Index: /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression-3.4.csproj
===================================================================
--- /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression-3.4.csproj	(revision 7748)
+++ /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression-3.4.csproj	(revision 7748)
@@ -0,0 +1,246 @@
+﻿<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="4.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <PropertyGroup>
+    <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
+    <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
+    <ProductVersion>9.0.30729</ProductVersion>
+    <SchemaVersion>2.0</SchemaVersion>
+    <ProjectGuid>{5AC82412-911B-4FA2-A013-EDC5E3F3FCC2}</ProjectGuid>
+    <OutputType>Library</OutputType>
+    <AppDesignerFolder>Properties</AppDesignerFolder>
+    <RootNamespace>HeuristicLab.Problems.DataAnalysis.Symbolic.Regression</RootNamespace>
+    <AssemblyName>HeuristicLab.Problems.DataAnalysis.Symbolic.Regression-3.4</AssemblyName>
+    <TargetFrameworkVersion>v4.0</TargetFrameworkVersion>
+    <TargetFrameworkProfile>
+    </TargetFrameworkProfile>
+    <FileAlignment>512</FileAlignment>
+    <SignAssembly>true</SignAssembly>
+    <AssemblyOriginatorKeyFile>HeuristicLab.snk</AssemblyOriginatorKeyFile>
+    <FileUpgradeFlags>
+    </FileUpgradeFlags>
+    <OldToolsVersion>3.5</OldToolsVersion>
+    <UpgradeBackupLocation />
+    <PublishUrl>publish\</PublishUrl>
+    <Install>true</Install>
+    <InstallFrom>Disk</InstallFrom>
+    <UpdateEnabled>false</UpdateEnabled>
+    <UpdateMode>Foreground</UpdateMode>
+    <UpdateInterval>7</UpdateInterval>
+    <UpdateIntervalUnits>Days</UpdateIntervalUnits>
+    <UpdatePeriodically>false</UpdatePeriodically>
+    <UpdateRequired>false</UpdateRequired>
+    <MapFileExtensions>true</MapFileExtensions>
+    <ApplicationRevision>0</ApplicationRevision>
+    <ApplicationVersion>1.0.0.%2a</ApplicationVersion>
+    <IsWebBootstrapper>false</IsWebBootstrapper>
+    <UseApplicationTrust>false</UseApplicationTrust>
+    <BootstrapperEnabled>true</BootstrapperEnabled>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
+    <DebugSymbols>true</DebugSymbols>
+    <DebugType>full</DebugType>
+    <Optimize>false</Optimize>
+    <OutputPath>$(SolutionDir)\bin\</OutputPath>
+    <DefineConstants>DEBUG;TRACE</DefineConstants>
+    <ErrorReport>prompt</ErrorReport>
+    <WarningLevel>4</WarningLevel>
+    <CodeAnalysisRuleSet>AllRules.ruleset</CodeAnalysisRuleSet>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
+    <DebugType>pdbonly</DebugType>
+    <Optimize>true</Optimize>
+    <OutputPath>$(SolutionDir)\bin\</OutputPath>
+    <DefineConstants>TRACE</DefineConstants>
+    <ErrorReport>prompt</ErrorReport>
+    <WarningLevel>4</WarningLevel>
+    <CodeAnalysisRuleSet>AllRules.ruleset</CodeAnalysisRuleSet>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|x64' ">
+    <DebugSymbols>true</DebugSymbols>
+    <OutputPath>$(SolutionDir)\bin\</OutputPath>
+    <DefineConstants>DEBUG;TRACE</DefineConstants>
+    <DebugType>full</DebugType>
+    <PlatformTarget>x64</PlatformTarget>
+    <ErrorReport>prompt</ErrorReport>
+    <CodeAnalysisRuleSet>AllRules.ruleset</CodeAnalysisRuleSet>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|x64' ">
+    <OutputPath>$(SolutionDir)\bin\</OutputPath>
+    <DefineConstants>TRACE</DefineConstants>
+    <Optimize>true</Optimize>
+    <DebugType>pdbonly</DebugType>
+    <PlatformTarget>x64</PlatformTarget>
+    <ErrorReport>prompt</ErrorReport>
+    <CodeAnalysisRuleSet>AllRules.ruleset</CodeAnalysisRuleSet>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|x86' ">
+    <DebugSymbols>true</DebugSymbols>
+    <OutputPath>$(SolutionDir)\bin\</OutputPath>
+    <DefineConstants>DEBUG;TRACE</DefineConstants>
+    <DebugType>full</DebugType>
+    <PlatformTarget>x86</PlatformTarget>
+    <ErrorReport>prompt</ErrorReport>
+    <CodeAnalysisRuleSet>AllRules.ruleset</CodeAnalysisRuleSet>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|x86' ">
+    <OutputPath>$(SolutionDir)\bin\</OutputPath>
+    <DefineConstants>TRACE</DefineConstants>
+    <Optimize>true</Optimize>
+    <DebugType>pdbonly</DebugType>
+    <PlatformTarget>x86</PlatformTarget>
+    <ErrorReport>prompt</ErrorReport>
+    <CodeAnalysisRuleSet>AllRules.ruleset</CodeAnalysisRuleSet>
+  </PropertyGroup>
+  <ItemGroup>
+    <Reference Include="ALGLIB-3.5.0, Version=3.5.0.0, Culture=neutral, PublicKeyToken=ba48961d6f65dcec, processorArchitecture=MSIL">
+      <HintPath>..\..\bin\ALGLIB-3.5.0.dll</HintPath>
+      <Private>False</Private>
+    </Reference>
+    <Reference Include="System" />
+    <Reference Include="System.Core">
+      <RequiredTargetFramework>3.5</RequiredTargetFramework>
+    </Reference>
+    <Reference Include="System.Drawing" />
+    <Reference Include="System.Xml.Linq">
+      <RequiredTargetFramework>3.5</RequiredTargetFramework>
+    </Reference>
+    <Reference Include="System.Data.DataSetExtensions">
+      <RequiredTargetFramework>3.5</RequiredTargetFramework>
+    </Reference>
+    <Reference Include="System.Data" />
+    <Reference Include="System.Xml" />
+  </ItemGroup>
+  <ItemGroup>
+    <Compile Include="MultiObjective\SymbolicRegressionMultiObjectiveValidationBestSolutionAnalyzer.cs" />
+    <Compile Include="Plugin.cs" />
+    <Compile Include="SingleObjective\SymbolicRegressionSingleObjectiveValidationParetoBestSolutionAnalyzer.cs" />
+    <Compile Include="SingleObjective\SymbolicRegressionSingleObjectiveTrainingParetoBestSolutionAnalyzer.cs" />
+    <Compile Include="SingleObjective\Evaluators\SymbolicRegressionSingleObjectiveMaxAbsoluteErrorEvaluator.cs" />
+    <Compile Include="SingleObjective\Evaluators\SymbolicRegressionSingleObjectiveMeanAbsoluteErrorEvaluator.cs" />
+    <Compile Include="SingleObjective\Evaluators\SymbolicRegressionConstantOptimizationEvaluator.cs" />
+    <Compile Include="SingleObjective\SymbolicRegressionSingleObjectiveOverfittingAnalyzer.cs" />
+    <Compile Include="SymbolicRegressionModel.cs" />
+    <Compile Include="Interfaces\ISymbolicRegressionModel.cs" />
+    <Compile Include="Interfaces\ISymbolicRegressionSolution.cs" />
