Index: branches/HivePerformance/sources/HeuristicLab.Problems.DataAnalysis.Symbolic/3.4/Formatters/SymbolicDataAnalysisExpressionExcelFormatter.cs
===================================================================
--- branches/HivePerformance/sources/HeuristicLab.Problems.DataAnalysis.Symbolic/3.4/Formatters/SymbolicDataAnalysisExpressionExcelFormatter.cs	(revision 9616)
+++ branches/HivePerformance/sources/HeuristicLab.Problems.DataAnalysis.Symbolic/3.4/Formatters/SymbolicDataAnalysisExpressionExcelFormatter.cs	(revision 9655)
@@ -23,4 +23,5 @@
 using System.Collections.Generic;
 using System.Globalization;
+using System.Linq;
 using System.Text;
 using HeuristicLab.Common;
@@ -66,9 +67,15 @@
       return string.Format("${0}1", variableNameMapping[variabelName]);
     }
-
     public string Format(ISymbolicExpressionTree symbolicExpressionTree) {
+      return Format(symbolicExpressionTree, null);
+    }
+
+    public string Format(ISymbolicExpressionTree symbolicExpressionTree, Dataset dataset) {
       var stringBuilder = new StringBuilder();
+      if (dataset != null) CalculateVariableMapping(symbolicExpressionTree, dataset);
+
       stringBuilder.Append("=");
       stringBuilder.Append(FormatRecursively(symbolicExpressionTree.Root));
+
       foreach (var variable in variableNameMapping) {
         stringBuilder.AppendLine();
@@ -76,4 +83,16 @@
       }
       return stringBuilder.ToString();
+    }
+
+    private void CalculateVariableMapping(ISymbolicExpressionTree tree, Dataset dataset) {
+      int columnIndex = 0;
+      int inputIndex = 0;
+      var usedVariables = tree.IterateNodesPrefix().OfType<VariableTreeNode>().Select(v => v.VariableName).Distinct();
+      foreach (var variable in dataset.VariableNames) {
+        columnIndex++;
+        if (!usedVariables.Contains(variable)) continue;
+        inputIndex++;
+        variableNameMapping[variable] = GetExcelColumnName(inputIndex);
+      }
     }
 
@@ -137,7 +156,7 @@
         stringBuilder.Append(")");
       } else if (symbol is Logarithm) {
-        stringBuilder.Append("LOG(");
-        stringBuilder.Append(FormatRecursively(node.GetSubtree(0)));
-        stringBuilder.Append(", EXP(1))"); // Excel does not use the natural logarithm, therefor the base has to be set
+        stringBuilder.Append("LN(");
+        stringBuilder.Append(FormatRecursively(node.GetSubtree(0)));
+        stringBuilder.Append(")");
       } else if (symbol is Multiplication) {
         for (int i = 0; i < node.SubtreeCount; i++) {
Index: branches/HivePerformance/sources/HeuristicLab.Problems.DataAnalysis.Symbolic/3.4/Formatters/SymbolicExpressionTreeSmalltalkStringFormatter.cs
===================================================================
--- branches/HivePerformance/sources/HeuristicLab.Problems.DataAnalysis.Symbolic/3.4/Formatters/SymbolicExpressionTreeSmalltalkStringFormatter.cs	(revision 9655)
+++ branches/HivePerformance/sources/HeuristicLab.Problems.DataAnalysis.Symbolic/3.4/Formatters/SymbolicExpressionTreeSmalltalkStringFormatter.cs	(revision 9655)
@@ -0,0 +1,178 @@
+﻿#region License Information
+/* HeuristicLab
+ * Copyright (C) 2002-2010 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.Text;
+using HeuristicLab.Core;
+using HeuristicLab.Common;
+using HeuristicLab.Problems.DataAnalysis.Symbolic;
+using Variable = HeuristicLab.Problems.DataAnalysis.Symbolic.Variable;
+
+namespace HeuristicLab.Encodings.SymbolicExpressionTreeEncoding.Formatters {
+
+  [Item("Smalltalk String Formatter", "String formatter for string representations of symbolic expression trees in Smalltalk syntax.")]
