbol StartSymbol { get; }
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13 |
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14 | public Hasher<int> Hasher { get; }
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15 |
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16 | #region Symbols
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17 |
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18 | public IReadOnlyDictionary<Symbol, IReadOnlyList<Production>> Productions { get; }
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19 |
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20 | public NonterminalSymbol Var;
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21 | public IReadOnlyList<VariableTerminalSymbol> VarTerminals;
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22 |
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23 | public NonterminalSymbol Expr;
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24 | public NonterminalSymbol Term;
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25 | public NonterminalSymbol Factor;
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26 | public NonterminalSymbol LogFactor;
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27 | public NonterminalSymbol ExpFactor;
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28 | public NonterminalSymbol SinFactor;
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29 |
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30 | public NonterminalSymbol SimpleExpr;
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31 | public NonterminalSymbol SimpleTerm;
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32 |
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33 | public NonterminalSymbol InvExpr;
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34 | public NonterminalSymbol InvTerm;
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35 |
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36 | public TerminalSymbol Addition;
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37 | public TerminalSymbol Multiplication;
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38 | public TerminalSymbol Log;
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39 | public TerminalSymbol Exp;
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40 | public TerminalSymbol Sin;
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41 | public TerminalSymbol Inv;
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42 |
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43 | public TerminalSymbol Const;
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44 |
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45 | #endregion
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46 |
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47 | #region HL Symbols for Parsing ExpressionTrees
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48 |
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49 | private ISymbol constSy;
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50 | private ISymbol varSy;
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51 |
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52 | private ISymbol addSy;
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53 | private ISymbol mulSy;
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54 | private ISymbol logSy;
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55 | private ISymbol expSy;
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56 | private ISymbol divSy;
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57 | private ISymbol sinSy;
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58 |
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59 | private ISymbol rootSy;
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60 | private ISymbol startSy;
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61 |
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62 | private InfixExpressionFormatter infixExpressionFormatter;
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63 | #endregion
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64 |
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65 | public Grammar(string[] variables) {
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66 | #region Define Symbols
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67 | Var = new NonterminalSymbol("Var");
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68 |
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69 | Expr = new NonterminalSymbol("Expr");
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70 | Term = new NonterminalSymbol("Term");
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71 | Factor = new NonterminalSymbol("Factor");
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72 | LogFactor = new NonterminalSymbol("LogFactor");
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73 | ExpFactor = new NonterminalSymbol("ExpFactor");
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74 | SinFactor = new NonterminalSymbol("SinFactor");
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75 |
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76 | SimpleExpr = new NonterminalSymbol("SimpleExpr");
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77 | SimpleTerm = new NonterminalSymbol("SimpleTerm");
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78 |
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79 | InvExpr = new NonterminalSymbol("InvExpr");
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80 | InvTerm = new NonterminalSymbol("InvTerm");
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81 |
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82 | Addition = new TerminalSymbol("+");
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83 | Multiplication = new TerminalSymbol("*");
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84 | Log = new TerminalSymbol("log");
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85 | Exp = new TerminalSymbol("exp");
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86 | Sin = new TerminalSymbol("sin");
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87 | Inv = new TerminalSymbol("inv");
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88 |
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89 | Const = new TerminalSymbol("c");
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90 | #endregion
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91 |
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92 | #region Production rules
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93 | StartSymbol = Expr;
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94 |
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95 | Dictionary<Symbol, IReadOnlyList<Production>> productions = new Dictionary<Symbol, IReadOnlyList<Production>>();
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96 |
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97 | // Map each variable to a separate production rule of the "Var" nonterminal symbol.