+    <Compile Include="Interfaces\ISymbolicRegressionEvaluator.cs" />
+    <Compile Include="Interfaces\ISymbolicRegressionMultiObjectiveEvaluator.cs" />
+    <Compile Include="Interfaces\ISymbolicRegressionSingleObjectiveEvaluator.cs" />
+    <Compile Include="MultiObjective\SymbolicRegressionMultiObjectiveProblem.cs" />
+    <Compile Include="MultiObjective\SymbolicRegressionMultiObjectiveTrainingBestSolutionAnalyzer.cs" />
+    <Compile Include="SingleObjective\SymbolicRegressionSingleObjectiveProblem.cs" />
+    <Compile Include="SingleObjective\SymbolicRegressionSingleObjectiveValidationBestSolutionAnalyzer.cs" />
+    <Compile Include="SingleObjective\SymbolicRegressionSingleObjectiveTrainingBestSolutionAnalyzer.cs" />
+    <Compile Include="MultiObjective\SymbolicRegressionMultiObjectiveEvaluator.cs" />
+    <Compile Include="MultiObjective\SymbolicRegressionMultiObjectiveMeanSquaredErrorTreeSizeEvaluator.cs" />
+    <Compile Include="MultiObjective\SymbolicRegressionMultiObjectivePearsonRSquaredTreeSizeEvaluator.cs" />
+    <Compile Include="SingleObjective\Evaluators\SymbolicRegressionSingleObjectiveEvaluator.cs" />
+    <Compile Include="SingleObjective\Evaluators\SymbolicRegressionSingleObjectiveMeanSquaredErrorEvaluator.cs" />
+    <Compile Include="SingleObjective\Evaluators\SymbolicRegressionSingleObjectivePearsonRSquaredEvaluator.cs" />
+    <Compile Include="SymbolicRegressionSolution.cs" />
+    <None Include="HeuristicLab.snk" />
+    <None Include="Plugin.cs.frame" />
+    <None Include="Properties\AssemblyInfo.cs.frame" />
+    <Compile Include="Properties\AssemblyInfo.cs" />
+  </ItemGroup>
+  <ItemGroup>
+    <ProjectReference Include="..\..\HeuristicLab.Analysis\3.3\HeuristicLab.Analysis-3.3.csproj">
+      <Project>{887425B4-4348-49ED-A457-B7D2C26DDBF9}</Project>
+      <Name>HeuristicLab.Analysis-3.3</Name>
+      <Private>False</Private>
+    </ProjectReference>
+    <ProjectReference Include="..\..\HeuristicLab.Collections\3.3\HeuristicLab.Collections-3.3.csproj">
+      <Project>{958B43BC-CC5C-4FA2-8628-2B3B01D890B6}</Project>
+      <Name>HeuristicLab.Collections-3.3</Name>
+      <Private>False</Private>
+    </ProjectReference>
+    <ProjectReference Include="..\..\HeuristicLab.Common\3.3\HeuristicLab.Common-3.3.csproj">
+      <Project>{A9AD58B9-3EF9-4CC1-97E5-8D909039FF5C}</Project>
+      <Name>HeuristicLab.Common-3.3</Name>
+      <Private>False</Private>
+    </ProjectReference>
+    <ProjectReference Include="..\..\HeuristicLab.Core\3.3\HeuristicLab.Core-3.3.csproj">
+      <Project>{C36BD924-A541-4A00-AFA8-41701378DDC5}</Project>
+      <Name>HeuristicLab.Core-3.3</Name>
+      <Private>False</Private>
+    </ProjectReference>
+    <ProjectReference Include="..\..\HeuristicLab.Data\3.3\HeuristicLab.Data-3.3.csproj">
+      <Project>{BBAB9DF5-5EF3-4BA8-ADE9-B36E82114937}</Project>
+      <Name>HeuristicLab.Data-3.3</Name>
+      <Private>False</Private>
+    </ProjectReference>
+    <ProjectReference Include="..\..\HeuristicLab.Encodings.SymbolicExpressionTreeEncoding\3.4\HeuristicLab.Encodings.SymbolicExpressionTreeEncoding-3.4.csproj">
+      <Project>{06D4A186-9319-48A0-BADE-A2058D462EEA}</Project>
+      <Name>HeuristicLab.Encodings.SymbolicExpressionTreeEncoding-3.4</Name>
+      <Private>False</Private>
+    </ProjectReference>
+    <ProjectReference Include="..\..\HeuristicLab.Operators\3.3\HeuristicLab.Operators-3.3.csproj">
+      <Project>{23DA7FF4-D5B8-41B6-AA96-F0561D24F3EE}</Project>
+      <Name>HeuristicLab.Operators-3.3</Name>
+      <Private>False</Private>
+    </ProjectReference>
+    <ProjectReference Include="..\..\HeuristicLab.Optimization\3.3\HeuristicLab.Optimization-3.3.csproj">
+      <Project>{14AB8D24-25BC-400C-A846-4627AA945192}</Project>
+      <Name>HeuristicLab.Optimization-3.3</Name>
+      <Private>False</Private>
+    </ProjectReference>
+    <ProjectReference Include="..\..\HeuristicLab.Parameters\3.3\HeuristicLab.Parameters-3.3.csproj">
+      <Project>{56F9106A-079F-4C61-92F6-86A84C2D84B7}</Project>
+      <Name>HeuristicLab.Parameters-3.3</Name>
+      <Private>False</Private>
+    </ProjectReference>
+    <ProjectReference Include="..\..\HeuristicLab.Persistence\3.3\HeuristicLab.Persistence-3.3.csproj">
+      <Project>{102BC7D3-0EF9-439C-8F6D-96FF0FDB8E1B}</Project>
+      <Name>HeuristicLab.Persistence-3.3</Name>
+      <Private>False</Private>
+    </ProjectReference>
+    <ProjectReference Include="..\..\HeuristicLab.PluginInfrastructure\3.3\HeuristicLab.PluginInfrastructure-3.3.csproj">
+      <Project>{94186A6A-5176-4402-AE83-886557B53CCA}</Project>
+      <Name>HeuristicLab.PluginInfrastructure-3.3</Name>
+      <Private>False</Private>
+    </ProjectReference>
+    <ProjectReference Include="..\..\HeuristicLab.Problems.DataAnalysis.Symbolic\3.4\HeuristicLab.Problems.DataAnalysis.Symbolic-3.4.csproj">
+      <Project>{3D28463F-EC96-4D82-AFEE-38BE91A0CA00}</Project>
+      <Name>HeuristicLab.Problems.DataAnalysis.Symbolic-3.4</Name>
+      <Private>False</Private>
+    </ProjectReference>
+    <ProjectReference Include="..\..\HeuristicLab.Problems.DataAnalysis\3.4\HeuristicLab.Problems.DataAnalysis-3.4.csproj">
+      <Project>{DF87C13E-A889-46FF-8153-66DCAA8C5674}</Project>
+      <Name>HeuristicLab.Problems.DataAnalysis-3.4</Name>
+      <Private>False</Private>
+    </ProjectReference>
+  </ItemGroup>
+  <ItemGroup>
+    <BootstrapperPackage Include="Microsoft.Net.Client.3.5">
+      <Visible>False</Visible>
+      <ProductName>.NET Framework 3.5 SP1 Client Profile</ProductName>
+      <Install>false</Install>
+    </BootstrapperPackage>
+    <BootstrapperPackage Include="Microsoft.Net.Framework.3.5.SP1">
+      <Visible>False</Visible>
+      <ProductName>.NET Framework 3.5 SP1</ProductName>
+      <Install>true</Install>
+    </BootstrapperPackage>
+    <BootstrapperPackage Include="Microsoft.Windows.Installer.3.1">
+      <Visible>False</Visible>
+      <ProductName>Windows Installer 3.1</ProductName>
+      <Install>true</Install>
+    </BootstrapperPackage>
+  </ItemGroup>
+  <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
+  <!-- To modify your build process, add your task inside one of the targets below and uncomment it. 