+  public class SymbolicExpressionTreeSmalltalkStringFormatter : NamedItem, ISymbolicExpressionTreeStringFormatter {
+
+    protected SymbolicExpressionTreeSmalltalkStringFormatter(SymbolicExpressionTreeSmalltalkStringFormatter original, Cloner cloner) : base(original, cloner) { }
+    public SymbolicExpressionTreeSmalltalkStringFormatter()
+      : base() {
+      Name = "Smalltalk String Formatter";
+    }
+
+    public string Format(ISymbolicExpressionTree symbolicExpressionTree) {
+      return FormatRecursively(symbolicExpressionTree.Root);
+    }
+
+    private string FormatRecursively(ISymbolicExpressionTreeNode node) {
+
+      ISymbol symbol = node.Symbol;
+
+      if (symbol is ProgramRootSymbol || symbol is StartSymbol)
+        return FormatRecursively(node.GetSubtree(0));
+
+      StringBuilder stringBuilder = new StringBuilder();
+
+      stringBuilder.Append("(");
+
+      if (symbol is Addition) {
+        for (int i = 0; i < node.SubtreeCount; i++) {
+          if (i > 0) stringBuilder.Append("+");
+          stringBuilder.Append(FormatRecursively(node.GetSubtree(i)));
+        }
+      } else if (symbol is And) {
+        stringBuilder.Append("(");
+        for (int i = 0; i < node.SubtreeCount; i++) {
+          if (i > 0) stringBuilder.Append("&");
+          stringBuilder.Append("((");
+          stringBuilder.Append(FormatRecursively(node.GetSubtree(i)));
+          stringBuilder.Append(")>=0)");
+        }
+        stringBuilder.Append(") ifTrue:[1] ifFalse:[-1]");
+      } else if (symbol is Average) {
+        stringBuilder.Append("(1/");
+        stringBuilder.Append(node.SubtreeCount);
+        stringBuilder.Append(")*(");
+        for (int i = 0; i < node.SubtreeCount; i++) {
+          if (i > 0) stringBuilder.Append("+");
+          stringBuilder.Append("(");
+          stringBuilder.Append(FormatRecursively(node.GetSubtree(i)));
+          stringBuilder.Append(")");
+        }
+        stringBuilder.Append(")");
+      } else if (symbol is Constant) {
+        ConstantTreeNode constantTreeNode = node as ConstantTreeNode;
+        stringBuilder.Append(constantTreeNode.Value.ToString().Replace(",", "."));
+      } else if (symbol is Cosine) {
+        stringBuilder.Append(FormatRecursively(node.GetSubtree(0)));
+        stringBuilder.Append(" cos");
+      } else if (symbol is Division) {
+        if (node.SubtreeCount == 1) {
+          stringBuilder.Append("1/");
+          stringBuilder.Append(FormatRecursively(node.GetSubtree(0)));
+        } else {
+          stringBuilder.Append(FormatRecursively(node.GetSubtree(0)));
+          stringBuilder.Append("/(");
+          for (int i = 1; i < node.SubtreeCount; i++) {
+            if (i > 1) stringBuilder.Append("*");
+            stringBuilder.Append(FormatRecursively(node.GetSubtree(i)));
+          }
+          stringBuilder.Append(")");
+        }
+      } else if (symbol is Exponential) {
+        stringBuilder.Append(FormatRecursively(node.GetSubtree(0)));
+        stringBuilder.Append(" exp");
+      } else if (symbol is GreaterThan) {
+        stringBuilder.Append("(");
+        stringBuilder.Append(FormatRecursively(node.GetSubtree(0)));
+        stringBuilder.Append(" > ");
+        stringBuilder.Append(FormatRecursively(node.GetSubtree(1)));
+        stringBuilder.Append(") ifTrue: [1] ifFalse: [-1]");
+      } else if (symbol is IfThenElse) {
+        stringBuilder.Append("(");
+        stringBuilder.Append(FormatRecursively(node.GetSubtree(0)));
+        stringBuilder.Append(" > 0) ifTrue: [");
+        stringBuilder.Append(FormatRecursively(node.GetSubtree(1)));
+        stringBuilder.Append("] ifFalse: [");
+        stringBuilder.Append(FormatRecursively(node.GetSubtree(2)));