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98 | VarTerminals = variables.Select(v => new VariableTerminalSymbol(v)).ToArray();
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99 | productions[Var] = VarTerminals.Select(v => new Production(v)).ToArray();
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100 |
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101 | productions[Expr] = new[] {
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102 | new Production(Const, Term, Multiplication, Expr, Addition),
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103 | new Production(Const, Term, Multiplication, Const, Addition)
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104 | };
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105 |
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106 | productions[Term] = new[] {
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107 | new Production(Factor, Term, Multiplication),
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108 | new Production(Factor),
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109 | new Production(InvExpr, Inv)
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110 | };
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111 |
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112 | productions[Factor] = new[] {
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113 | new Production(Var),
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114 | new Production(LogFactor),
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115 | new Production(ExpFactor),
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116 | new Production(SinFactor),
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117 | };
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118 |
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119 | productions[LogFactor] = new[] { new Production(SimpleExpr, Log) };
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120 | productions[ExpFactor] = new[] { new Production(Const, SimpleTerm, Multiplication, Exp) };
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121 | productions[SinFactor] = new[] { new Production(SimpleExpr, Sin) };
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122 |
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123 | productions[SimpleExpr] = new[] {
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124 | new Production(Const, SimpleTerm, Multiplication, SimpleExpr, Addition),
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125 | new Production(Const, SimpleTerm, Multiplication, Const, Addition)
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126 | };
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127 |
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128 | productions[SimpleTerm] = new[] {
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129 | new Production(Var, SimpleTerm, Multiplication),
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130 | new Production(Var)
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131 | };
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132 |
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133 | productions[InvExpr] = new[] {
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134 | new Production(Const, InvTerm, Multiplication, InvExpr, Addition),
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135 | new Production(Const, InvTerm, Multiplication, Const, Addition)
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136 | };
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137 |
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138 | productions[InvTerm] = new[] {
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139 | new Production(Factor, InvTerm, Multiplication),
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140 | new Production(Factor)
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141 | };
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142 |
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143 | Productions = productions;
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144 | #endregion
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145 |
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146 | #region Parsing to SymbolicExpressionTree
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147 | var symbolicExpressionGrammar = new TypeCoherentExpressionGrammar();
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148 | symbolicExpressionGrammar.ConfigureAsDefaultRegressionGrammar();
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149 |
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150 | constSy = symbolicExpressionGrammar.Symbols.OfType<Constant>().First();
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151 | varSy = symbolicExpressionGrammar.Symbols.OfType<Variable>().First();
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152 | addSy = symbolicExpressionGrammar.Symbols.OfType<Addition>().First();
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153 | mulSy = symbolicExpressionGrammar.Symbols.OfType<Multiplication>().First();
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154 | logSy = symbolicExpressionGrammar.Symbols.OfType<Logarithm>().First();
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155 | expSy = symbolicExpressionGrammar.Symbols.OfType<Exponential>().First();
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156 | divSy = symbolicExpressionGrammar.Symbols.OfType<Division>().First();
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157 | sinSy = symbolicExpressionGrammar.Symbols.OfType<Sine>().First();
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158 |
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159 | rootSy = symbolicExpressionGrammar.Symbols.OfType<ProgramRootSymbol>().First();
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160 | startSy = symbolicExpressionGrammar.Symbols.OfType<StartSymbol>().First();
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161 |
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162 | infixExpressionFormatter = new InfixExpressionFormatter();
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163 | #endregion
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164 |
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165 | Hasher = new IntHasher(this);
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166 | }
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167 |
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168 | public int GetComplexity(SymbolString s) {
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169 | int c = 0;
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170 | int length = s.Count();
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171 | for (int i = 0; i < length; i++) {
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172 | if (s[i] is NonterminalSymbol || s[i] is VariableTerminalSymbol) c++;
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173 | }
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174 | return c;
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175 | }
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176 |
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177 | public double EvaluatePhrase(SymbolString s, IRegressionProblemData problemData, bool optimizeConstants) {
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178 | // Create sentences without Expression symbols.