+       Other similar extension points exist, see Microsoft.Common.targets.
+  <Target Name="BeforeBuild">
+  </Target>
+  <Target Name="AfterBuild">
+  </Target>
+  -->
+  <PropertyGroup>
+    <PreBuildEvent>set Path=%25Path%25;$(ProjectDir);$(SolutionDir)
+set ProjectDir=$(ProjectDir)
+set SolutionDir=$(SolutionDir)
+set Outdir=$(Outdir)
+
+call PreBuildEvent.cmd
+</PreBuildEvent>
+  </PropertyGroup>
+</Project>
Index: /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/Interfaces/ISymbolicRegressionEvaluator.cs
===================================================================
--- /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/Interfaces/ISymbolicRegressionEvaluator.cs	(revision 7748)
+++ /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/Interfaces/ISymbolicRegressionEvaluator.cs	(revision 7748)
@@ -0,0 +1,26 @@
+﻿#region License Information
+/* HeuristicLab
+ * Copyright (C) 2002-2012 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
+
+
+namespace HeuristicLab.Problems.DataAnalysis.Symbolic.Regression {
+  public interface ISymbolicRegressionEvaluator : ISymbolicDataAnalysisEvaluator<IRegressionProblemData> {
+  }
+}
Index: /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/Interfaces/ISymbolicRegressionModel.cs
===================================================================
--- /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/Interfaces/ISymbolicRegressionModel.cs	(revision 7748)
+++ /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/Interfaces/ISymbolicRegressionModel.cs	(revision 7748)
@@ -0,0 +1,26 @@
+﻿#region License Information
+/* HeuristicLab
+ * Copyright (C) 2002-2012 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 HeuristicLab.Encodings.SymbolicExpressionTreeEncoding;
+namespace HeuristicLab.Problems.DataAnalysis.Symbolic.Regression {
+  public interface ISymbolicRegressionModel : IRegressionModel, ISymbolicDataAnalysisModel {
+  }
+}
Index: /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/Interfaces/ISymbolicRegressionMultiObjectiveEvaluator.cs
===================================================================
--- /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/Interfaces/ISymbolicRegressionMultiObjectiveEvaluator.cs	(revision 7748)
+++ /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/Interfaces/ISymbolicRegressionMultiObjectiveEvaluator.cs	(revision 7748)
@@ -0,0 +1,25 @@
+﻿#region License Information
+/* HeuristicLab
+ * Copyright (C) 2002-2012 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
+
+namespace HeuristicLab.Problems.DataAnalysis.Symbolic.Regression {
+  public interface ISymbolicRegressionMultiObjectiveEvaluator : ISymbolicRegressionEvaluator, ISymbolicDataAnalysisMultiObjectiveEvaluator<IRegressionProblemData> {
+  }
+}
Index: /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/Interfaces/ISymbolicRegressionSingleObjectiveEvaluator.cs
===================================================================
--- /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/Interfaces/ISymbolicRegressionSingleObjectiveEvaluator.cs	(revision 7748)
+++ /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/Interfaces/ISymbolicRegressionSingleObjectiveEvaluator.cs	(revision 7748)
@@ -0,0 +1,25 @@
+﻿#region License Information
+/* HeuristicLab
+ * Copyright (C) 2002-2012 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
+
+namespace HeuristicLab.Problems.DataAnalysis.Symbolic.Regression {
+  public interface ISymbolicRegressionSingleObjectiveEvaluator : ISymbolicRegressionEvaluator, ISymbolicDataAnalysisSingleObjectiveEvaluator<IRegressionProblemData> {
+  }
+}
Index: /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/Interfaces/ISymbolicRegressionSolution.cs
===================================================================
--- /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/Interfaces/ISymbolicRegressionSolution.cs	(revision 7748)
+++ /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/Interfaces/ISymbolicRegressionSolution.cs	(revision 7748)
@@ -0,0 +1,28 @@
+﻿#region License Information
+/* HeuristicLab
+ * Copyright (C) 2002-2012 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 HeuristicLab.Problems.DataAnalysis.Symbolic;
+namespace HeuristicLab.Problems.DataAnalysis.Symbolic.Regression {
+  public interface ISymbolicRegressionSolution : IRegressionSolution, ISymbolicDataAnalysisSolution {
+    new ISymbolicRegressionModel Model { get; }
+  }
+}
Index: /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/MultiObjective/SymbolicRegressionMultiObjectiveEvaluator.cs
===================================================================
--- /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/MultiObjective/SymbolicRegressionMultiObjectiveEvaluator.cs	(revision 7748)
+++ /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/MultiObjective/SymbolicRegressionMultiObjectiveEvaluator.cs	(revision 7748)
@@ -0,0 +1,35 @@
+﻿#region License Information
+/* HeuristicLab
+ * Copyright (C) 2002-2012 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 HeuristicLab.Common;
+using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
+namespace HeuristicLab.Problems.DataAnalysis.Symbolic.Regression {
+  public abstract class SymbolicRegressionMultiObjectiveEvaluator : SymbolicDataAnalysisMultiObjectiveEvaluator<IRegressionProblemData>, ISymbolicRegressionMultiObjectiveEvaluator {
+    [StorableConstructor]
+    protected SymbolicRegressionMultiObjectiveEvaluator(bool deserializing) : base(deserializing) { }
+    protected SymbolicRegressionMultiObjectiveEvaluator(SymbolicRegressionMultiObjectiveEvaluator original, Cloner cloner)
+      : base(original, cloner) {
+    }
+
+    protected SymbolicRegressionMultiObjectiveEvaluator() : base() { }
+  }
+}
Index: /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/MultiObjective/SymbolicRegressionMultiObjectiveMeanSquaredErrorTreeSizeEvaluator.cs
===================================================================
--- /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/MultiObjective/SymbolicRegressionMultiObjectiveMeanSquaredErrorTreeSizeEvaluator.cs	(revision 7748)
+++ /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/MultiObjective/SymbolicRegressionMultiObjectiveMeanSquaredErrorTreeSizeEvaluator.cs	(revision 7748)
@@ -0,0 +1,76 @@
+﻿#region License Information
+/* HeuristicLab
+ * Copyright (C) 2002-2012 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.Collections.Generic;
+using HeuristicLab.Common;
+using HeuristicLab.Core;
+using HeuristicLab.Data;
+using HeuristicLab.Encodings.SymbolicExpressionTreeEncoding;
+using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
+
+namespace HeuristicLab.Problems.DataAnalysis.Symbolic.Regression {
+  [Item("Mean squared error & Tree size Evaluator", "Calculates the mean squared error and the tree size of a symbolic regression solution.")]
