Index: stable/HeuristicLab.Problems.DataAnalysis.Symbolic/3.4/Formatters/SymbolicDataAnalysisExpressionCSharpFormatter.cs
===================================================================
--- stable/HeuristicLab.Problems.DataAnalysis.Symbolic/3.4/Formatters/SymbolicDataAnalysisExpressionCSharpFormatter.cs	(revision 12652)
+++ stable/HeuristicLab.Problems.DataAnalysis.Symbolic/3.4/Formatters/SymbolicDataAnalysisExpressionCSharpFormatter.cs	(revision 12652)
@@ -0,0 +1,205 @@
+﻿#region License Information
+/* HeuristicLab
+ * Copyright (C) 2002-2015 Heuristic and Evolutionary Algorithms Laboratory (HEAL)
+ *
+ * This file is part of HeuristicLab.
+ *
+ * HeuristicLab is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * HeuristicLab is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with HeuristicLab. If not, see <http://www.gnu.org/licenses/>.
+ */
+#endregion
+
+using System;
+using System.Collections.Generic;
+using System.Globalization;
+using System.Linq;
+using System.Text;
+using HeuristicLab.Common;
+using HeuristicLab.Core;
+using HeuristicLab.Encodings.SymbolicExpressionTreeEncoding;
+using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
+
+namespace HeuristicLab.Problems.DataAnalysis.Symbolic {
+  [Item("C# Symbolic Expression Tree Formatter", "A string formatter that converts symbolic expression trees to C# code.")]
+  [StorableClass]
+  public sealed class CSharpSymbolicExpressionTreeStringFormatter : NamedItem, ISymbolicExpressionTreeStringFormatter {
+    [StorableConstructor]
+    private CSharpSymbolicExpressionTreeStringFormatter(bool deserializing) : base(deserializing) { }
+    private CSharpSymbolicExpressionTreeStringFormatter(CSharpSymbolicExpressionTreeStringFormatter original, Cloner cloner) : base(original, cloner) { }
+    public CSharpSymbolicExpressionTreeStringFormatter()
+      : base() {
+      Name = ItemName;
+      Description = ItemDescription;
+    }
+    public override IDeepCloneable Clone(Cloner cloner) {
+      return new CSharpSymbolicExpressionTreeStringFormatter(this, cloner);
+    }
+
+    public string Format(ISymbolicExpressionTree symbolicExpressionTree) {
+      // skip root and start symbols
+      StringBuilder strBuilder = new StringBuilder();
+      GenerateHeader(strBuilder, symbolicExpressionTree);
+      FormatRecursively(symbolicExpressionTree.Root.GetSubtree(0).GetSubtree(0), strBuilder);
+      GenerateFooter(strBuilder);
+      return strBuilder.ToString();
+    }
+
+    private void FormatRecursively(ISymbolicExpressionTreeNode node, StringBuilder strBuilder) {
+      if (node.Subtrees.Any()) {
+        if (node.Symbol is Addition) {
+          FormatOperator(node, "+", strBuilder);
+        } else if (node.Symbol is And) {
+          FormatOperator(node, "&&", strBuilder);
+        } else if (node.Symbol is Average) {
+          FormatFunction(node, "Average", strBuilder);
+        } else if (node.Symbol is Cosine) {
+          FormatFunction(node, "Math.Cos", strBuilder);
+        } else if (node.Symbol is Division) {
+          FormatDivision(node, strBuilder);
+        } else if (node.Symbol is Exponential) {
+          FormatFunction(node, "Math.Exp", strBuilder);
+        } else if (node.Symbol is GreaterThan) {
+          FormatOperator(node, ">", strBuilder);
+        } else if (node.Symbol is IfThenElse) {
+          FormatFunction(node, "EvaluateIf", strBuilder);
+        } else if (node.Symbol is LessThan) {
+          FormatOperator(node, "<", strBuilder);
+        } else if (node.Symbol is Logarithm) {
+          FormatFunction(node, "Math.Log", strBuilder);
+        } else if (node.Symbol is Multiplication) {
+          FormatOperator(node, "*", strBuilder);
+        } else if (node.Symbol is Not) {
+          FormatOperator(node, "!", strBuilder);
+        } else if (node.Symbol is Or) {
+          FormatOperator(node, "||", strBuilder);
+        } else if (node.Symbol is Sine) {
+          FormatFunction(node, "Math.Sin", strBuilder);
+        } else if (node.Symbol is Subtraction) {
+          FormatOperator(node, "-", strBuilder);
+        } else if (node.Symbol is Tangent) {
+          FormatFunction(node, "Math.Tan", strBuilder);
+        } else if (node.Symbol is Square) {
+          FormatSquare(node, strBuilder);
+        } else if (node.Symbol is SquareRoot) {
+          FormatFunction(node, "Math.Sqrt", strBuilder);
+        } else if (node.Symbol is Power) {
+          FormatFunction(node, "Math.Pow", strBuilder);
+        } else if (node.Symbol is Root) {
+          FormatRoot(node, strBuilder);
+        } else {
+          throw new NotSupportedException("Formatting of symbol: " + node.Symbol + " not supported for C# symbolic expression tree formatter.");
+        }
+      } else {
+        if (node is VariableTreeNode) {
+          var varNode = node as VariableTreeNode;