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179 | Symbol[] sEval = new Symbol[s.Count()];
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180 |
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181 | for (int i = 0; i < sEval.Length; i++) {
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182 | Symbol currSym = s[i];
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183 | if (currSym is NonterminalSymbol && currSym != Expr)
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184 | return 0.0;
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185 |
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186 | if (currSym == Expr) {
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187 | sEval[i] = Const;
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188 | } else {
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189 | sEval[i] = currSym;
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190 | }
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191 | }
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192 |
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193 | SymbolicExpressionTree tree = ParseSymbolicExpressionTree(new SymbolString(sEval));
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194 | double r2 = RSquaredEvaluator.Evaluate(problemData, tree, optimizeConstants);
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195 |
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196 | return r2;
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197 | }
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198 |
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199 | #region Parse to SymbolicExpressionTree
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200 |
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201 | public string ToInfixString(SymbolString sentence) {
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202 | Debug.Assert(sentence.Any(), "Trying to evaluate empty sentence!");
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203 | Debug.Assert(sentence.All(s => s is TerminalSymbol), "Trying to evaluate symbol sequence with nonterminalsymbols!");
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204 |
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205 | return infixExpressionFormatter.Format(ParseSymbolicExpressionTree(sentence));
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206 | }
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207 |
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208 | public SymbolicExpressionTree ParseSymbolicExpressionTree(SymbolString sentence) {
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209 | Debug.Assert(sentence.Any(), "Trying to evaluate empty sentence!");
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210 | Debug.Assert(sentence.All(s => s is TerminalSymbol), "Trying to evaluate symbol sequence with nonterminalsymbols!");
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211 |
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212 | var rootNode = rootSy.CreateTreeNode();
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213 | var startNode = startSy.CreateTreeNode();
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214 | rootNode.AddSubtree(startNode);
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215 |
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216 | Stack<TerminalSymbol> parseStack = new Stack<TerminalSymbol>(sentence.OfType<TerminalSymbol>());
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217 | startNode.AddSubtree(ParseSymbolicExpressionTree(parseStack));
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218 |
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219 | return new SymbolicExpressionTree(rootNode);
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220 | }
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221 |
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222 | public ISymbolicExpressionTreeNode ParseSymbolicExpressionTree(Stack<TerminalSymbol> parseStack) {
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223 | TerminalSymbol currentSymbol = parseStack.Pop();
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224 |
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225 | ISymbolicExpressionTreeNode parsedSubTree = null;
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226 |
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227 | if (currentSymbol == Addition) {
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228 | parsedSubTree = addSy.CreateTreeNode();
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229 | ISymbolicExpressionTreeNode rightSubtree = ParseSymbolicExpressionTree(parseStack);
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230 | if (rightSubtree is ConstantTreeNode) {
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231 | ((ConstantTreeNode)rightSubtree).Value = 0.0;
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232 | }
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233 | parsedSubTree.AddSubtree(rightSubtree); // left part
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234 |
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235 | ISymbolicExpressionTreeNode leftSubtree = ParseSymbolicExpressionTree(parseStack);
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236 | if (leftSubtree is ConstantTreeNode) {
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237 | ((ConstantTreeNode)leftSubtree).Value = 0.0;
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238 | }
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239 | parsedSubTree.AddSubtree(leftSubtree); // right part
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240 |
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241 | } else if (currentSymbol == Multiplication) {
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242 | parsedSubTree = mulSy.CreateTreeNode();
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243 | parsedSubTree.AddSubtree(ParseSymbolicExpressionTree(parseStack)); // left part
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244 | parsedSubTree.AddSubtree(ParseSymbolicExpressionTree(parseStack)); // right part
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245 |
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246 | } else if (currentSymbol == Log) {
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247 | parsedSubTree = logSy.CreateTreeNode();
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248 | parsedSubTree.AddSubtree(ParseSymbolicExpressionTree(parseStack));
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249 |
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250 | } else if (currentSymbol == Exp) {
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251 | parsedSubTree = expSy.CreateTreeNode();
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252 | parsedSubTree.AddSubtree(ParseSymbolicExpressionTree(parseStack));
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253 |
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254 | } else if (currentSymbol == Sin) {
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255 | parsedSubTree = sinSy.CreateTreeNode();
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256 | parsedSubTree.AddSubtree(ParseSymbolicExpressionTree(parseStack));
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257 |
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258 | } else if (currentSymbol == Inv) {
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259 | parsedSubTree = divSy.CreateTreeNode();
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260 | ConstantTreeNode dividend = (ConstantTreeNode)constSy.CreateTreeNode();
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261 | dividend.Value = 1.0;
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262 | parsedSubTree.AddSubtree(dividend);
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263 | parsedSubTree.AddSubtree(ParseSymbolicExpressionTree(parseStack));
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264 |
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265 | } else if (currentSymbol == Const) {
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266 | ConstantTreeNode constNode = (ConstantTreeNode)constSy.CreateTreeNode();
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267 | constNode.Value = 1.0;
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268 | parsedSubTree = constNode;
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269 |
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270 | } else if (currentSymbol is VariableTerminalSymbol) {
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271 | VariableTreeNode varNode = (VariableTreeNode)varSy.CreateTreeNode();
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272 | varNode.Weight = 1.0;
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273 | varNode.VariableName = currentSymbol.StringRepresentation;
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274 | parsedSubTree = varNode;
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275 | }
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276 |
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277 | Debug.Assert(parsedSubTree != null);
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278 | return parsedSubTree;
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279 | }
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280 | #endregion
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281 | }
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282 | }
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