+  [StorableClass]
+  public class SymbolicRegressionMultiObjectiveMeanSquaredErrorSolutionSizeEvaluator : SymbolicRegressionMultiObjectiveEvaluator {
+    [StorableConstructor]
+    protected SymbolicRegressionMultiObjectiveMeanSquaredErrorSolutionSizeEvaluator(bool deserializing) : base(deserializing) { }
+    protected SymbolicRegressionMultiObjectiveMeanSquaredErrorSolutionSizeEvaluator(SymbolicRegressionMultiObjectiveMeanSquaredErrorSolutionSizeEvaluator original, Cloner cloner)
+      : base(original, cloner) {
+    }
+    public override IDeepCloneable Clone(Cloner cloner) {
+      return new SymbolicRegressionMultiObjectiveMeanSquaredErrorSolutionSizeEvaluator(this, cloner);
+    }
+
+    public SymbolicRegressionMultiObjectiveMeanSquaredErrorSolutionSizeEvaluator() : base() { }
+
+    public override IEnumerable<bool> Maximization { get { return new bool[2] { false, false }; } }
+
+    public override Core.IOperation Apply() {
+      IEnumerable<int> rows = GenerateRowsToEvaluate();
+      var solution = SymbolicExpressionTreeParameter.ActualValue;
+      double[] qualities = Calculate(SymbolicDataAnalysisTreeInterpreterParameter.ActualValue, solution, EstimationLimitsParameter.ActualValue.Lower, EstimationLimitsParameter.ActualValue.Upper, ProblemDataParameter.ActualValue, rows);
+      QualitiesParameter.ActualValue = new DoubleArray(qualities);
+      return base.Apply();
+    }
+
+    public static double[] Calculate(ISymbolicDataAnalysisExpressionTreeInterpreter interpreter, ISymbolicExpressionTree solution, double lowerEstimationLimit, double upperEstimationLimit, IRegressionProblemData problemData, IEnumerable<int> rows) {
+      IEnumerable<double> estimatedValues = interpreter.GetSymbolicExpressionTreeValues(solution, problemData.Dataset, rows);
+      IEnumerable<double> originalValues = problemData.Dataset.GetDoubleValues(problemData.TargetVariable, rows);
+      IEnumerable<double> boundedEstimationValues = estimatedValues.LimitToRange(lowerEstimationLimit, upperEstimationLimit);
+      OnlineCalculatorError errorState;
+      double mse = OnlineMeanSquaredErrorCalculator.Calculate(originalValues, boundedEstimationValues, out errorState);
+      if (errorState != OnlineCalculatorError.None) mse = double.NaN;
+      return new double[2] { mse, solution.Length };
+    }
+
+    public override double[] Evaluate(IExecutionContext context, ISymbolicExpressionTree tree, IRegressionProblemData problemData, IEnumerable<int> rows) {
+      SymbolicDataAnalysisTreeInterpreterParameter.ExecutionContext = context;
+      EstimationLimitsParameter.ExecutionContext = context;
+
+      double[] quality = Calculate(SymbolicDataAnalysisTreeInterpreterParameter.ActualValue, tree, EstimationLimitsParameter.ActualValue.Lower, EstimationLimitsParameter.ActualValue.Upper, problemData, rows);
+
+      SymbolicDataAnalysisTreeInterpreterParameter.ExecutionContext = null;
+      EstimationLimitsParameter.ExecutionContext = null;
+
+      return quality;
+    }
+  }
+}
Index: /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/MultiObjective/SymbolicRegressionMultiObjectivePearsonRSquaredTreeSizeEvaluator.cs
===================================================================
--- /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/MultiObjective/SymbolicRegressionMultiObjectivePearsonRSquaredTreeSizeEvaluator.cs	(revision 7748)
+++ /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/MultiObjective/SymbolicRegressionMultiObjectivePearsonRSquaredTreeSizeEvaluator.cs	(revision 7748)
@@ -0,0 +1,75 @@
+﻿#region License Information
+/* HeuristicLab
+ * Copyright (C) 2002-2012 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.Collections.Generic;
+using HeuristicLab.Common;
+using HeuristicLab.Core;
+using HeuristicLab.Data;
+using HeuristicLab.Encodings.SymbolicExpressionTreeEncoding;
+using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
+
+namespace HeuristicLab.Problems.DataAnalysis.Symbolic.Regression {
+  [Item("Pearson R² & Tree size Evaluator", "Calculates the Pearson R² and the tree size of a symbolic regression solution.")]