+        stringBuilder.Append("]");
+      } else if (symbol is LaggedVariable) {
+        stringBuilder.Append("not implemented");
+      } else if (symbol is LessThan) {
+        stringBuilder.Append("(");
+        stringBuilder.Append(FormatRecursively(node.GetSubtree(0)));
+        stringBuilder.Append(" < ");
+        stringBuilder.Append(FormatRecursively(node.GetSubtree(1)));
+        stringBuilder.Append(") ifTrue: [1] ifFalse: [-1]");
+      } else if (symbol is Logarithm) {
+        stringBuilder.Append(FormatRecursively(node.GetSubtree(0)));
+        stringBuilder.Append("ln");
+      } else if (symbol is Multiplication) {
+        for (int i = 0; i < node.SubtreeCount; i++) {
+          if (i > 0) stringBuilder.Append("*");
+          stringBuilder.Append(FormatRecursively(node.GetSubtree(i)));
+        }
+      } else if (symbol is Not) {
+        stringBuilder.Append("-1*");
+        stringBuilder.Append(FormatRecursively(node.GetSubtree(0)));
+      } else if (symbol is Or) {
+        stringBuilder.Append("(");
+        for (int i = 0; i < node.SubtreeCount; i++) {
+          if (i > 0) stringBuilder.Append("|");
+          stringBuilder.Append("((");
+          stringBuilder.Append(FormatRecursively(node.GetSubtree(i)));
+          stringBuilder.Append(")>=0)");
+        }
+        stringBuilder.Append(") ifTrue:[1] ifFalse:[-1]");
+      } else if (symbol is Sine) {
+        stringBuilder.Append(FormatRecursively(node.GetSubtree(0)));
+        stringBuilder.Append(" sin");
+      } else if (symbol is Subtraction) {
+        if (node.SubtreeCount == 1) {
+          stringBuilder.Append("-1*");
+          stringBuilder.Append(FormatRecursively(node.GetSubtree(0)));
+        } else {
+          stringBuilder.Append(FormatRecursively(node.GetSubtree(0)));
+          for (int i = 1; i < node.SubtreeCount; i++) {
+            stringBuilder.Append("-");
+            stringBuilder.Append(FormatRecursively(node.GetSubtree(i)));
+          }
+        }
+      } else if (symbol is Tangent) {
+        stringBuilder.Append(FormatRecursively(node.GetSubtree(0)));
+        stringBuilder.Append("tan");
+      } else if (symbol is Variable) {
+        VariableTreeNode variableTreeNode = node as VariableTreeNode;
+        stringBuilder.Append(variableTreeNode.Weight.ToString().Replace(",", "."));
+        stringBuilder.Append("*");
+        stringBuilder.Append(variableTreeNode.VariableName);
+      } else {
+        stringBuilder.Append("ERROR");
+      }
+
+      stringBuilder.Append(")");
+
+      return stringBuilder.ToString();
+    }
+
+    public override IDeepCloneable Clone(Cloner cloner) {
+      return new SymbolicExpressionTreeSmalltalkStringFormatter(this, cloner);
+    }
+  }
+}
Index: branches/HivePerformance/sources/HeuristicLab.Problems.DataAnalysis.Symbolic/3.4/HeuristicLab.Problems.DataAnalysis.Symbolic-3.4.csproj
===================================================================
--- branches/HivePerformance/sources/HeuristicLab.Problems.DataAnalysis.Symbolic/3.4/HeuristicLab.Problems.DataAnalysis.Symbolic-3.4.csproj	(revision 9616)
+++ branches/HivePerformance/sources/HeuristicLab.Problems.DataAnalysis.Symbolic/3.4/HeuristicLab.Problems.DataAnalysis.Symbolic-3.4.csproj	(revision 9655)
@@ -140,4 +140,5 @@
     <Compile Include="Crossovers\SymbolicDataAnalysisExpressionSemanticSimilarityCrossover.cs" />
     <Compile Include="Formatters\SymbolicDataAnalysisExpressionExcelFormatter.cs" />
+    <Compile Include="Formatters\SymbolicExpressionTreeSmalltalkStringFormatter.cs" />
     <Compile Include="Interfaces\ISymbolicDataAnalysisExpressionCrossover.cs" />
     <Compile Include="Interfaces\ISymbolicDataAnalysisImpactValuesCalculator.cs" />
