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source: stable/HeuristicLab.Problems.DataAnalysis.Symbolic/3.4/Formatters/SymbolicDataAnalysisExpressionCSharpFormatter.cs @ 14821

Last change on this file since 14821 was 14186, checked in by swagner, 8 years ago

#2526: Updated year of copyrights in license headers

File size: 9.4 KB
RevLine 
[12434]1#region License Information
2/* HeuristicLab
[14186]3 * Copyright (C) 2002-2016 Heuristic and Evolutionary Algorithms Laboratory (HEAL)
[12434]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;
23using System.Collections.Generic;
24using System.Globalization;
25using System.Linq;
26using System.Text;
27using HeuristicLab.Common;
28using HeuristicLab.Core;
29using HeuristicLab.Encodings.SymbolicExpressionTreeEncoding;
30using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
31
32namespace HeuristicLab.Problems.DataAnalysis.Symbolic {
33  [Item("C# Symbolic Expression Tree Formatter", "A string formatter that converts symbolic expression trees to C# code.")]
34  [StorableClass]
35  public sealed class CSharpSymbolicExpressionTreeStringFormatter : NamedItem, ISymbolicExpressionTreeStringFormatter {
36    [StorableConstructor]
37    private CSharpSymbolicExpressionTreeStringFormatter(bool deserializing) : base(deserializing) { }
38    private CSharpSymbolicExpressionTreeStringFormatter(CSharpSymbolicExpressionTreeStringFormatter original, Cloner cloner) : base(original, cloner) { }
39    public CSharpSymbolicExpressionTreeStringFormatter()
40      : base() {
41      Name = ItemName;
42      Description = ItemDescription;
43    }
44    public override IDeepCloneable Clone(Cloner cloner) {
45      return new CSharpSymbolicExpressionTreeStringFormatter(this, cloner);
46    }
47
48    public string Format(ISymbolicExpressionTree symbolicExpressionTree) {
49      // skip root and start symbols
50      StringBuilder strBuilder = new StringBuilder();
51      GenerateHeader(strBuilder, symbolicExpressionTree);
52      FormatRecursively(symbolicExpressionTree.Root.GetSubtree(0).GetSubtree(0), strBuilder);
53      GenerateFooter(strBuilder);
54      return strBuilder.ToString();
55    }
56
57    private void FormatRecursively(ISymbolicExpressionTreeNode node, StringBuilder strBuilder) {
[13047]58      // TODO: adapt to interpreter semantics. The HL interpreter also allows Boolean operations on reals
[12434]59      if (node.Subtrees.Any()) {
60        if (node.Symbol is Addition) {
61          FormatOperator(node, "+", strBuilder);
62        } else if (node.Symbol is And) {
63          FormatOperator(node, "&&", strBuilder);
64        } else if (node.Symbol is Average) {
65          FormatFunction(node, "Average", strBuilder);
66        } else if (node.Symbol is Cosine) {
67          FormatFunction(node, "Math.Cos", strBuilder);
68        } else if (node.Symbol is Division) {
69          FormatDivision(node, strBuilder);
70        } else if (node.Symbol is Exponential) {
71          FormatFunction(node, "Math.Exp", strBuilder);
72        } else if (node.Symbol is GreaterThan) {
73          FormatOperator(node, ">", strBuilder);
74        } else if (node.Symbol is IfThenElse) {
75          FormatFunction(node, "EvaluateIf", strBuilder);
76        } else if (node.Symbol is LessThan) {
77          FormatOperator(node, "<", strBuilder);
78        } else if (node.Symbol is Logarithm) {
79          FormatFunction(node, "Math.Log", strBuilder);
80        } else if (node.Symbol is Multiplication) {
81          FormatOperator(node, "*", strBuilder);
82        } else if (node.Symbol is Not) {
83          FormatOperator(node, "!", strBuilder);
84        } else if (node.Symbol is Or) {
85          FormatOperator(node, "||", strBuilder);
[13047]86        } else if (node.Symbol is Xor) {
87          FormatOperator(node, "^", strBuilder);
[12434]88        } else if (node.Symbol is Sine) {
89          FormatFunction(node, "Math.Sin", strBuilder);
90        } else if (node.Symbol is Subtraction) {
[13240]91          FormatSubtraction(node, strBuilder);
[12434]92        } else if (node.Symbol is Tangent) {
93          FormatFunction(node, "Math.Tan", strBuilder);
94        } else if (node.Symbol is Square) {
95          FormatSquare(node, strBuilder);
96        } else if (node.Symbol is SquareRoot) {
97          FormatFunction(node, "Math.Sqrt", strBuilder);
98        } else if (node.Symbol is Power) {
99          FormatFunction(node, "Math.Pow", strBuilder);
100        } else if (node.Symbol is Root) {
101          FormatRoot(node, strBuilder);
102        } else {
103          throw new NotSupportedException("Formatting of symbol: " + node.Symbol + " not supported for C# symbolic expression tree formatter.");
104        }
105      } else {
106        if (node is VariableTreeNode) {
107          var varNode = node as VariableTreeNode;