+  [StorableClass]
+  public class SymbolicRegressionMultiObjectivePearsonRSquaredTreeSizeEvaluator : SymbolicRegressionMultiObjectiveEvaluator {
+    [StorableConstructor]
+    protected SymbolicRegressionMultiObjectivePearsonRSquaredTreeSizeEvaluator(bool deserializing) : base(deserializing) { }
+    protected SymbolicRegressionMultiObjectivePearsonRSquaredTreeSizeEvaluator(SymbolicRegressionMultiObjectivePearsonRSquaredTreeSizeEvaluator original, Cloner cloner)
+      : base(original, cloner) {
+    }
+    public override IDeepCloneable Clone(Cloner cloner) {
+      return new SymbolicRegressionMultiObjectivePearsonRSquaredTreeSizeEvaluator(this, cloner);
+    }
+
+    public SymbolicRegressionMultiObjectivePearsonRSquaredTreeSizeEvaluator() : base() { }
+
+    public override IEnumerable<bool> Maximization { get { return new bool[2] { true, false }; } }
+
+    public override IOperation Apply() {
+      IEnumerable<int> rows = GenerateRowsToEvaluate();
+      var solution = SymbolicExpressionTreeParameter.ActualValue;
+      double[] qualities = Calculate(SymbolicDataAnalysisTreeInterpreterParameter.ActualValue, solution, EstimationLimitsParameter.ActualValue.Lower, EstimationLimitsParameter.ActualValue.Upper, ProblemDataParameter.ActualValue, rows);
+      QualitiesParameter.ActualValue = new DoubleArray(qualities);
+      return base.Apply();
+    }
+
+    public static double[] Calculate(ISymbolicDataAnalysisExpressionTreeInterpreter interpreter, ISymbolicExpressionTree solution, double lowerEstimationLimit, double upperEstimationLimit, IRegressionProblemData problemData, IEnumerable<int> rows) {
+      IEnumerable<double> estimatedValues = interpreter.GetSymbolicExpressionTreeValues(solution, problemData.Dataset, rows);
+      IEnumerable<double> originalValues = problemData.Dataset.GetDoubleValues(problemData.TargetVariable, rows);
+      OnlineCalculatorError errorState;
+      double r2 = OnlinePearsonsRSquaredCalculator.Calculate(estimatedValues, originalValues, out errorState);
+      if (errorState != OnlineCalculatorError.None) r2 = 0.0;
+      return new double[] { r2, solution.Length };
+    }
+
+    public override double[] Evaluate(IExecutionContext context, ISymbolicExpressionTree tree, IRegressionProblemData problemData, IEnumerable<int> rows) {
+      SymbolicDataAnalysisTreeInterpreterParameter.ExecutionContext = context;
+      EstimationLimitsParameter.ExecutionContext = context;
+
+      double[] quality = Calculate(SymbolicDataAnalysisTreeInterpreterParameter.ActualValue, tree, EstimationLimitsParameter.ActualValue.Lower, EstimationLimitsParameter.ActualValue.Upper, problemData, rows);
+
+      SymbolicDataAnalysisTreeInterpreterParameter.ExecutionContext = null;
+      EstimationLimitsParameter.ExecutionContext = null;
+
+      return quality;
+    }
+  }
+}
Index: /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/MultiObjective/SymbolicRegressionMultiObjectiveProblem.cs
===================================================================
--- /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/MultiObjective/SymbolicRegressionMultiObjectiveProblem.cs	(revision 7748)
+++ /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/MultiObjective/SymbolicRegressionMultiObjectiveProblem.cs	(revision 7748)
@@ -0,0 +1,119 @@
+﻿#region License Information
+/* HeuristicLab
+ * Copyright (C) 2002-2012 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.Linq;
+using HeuristicLab.Common;
+using HeuristicLab.Core;
+using HeuristicLab.Data;
+using HeuristicLab.Parameters;
+using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
+
+namespace HeuristicLab.Problems.DataAnalysis.Symbolic.Regression {
+  [Item("Symbolic Regression Problem (multi objective)", "Represents a multi objective symbolic regression problem.")]
+  [StorableClass]
+  [Creatable("Problems")]
+  public class SymbolicRegressionMultiObjectiveProblem : SymbolicDataAnalysisMultiObjectiveProblem<IRegressionProblemData, ISymbolicRegressionMultiObjectiveEvaluator, ISymbolicDataAnalysisSolutionCreator>, IRegressionProblem {
+    private const double PunishmentFactor = 10;
+    private const int InitialMaximumTreeDepth = 8;
+    private const int InitialMaximumTreeLength = 25;
+    private const string EstimationLimitsParameterName = "EstimationLimits";
+    private const string EstimationLimitsParameterDescription = "The lower and upper limit for the estimated value that can be returned by the symbolic regression model.";
+
+    #region parameter properties
+    public IFixedValueParameter<DoubleLimit> EstimationLimitsParameter {
+      get { return (IFixedValueParameter<DoubleLimit>)Parameters[EstimationLimitsParameterName]; }
+    }
+    #endregion
+
+    #region properties
+    public DoubleLimit EstimationLimits {
+      get { return EstimationLimitsParameter.Value; }
+    }
+
+    #endregion
+
+    [StorableConstructor]
+    protected SymbolicRegressionMultiObjectiveProblem(bool deserializing) : base(deserializing) { }
+    protected SymbolicRegressionMultiObjectiveProblem(SymbolicRegressionMultiObjectiveProblem original, Cloner cloner) : base(original, cloner) { }
+    public override IDeepCloneable Clone(Cloner cloner) { return new SymbolicRegressionMultiObjectiveProblem(this, cloner); }
+
+    public SymbolicRegressionMultiObjectiveProblem()
+      : base(new RegressionProblemData(), new SymbolicRegressionMultiObjectivePearsonRSquaredTreeSizeEvaluator(), new SymbolicDataAnalysisExpressionTreeCreator()) {
+      Parameters.Add(new FixedValueParameter<DoubleLimit>(EstimationLimitsParameterName, EstimationLimitsParameterDescription));
+
+      EstimationLimitsParameter.Hidden = true;
+
+      Maximization = new BoolArray(new bool[] { true, false });
+      MaximumSymbolicExpressionTreeDepth.Value = InitialMaximumTreeDepth;
+      MaximumSymbolicExpressionTreeLength.Value = InitialMaximumTreeLength;
+
+      SymbolicExpressionTreeGrammarParameter.ValueChanged += (o, e) => ConfigureGrammarSymbols();
+
+      ConfigureGrammarSymbols();
+      InitializeOperators();
+      UpdateEstimationLimits();
+    }
+
+    private void ConfigureGrammarSymbols() {
+      var grammar = SymbolicExpressionTreeGrammar as TypeCoherentExpressionGrammar;
+      if (grammar != null) grammar.ConfigureAsDefaultRegressionGrammar();
+    }
+
+    private void InitializeOperators() {
+      Operators.Add(new SymbolicRegressionMultiObjectiveTrainingBestSolutionAnalyzer());
+      Operators.Add(new SymbolicRegressionMultiObjectiveValidationBestSolutionAnalyzer());
+      ParameterizeOperators();
+    }
+
+    private void UpdateEstimationLimits() {
+      if (ProblemData.TrainingIndizes.Any()) {
+        var targetValues = ProblemData.Dataset.GetDoubleValues(ProblemData.TargetVariable, ProblemData.TrainingIndizes).ToList();
+        var mean = targetValues.Average();
+        var range = targetValues.Max() - targetValues.Min();
+        EstimationLimits.Upper = mean + PunishmentFactor * range;
+        EstimationLimits.Lower = mean - PunishmentFactor * range;
+      } else {
+        EstimationLimits.Upper = double.MaxValue;
+        EstimationLimits.Lower = double.MinValue;
+      }
+    }
+
+    protected override void OnProblemDataChanged() {
+      base.OnProblemDataChanged();
+      UpdateEstimationLimits();
+    }
+
+    protected override void ParameterizeOperators() {
+      base.ParameterizeOperators();
+      if (Parameters.ContainsKey(EstimationLimitsParameterName)) {
+        var operators = Parameters.OfType<IValueParameter>().Select(p => p.Value).OfType<IOperator>().Union(Operators);
+        foreach (var op in operators.OfType<ISymbolicDataAnalysisBoundedOperator>()) {
+          op.EstimationLimitsParameter.ActualName = EstimationLimitsParameter.Name;
+        }
+      }
+    }
+
+    public override void ImportProblemDataFromFile(string fileName) {
+      RegressionProblemData problemData = RegressionProblemData.ImportFromFile(fileName);
+      ProblemData = problemData;
+    }
+  }
+}
Index: /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/MultiObjective/SymbolicRegressionMultiObjectiveTrainingBestSolutionAnalyzer.cs
===================================================================
--- /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/MultiObjective/SymbolicRegressionMultiObjectiveTrainingBestSolutionAnalyzer.cs	(revision 7748)
+++ /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/MultiObjective/SymbolicRegressionMultiObjectiveTrainingBestSolutionAnalyzer.cs	(revision 7748)
@@ -0,0 +1,84 @@
+#region License Information
+/* HeuristicLab
+ * Copyright (C) 2002-2012 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 HeuristicLab.Common;
+using HeuristicLab.Core;
+using HeuristicLab.Data;
+using HeuristicLab.Encodings.SymbolicExpressionTreeEncoding;
+using HeuristicLab.Parameters;
+using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
+
+namespace HeuristicLab.Problems.DataAnalysis.Symbolic.Regression {
+  /// <summary>
+  /// An operator that analyzes the training best symbolic regression solution for multi objective symbolic regression problems.