+          strBuilder.AppendFormat("{0} * {1}", varNode.VariableName, varNode.Weight.ToString("g17", CultureInfo.InvariantCulture));
+        } else if (node is ConstantTreeNode) {
+          var constNode = node as ConstantTreeNode;
+          strBuilder.Append(constNode.Value.ToString("g17", CultureInfo.InvariantCulture));
+        } else {
+          throw new NotSupportedException("Formatting of symbol: " + node.Symbol + " not supported for C# symbolic expression tree formatter.");
+        }
+      }
+    }
+
+    private void FormatSquare(ISymbolicExpressionTreeNode node, StringBuilder strBuilder) {
+      strBuilder.Append("Math.Pow(");
+      FormatRecursively(node.GetSubtree(0), strBuilder);
+      strBuilder.Append(", 2)");
+    }
+
+    private void FormatRoot(ISymbolicExpressionTreeNode node, StringBuilder strBuilder) {
+      strBuilder.Append("Math.Pow(");
+      FormatRecursively(node.GetSubtree(0), strBuilder);
+      strBuilder.Append(", 1.0 / (");
+      FormatRecursively(node.GetSubtree(1), strBuilder);
+      strBuilder.Append("))");
+    }
+
+    private void FormatDivision(ISymbolicExpressionTreeNode node, StringBuilder strBuilder) {
+      if (node.SubtreeCount == 1) {
+        strBuilder.Append("1.0 / ");
+        FormatRecursively(node.GetSubtree(0), strBuilder);
+      } else {
+        FormatRecursively(node.GetSubtree(0), strBuilder);
+        strBuilder.Append("/ (");
+        for (int i = 1; i < node.SubtreeCount; i++) {
+          if (i > 1) strBuilder.Append(" * ");
+          FormatRecursively(node.GetSubtree(i), strBuilder);
+        }
+        strBuilder.Append(")");
+      }
+    }
+
+    private void FormatOperator(ISymbolicExpressionTreeNode node, string symbol, StringBuilder strBuilder) {
+      strBuilder.Append("(");
+      foreach (var child in node.Subtrees) {
+        FormatRecursively(child, strBuilder);
+        if (child != node.Subtrees.Last())
+          strBuilder.Append(" " + symbol + " ");
+      }
+      strBuilder.Append(")");
+    }
+
+    private void FormatFunction(ISymbolicExpressionTreeNode node, string function, StringBuilder strBuilder) {
+      strBuilder.Append(function + "(");
+      foreach (var child in node.Subtrees) {
+        FormatRecursively(child, strBuilder);
+        if (child != node.Subtrees.Last())
+          strBuilder.Append(", ");
+      }
+      strBuilder.Append(")");
+    }
+
+    private void GenerateHeader(StringBuilder strBuilder, ISymbolicExpressionTree symbolicExpressionTree) {
+      strBuilder.AppendLine("using System;");
+      strBuilder.AppendLine("using System.Linq;" + Environment.NewLine);
+      strBuilder.AppendLine("namespace HeuristicLab.Models {");
+      strBuilder.AppendLine("public static class Model {");
+      GenerateAverageSource(strBuilder);
+      GenerateIfThenElseSource(strBuilder);
+      strBuilder.Append(Environment.NewLine + "public static double Evaluate (");
+
+      HashSet<string> varNames = new HashSet<string>();
+      foreach (var node in symbolicExpressionTree.IterateNodesPostfix().Where(x => x is VariableTreeNode)) {
+        varNames.Add(((VariableTreeNode)node).VariableName);
+      }
+
+      var orderedNames = varNames.OrderBy(n => n, new NaturalStringComparer()).Select(n=> "double " + n);
+      strBuilder.Append(string.Join(", ", orderedNames));
+
+      strBuilder.AppendLine(") {");
+      strBuilder.Append("double result = ");
+    }
+
+    private void GenerateFooter(StringBuilder strBuilder) {
+      strBuilder.AppendLine(";");
+      strBuilder.AppendLine("return result;");
+      strBuilder.AppendLine("}");
+      strBuilder.AppendLine("}");
+      strBuilder.AppendLine("}");
+    }
+
+    private void GenerateAverageSource(StringBuilder strBuilder) {
+      strBuilder.AppendLine("private static double Average(params double[] values) {");
+      strBuilder.AppendLine("  return values.Average();");
+      strBuilder.AppendLine("}");
+    }
+
+    private void GenerateIfThenElseSource(StringBuilder strBuilder) {
+      strBuilder.AppendLine("private static double EvaluateIf(bool condition, double then, double @else) {");
+      strBuilder.AppendLine("   return condition ? then : @else;");
+      strBuilder.AppendLine("}");
+    }
+  }
+}
Index: stable/HeuristicLab.Problems.DataAnalysis.Symbolic/3.4/HeuristicLab.Problems.DataAnalysis.Symbolic-3.4.csproj
===================================================================
--- stable/HeuristicLab.Problems.DataAnalysis.Symbolic/3.4/HeuristicLab.Problems.DataAnalysis.Symbolic-3.4.csproj	(revision 12639)
+++ stable/HeuristicLab.Problems.DataAnalysis.Symbolic/3.4/HeuristicLab.Problems.DataAnalysis.Symbolic-3.4.csproj	(revision 12652)
@@ -133,4 +133,5 @@
       <SubType>Code</SubType>
     </Compile>
+    <Compile Include="Formatters\SymbolicDataAnalysisExpressionCSharpFormatter.cs" />
     <Compile Include="Importer\SymbolicExpressionImporter.cs" />
     <Compile Include="Importer\Token.cs" />