108          strBuilder.AppendFormat("{0} * {1}", varNode.VariableName, varNode.Weight.ToString("g17", CultureInfo.InvariantCulture));
109        } else if (node is ConstantTreeNode) {
110          var constNode = node as ConstantTreeNode;
111          strBuilder.Append(constNode.Value.ToString("g17", CultureInfo.InvariantCulture));
112        } else {
113          throw new NotSupportedException("Formatting of symbol: " + node.Symbol + " not supported for C# symbolic expression tree formatter.");
114        }
115      }
116    }
117
118    private void FormatSquare(ISymbolicExpressionTreeNode node, StringBuilder strBuilder) {
119      strBuilder.Append("Math.Pow(");
120      FormatRecursively(node.GetSubtree(0), strBuilder);
121      strBuilder.Append(", 2)");
122    }
123
124    private void FormatRoot(ISymbolicExpressionTreeNode node, StringBuilder strBuilder) {
125      strBuilder.Append("Math.Pow(");
126      FormatRecursively(node.GetSubtree(0), strBuilder);
127      strBuilder.Append(", 1.0 / (");
128      FormatRecursively(node.GetSubtree(1), strBuilder);
129      strBuilder.Append("))");
130    }
131
132    private void FormatDivision(ISymbolicExpressionTreeNode node, StringBuilder strBuilder) {
133      if (node.SubtreeCount == 1) {
134        strBuilder.Append("1.0 / ");
135        FormatRecursively(node.GetSubtree(0), strBuilder);
136      } else {
137        FormatRecursively(node.GetSubtree(0), strBuilder);
138        strBuilder.Append("/ (");
139        for (int i = 1; i < node.SubtreeCount; i++) {
140          if (i > 1) strBuilder.Append(" * ");
141          FormatRecursively(node.GetSubtree(i), strBuilder);
142        }
143        strBuilder.Append(")");
144      }
145    }
146
[13240]147    private void FormatSubtraction(ISymbolicExpressionTreeNode node, StringBuilder strBuilder) {
148      if (node.SubtreeCount == 1) {
149        strBuilder.Append("-");
150        FormatRecursively(node.GetSubtree(0), strBuilder);
151        return;
152      }
153      //Default case: more than 1 child
154      FormatOperator(node, "-", strBuilder);
155    }
156
[12434]157    private void FormatOperator(ISymbolicExpressionTreeNode node, string symbol, StringBuilder strBuilder) {
158      strBuilder.Append("(");
159      foreach (var child in node.Subtrees) {
160        FormatRecursively(child, strBuilder);
161        if (child != node.Subtrees.Last())
162          strBuilder.Append(" " + symbol + " ");
163      }
164      strBuilder.Append(")");
165    }
166
167    private void FormatFunction(ISymbolicExpressionTreeNode node, string function, StringBuilder strBuilder) {
168      strBuilder.Append(function + "(");
169      foreach (var child in node.Subtrees) {
170        FormatRecursively(child, strBuilder);
171        if (child != node.Subtrees.Last())
172          strBuilder.Append(", ");
173      }
174      strBuilder.Append(")");
175    }
176
177    private void GenerateHeader(StringBuilder strBuilder, ISymbolicExpressionTree symbolicExpressionTree) {
178      strBuilder.AppendLine("using System;");
179      strBuilder.AppendLine("using System.Linq;" + Environment.NewLine);
180      strBuilder.AppendLine("namespace HeuristicLab.Models {");
181      strBuilder.AppendLine("public static class Model {");
182      GenerateAverageSource(strBuilder);
183      GenerateIfThenElseSource(strBuilder);
184      strBuilder.Append(Environment.NewLine + "public static double Evaluate (");
185
186      HashSet<string> varNames = new HashSet<string>();
187      foreach (var node in symbolicExpressionTree.IterateNodesPostfix().Where(x => x is VariableTreeNode)) {
188        varNames.Add(((VariableTreeNode)node).VariableName);
189      }
190
[13240]191      var orderedNames = varNames.OrderBy(n => n, new NaturalStringComparer()).Select(n => "double " + n);
[12652]192      strBuilder.Append(string.Join(", ", orderedNames));
193
[12434]194      strBuilder.AppendLine(") {");
195      strBuilder.Append("double result = ");
196    }
197
198    private void GenerateFooter(StringBuilder strBuilder) {
199      strBuilder.AppendLine(";");
200      strBuilder.AppendLine("return result;");
201      strBuilder.AppendLine("}");
202      strBuilder.AppendLine("}");
203      strBuilder.AppendLine("}");
204    }
205
206    private void GenerateAverageSource(StringBuilder strBuilder) {
207      strBuilder.AppendLine("private static double Average(params double[] values) {");
208      strBuilder.AppendLine("  return values.Average();");
209      strBuilder.AppendLine("}");
210    }
211
212    private void GenerateIfThenElseSource(StringBuilder strBuilder) {
213      strBuilder.AppendLine("private static double EvaluateIf(bool condition, double then, double @else) {");
214      strBuilder.AppendLine("   return condition ? then : @else;");
215      strBuilder.AppendLine("}");
216    }
217  }
218}
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