+  /// </summary>
+  [Item("SymbolicRegressionMultiObjectiveTrainingBestSolutionAnalyzer", "An operator that analyzes the training best symbolic regression solution for multi objective symbolic regression problems.")]
+  [StorableClass]
+  public sealed class SymbolicRegressionMultiObjectiveTrainingBestSolutionAnalyzer : SymbolicDataAnalysisMultiObjectiveTrainingBestSolutionAnalyzer<ISymbolicRegressionSolution>,
+    ISymbolicDataAnalysisInterpreterOperator, ISymbolicDataAnalysisBoundedOperator {
+    private const string ProblemDataParameterName = "ProblemData";
+    private const string SymbolicDataAnalysisTreeInterpreterParameterName = "SymbolicDataAnalysisTreeInterpreter";
+    private const string EstimationLimitsParameterName = "EstimationLimits";
+    private const string ApplyLinearScalingParameterName = "ApplyLinearScaling";
+    #region parameter properties
+    public ILookupParameter<IRegressionProblemData> ProblemDataParameter {
+      get { return (ILookupParameter<IRegressionProblemData>)Parameters[ProblemDataParameterName]; }
+    }
+    public ILookupParameter<ISymbolicDataAnalysisExpressionTreeInterpreter> SymbolicDataAnalysisTreeInterpreterParameter {
+      get { return (ILookupParameter<ISymbolicDataAnalysisExpressionTreeInterpreter>)Parameters[SymbolicDataAnalysisTreeInterpreterParameterName]; }
+    }
+    public IValueLookupParameter<DoubleLimit> EstimationLimitsParameter {
+      get { return (IValueLookupParameter<DoubleLimit>)Parameters[EstimationLimitsParameterName]; }
+    }
+    public IValueParameter<BoolValue> ApplyLinearScalingParameter {
+      get { return (IValueParameter<BoolValue>)Parameters[ApplyLinearScalingParameterName]; }
+    }
+    #endregion
+
+    #region properties
+    public BoolValue ApplyLinearScaling {
+      get { return ApplyLinearScalingParameter.Value; }
+    }
+    #endregion
+
+    [StorableConstructor]
+    private SymbolicRegressionMultiObjectiveTrainingBestSolutionAnalyzer(bool deserializing) : base(deserializing) { }
+    private SymbolicRegressionMultiObjectiveTrainingBestSolutionAnalyzer(SymbolicRegressionMultiObjectiveTrainingBestSolutionAnalyzer original, Cloner cloner) : base(original, cloner) { }
+    public SymbolicRegressionMultiObjectiveTrainingBestSolutionAnalyzer()
+      : base() {
+      Parameters.Add(new LookupParameter<IRegressionProblemData>(ProblemDataParameterName, "The problem data for the symbolic regression solution."));
+      Parameters.Add(new LookupParameter<ISymbolicDataAnalysisExpressionTreeInterpreter>(SymbolicDataAnalysisTreeInterpreterParameterName, "The symbolic data analysis tree interpreter for the symbolic expression tree."));
+      Parameters.Add(new ValueLookupParameter<DoubleLimit>(EstimationLimitsParameterName, "The lower and upper limit for the estimated values produced by the symbolic regression model."));
+      Parameters.Add(new ValueParameter<BoolValue>(ApplyLinearScalingParameterName, "Flag that indicates if the produced symbolic regression solution should be linearly scaled.", new BoolValue(true)));
+    }
+
+    public override IDeepCloneable Clone(Cloner cloner) {
+      return new SymbolicRegressionMultiObjectiveTrainingBestSolutionAnalyzer(this, cloner);
+    }
+
+    protected override ISymbolicRegressionSolution CreateSolution(ISymbolicExpressionTree bestTree, double[] bestQuality) {
+      var model = new SymbolicRegressionModel((ISymbolicExpressionTree)bestTree.Clone(), SymbolicDataAnalysisTreeInterpreterParameter.ActualValue, EstimationLimitsParameter.ActualValue.Lower, EstimationLimitsParameter.ActualValue.Upper);
+      if (ApplyLinearScaling.Value)
+        SymbolicRegressionModel.Scale(model, ProblemDataParameter.ActualValue);
+      return new SymbolicRegressionSolution(model, (IRegressionProblemData)ProblemDataParameter.ActualValue.Clone());
+    }
+  }
+}
Index: /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/MultiObjective/SymbolicRegressionMultiObjectiveValidationBestSolutionAnalyzer.cs
===================================================================
--- /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/MultiObjective/SymbolicRegressionMultiObjectiveValidationBestSolutionAnalyzer.cs	(revision 7748)
+++ /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/MultiObjective/SymbolicRegressionMultiObjectiveValidationBestSolutionAnalyzer.cs	(revision 7748)
@@ -0,0 +1,73 @@
+#region License Information
+/* HeuristicLab
+ * Copyright (C) 2002-2012 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 HeuristicLab.Common;
+using HeuristicLab.Core;
+using HeuristicLab.Data;
+using HeuristicLab.Encodings.SymbolicExpressionTreeEncoding;
+using HeuristicLab.Parameters;
+using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
+
+namespace HeuristicLab.Problems.DataAnalysis.Symbolic.Regression {
+  /// <summary>
+  /// An operator that analyzes the validation best symbolic regression solution for multi objective symbolic regression problems.
+  /// </summary>
+  [Item("SymbolicRegressionMultiObjectiveValidationBestSolutionAnalyzer", "An operator that analyzes the validation best symbolic regression solution for multi objective symbolic regression problems.")]
+  [StorableClass]
+  public sealed class SymbolicRegressionMultiObjectiveValidationBestSolutionAnalyzer : SymbolicDataAnalysisMultiObjectiveValidationBestSolutionAnalyzer<ISymbolicRegressionSolution, ISymbolicRegressionMultiObjectiveEvaluator, IRegressionProblemData>,
+    ISymbolicDataAnalysisBoundedOperator {
+    private const string EstimationLimitsParameterName = "EstimationLimits";
+    private const string ApplyLinearScalingParameterName = "ApplyLinearScaling";
+
+    #region parameter properties
+    public IValueLookupParameter<DoubleLimit> EstimationLimitsParameter {
+      get { return (IValueLookupParameter<DoubleLimit>)Parameters[EstimationLimitsParameterName]; }
+    }
+    public IValueParameter<BoolValue> ApplyLinearScalingParameter {
+      get { return (IValueParameter<BoolValue>)Parameters[ApplyLinearScalingParameterName]; }
+    }
+    #endregion
+
+    #region properties
+    public BoolValue ApplyLinearScaling {
+      get { return ApplyLinearScalingParameter.Value; }
+    }
+    #endregion
+    [StorableConstructor]
+    private SymbolicRegressionMultiObjectiveValidationBestSolutionAnalyzer(bool deserializing) : base(deserializing) { }
+    private SymbolicRegressionMultiObjectiveValidationBestSolutionAnalyzer(SymbolicRegressionMultiObjectiveValidationBestSolutionAnalyzer original, Cloner cloner) : base(original, cloner) { }
+    public SymbolicRegressionMultiObjectiveValidationBestSolutionAnalyzer()
+      : base() {
+      Parameters.Add(new ValueLookupParameter<DoubleLimit>(EstimationLimitsParameterName, "The lower and upper limit for the estimated values produced by the symbolic regression model."));
+      Parameters.Add(new ValueParameter<BoolValue>(ApplyLinearScalingParameterName, "Flag that indicates if the produced symbolic regression solution should be linearly scaled.", new BoolValue(true)));
+    }
+    public override IDeepCloneable Clone(Cloner cloner) {
+      return new SymbolicRegressionMultiObjectiveValidationBestSolutionAnalyzer(this, cloner);
+    }
+
+    protected override ISymbolicRegressionSolution CreateSolution(ISymbolicExpressionTree bestTree, double[] bestQuality) {
+      var model = new SymbolicRegressionModel((ISymbolicExpressionTree)bestTree.Clone(), SymbolicDataAnalysisTreeInterpreterParameter.ActualValue, EstimationLimitsParameter.ActualValue.Lower, EstimationLimitsParameter.ActualValue.Upper);
+      if (ApplyLinearScaling.Value)
+        SymbolicRegressionModel.Scale(model, ProblemDataParameter.ActualValue);
+      return new SymbolicRegressionSolution(model, (IRegressionProblemData)ProblemDataParameter.ActualValue.Clone());
+    }
+  }
+}
Index: /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/Plugin.cs.frame
===================================================================
--- /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/Plugin.cs.frame	(revision 7748)
+++ /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/Plugin.cs.frame	(revision 7748)
@@ -0,0 +1,45 @@
+#region License Information
+/* HeuristicLab
+ * Copyright (C) 2002-2012 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.Text;
+using HeuristicLab.PluginInfrastructure;
+
+namespace HeuristicLab.Problems.DataAnalysis.Symbolic.Regression {
+  [Plugin("HeuristicLab.Problems.DataAnalysis.Symbolic.Regression","Provides classes to perform symbolic regression (single- or multiobjective).", "3.4.2.$WCREV$")]
+  [PluginFile("HeuristicLab.Problems.DataAnalysis.Symbolic.Regression-3.4.dll", PluginFileType.Assembly)]
+  [PluginDependency("HeuristicLab.ALGLIB", "3.5")]
+  [PluginDependency("HeuristicLab.Analysis", "3.3")]
+  [PluginDependency("HeuristicLab.Common", "3.3")]
+  [PluginDependency("HeuristicLab.Collections", "3.3")]
+  [PluginDependency("HeuristicLab.Core", "3.3")]
+  [PluginDependency("HeuristicLab.Data", "3.3")]
+  [PluginDependency("HeuristicLab.Encodings.SymbolicExpressionTreeEncoding", "3.4")]
+  [PluginDependency("HeuristicLab.Operators", "3.3")]
+  [PluginDependency("HeuristicLab.Optimization", "3.3")]
+  [PluginDependency("HeuristicLab.Parameters", "3.3")]
+  [PluginDependency("HeuristicLab.Persistence", "3.3")]
+  [PluginDependency("HeuristicLab.Problems.DataAnalysis", "3.4")]
+  [PluginDependency("HeuristicLab.Problems.DataAnalysis.Symbolic", "3.4")]
+  public class HeuristicLabProblemsDataAnalysisSymbolicRegressionPlugin : PluginBase {
+  }
+}
Index: /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/Properties/AssemblyInfo.cs.frame
===================================================================
--- /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/Properties/AssemblyInfo.cs.frame	(revision 7748)
+++ /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/Properties/AssemblyInfo.cs.frame	(revision 7748)
@@ -0,0 +1,55 @@
+#region License Information
+/* HeuristicLab
+ * Copyright (C) 2002-2012 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.Reflection;
+using System.Runtime.InteropServices;
+
+// General Information about an assembly is controlled through the following 
+// set of attributes. Change these attribute values to modify the information
+// associated with an assembly.
+[assembly: AssemblyTitle("HeuristicLab.Problems.DataAnalysis.Symbolic.Regression")]
+[assembly: AssemblyDescription("Provides classes to perform symbolic regression (single- or multiobjective).")]
+[assembly: AssemblyConfiguration("")]
+[assembly: AssemblyCompany("")]
+[assembly: AssemblyProduct("HeuristicLab")]
+[assembly: AssemblyCopyright("(c) 2002-2012 HEAL")]
+[assembly: AssemblyTrademark("")]
+[assembly: AssemblyCulture("")]
+
+// Setting ComVisible to false makes the types in this assembly not visible 
+// to COM components.  If you need to access a type in this assembly from 
+// COM, set the ComVisible attribute to true on that type.
+[assembly: ComVisible(false)]
+
+// The following GUID is for the ID of the typelib if this project is exposed to COM
+[assembly: Guid("08D73741-0242-4F40-BD0A-0E5506576893")]
+
+// Version information for an assembly consists of the following four values:
+//
+//      Major Version
+//      Minor Version 
+//      Build Number
+//      Revision
+//
+// You can specify all the values or you can default the Revision and Build Numbers 
+// by using the '*' as shown below:
+[assembly: AssemblyVersion("3.4.0.0")]
+[assembly: AssemblyFileVersion("3.4.2.$WCREV$")]
Index: /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/SingleObjective/Evaluators/SymbolicRegressionConstantOptimizationEvaluator.cs
===================================================================
--- /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/SingleObjective/Evaluators/SymbolicRegressionConstantOptimizationEvaluator.cs	(revision 7748)
+++ /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/SingleObjective/Evaluators/SymbolicRegressionConstantOptimizationEvaluator.cs	(revision 7748)
@@ -0,0 +1,214 @@
+#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.Collections.Generic;
+using System.Linq;
+using HeuristicLab.Common;
+using HeuristicLab.Core;
+using HeuristicLab.Data;
+using HeuristicLab.Encodings.SymbolicExpressionTreeEncoding;
+using HeuristicLab.Parameters;
+using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
+
+namespace HeuristicLab.Problems.DataAnalysis.Symbolic.Regression {
+  [Item("Constant Optimization Evaluator", "Calculates Pearson R² of a symbolic regression solution and optimizes the constant used.")]
+  [StorableClass]
+  public class SymbolicRegressionConstantOptimizationEvaluator : SymbolicRegressionSingleObjectiveEvaluator {
+    private const string ConstantOptimizationIterationsParameterName = "ConstantOptimizationIterations";
+    private const string ConstantOptimizationImprovementParameterName = "ConstantOptimizationImprovement";
+    private const string ConstantOptimizationProbabilityParameterName = "ConstantOptimizationProbability";
+    private const string ConstantOptimizationRowsPercentageParameterName = "ConstantOptimizationRowsPercentage";
+
+    private const string EvaluatedTreesResultName = "EvaluatedTrees";
+    private const string EvaluatedTreeNodesResultName = "EvaluatedTreeNodes";
+
+    public ILookupParameter<IntValue> EvaluatedTreesParameter {
+      get { return (ILookupParameter<IntValue>)Parameters[EvaluatedTreesResultName]; }
+    }
+    public ILookupParameter<IntValue> EvaluatedTreeNodesParameter {
+      get { return (ILookupParameter<IntValue>)Parameters[EvaluatedTreeNodesResultName]; }
+    }
+
+    public IFixedValueParameter<IntValue> ConstantOptimizationIterationsParameter {
+      get { return (IFixedValueParameter<IntValue>)Parameters[ConstantOptimizationIterationsParameterName]; }
+    }
+    public IFixedValueParameter<DoubleValue> ConstantOptimizationImprovementParameter {
+      get { return (IFixedValueParameter<DoubleValue>)Parameters[ConstantOptimizationImprovementParameterName]; }
+    }
+    public IFixedValueParameter<PercentValue> ConstantOptimizationProbabilityParameter {
+      get { return (IFixedValueParameter<PercentValue>)Parameters[ConstantOptimizationProbabilityParameterName]; }
+    }
+    public IFixedValueParameter<PercentValue> ConstantOptimizationRowsPercentageParameter {
+      get { return (IFixedValueParameter<PercentValue>)Parameters[ConstantOptimizationRowsPercentageParameterName]; }
+    }
+
+    public IntValue ConstantOptimizationIterations {
+      get { return ConstantOptimizationIterationsParameter.Value; }
+    }
+    public DoubleValue ConstantOptimizationImprovement {
+      get { return ConstantOptimizationImprovementParameter.Value; }
+    }
+    public PercentValue ConstantOptimizationProbability {
+      get { return ConstantOptimizationProbabilityParameter.Value; }
+    }
+    public PercentValue ConstantOptimizationRowsPercentage {
+      get { return ConstantOptimizationRowsPercentageParameter.Value; }
+    }
+
+    public override bool Maximization {
+      get { return true; }
+    }
+
+    [StorableConstructor]
+    protected SymbolicRegressionConstantOptimizationEvaluator(bool deserializing) : base(deserializing) { }
+    protected SymbolicRegressionConstantOptimizationEvaluator(SymbolicRegressionConstantOptimizationEvaluator original, Cloner cloner)
+      : base(original, cloner) {
+    }
+    public SymbolicRegressionConstantOptimizationEvaluator()
+      : base() {
+      Parameters.Add(new FixedValueParameter<IntValue>(ConstantOptimizationIterationsParameterName, "Determines how many iterations should be calculated while optimizing the constant of a symbolic expression tree (0 indicates other or default stopping criterion).", new IntValue(3), true));
+      Parameters.Add(new FixedValueParameter<DoubleValue>(ConstantOptimizationImprovementParameterName, "Determines the relative improvement which must be achieved in the constant optimization to continue with it (0 indicates other or default stopping criterion).", new DoubleValue(0), true));
+      Parameters.Add(new FixedValueParameter<PercentValue>(ConstantOptimizationProbabilityParameterName, "Determines the probability that the constants are optimized", new PercentValue(1), true));
+      Parameters.Add(new FixedValueParameter<PercentValue>(ConstantOptimizationRowsPercentageParameterName, "Determines the percentage of the rows which should be used for constant optimization", new PercentValue(1), true));
+
+      Parameters.Add(new LookupParameter<IntValue>(EvaluatedTreesResultName));
+      Parameters.Add(new LookupParameter<IntValue>(EvaluatedTreeNodesResultName));
+    }
+
+    public override IDeepCloneable Clone(Cloner cloner) {
+      return new SymbolicRegressionConstantOptimizationEvaluator(this, cloner);
+    }
+
+    public override IOperation Apply() {
+      AddResults();
+      int seed = RandomParameter.ActualValue.Next();
+      var solution = SymbolicExpressionTreeParameter.ActualValue;
+      double quality;
+      if (RandomParameter.ActualValue.NextDouble() < ConstantOptimizationProbability.Value) {
+        IEnumerable<int> constantOptimizationRows = GenerateRowsToEvaluate(ConstantOptimizationRowsPercentage.Value);
+        quality = OptimizeConstants(SymbolicDataAnalysisTreeInterpreterParameter.ActualValue, solution, ProblemDataParameter.ActualValue,
+           constantOptimizationRows, ConstantOptimizationImprovement.Value, ConstantOptimizationIterations.Value, 0.001,
+           EstimationLimitsParameter.ActualValue.Upper, EstimationLimitsParameter.ActualValue.Lower,
+          EvaluatedTreesParameter.ActualValue, EvaluatedTreeNodesParameter.ActualValue);
+        if (ConstantOptimizationRowsPercentage.Value != RelativeNumberOfEvaluatedSamplesParameter.ActualValue.Value) {
+          var evaluationRows = GenerateRowsToEvaluate();
+          quality = SymbolicRegressionSingleObjectivePearsonRSquaredEvaluator.Calculate(SymbolicDataAnalysisTreeInterpreterParameter.ActualValue, solution, EstimationLimitsParameter.ActualValue.Lower, EstimationLimitsParameter.ActualValue.Upper, ProblemDataParameter.ActualValue, evaluationRows);
+        }
+      } else {
+        var evaluationRows = GenerateRowsToEvaluate();
+        quality = SymbolicRegressionSingleObjectivePearsonRSquaredEvaluator.Calculate(SymbolicDataAnalysisTreeInterpreterParameter.ActualValue, solution, EstimationLimitsParameter.ActualValue.Lower, EstimationLimitsParameter.ActualValue.Upper, ProblemDataParameter.ActualValue, evaluationRows);
+      }
+      QualityParameter.ActualValue = new DoubleValue(quality);
+      EvaluatedTreesParameter.ActualValue.Value += 1;
+      EvaluatedTreeNodesParameter.ActualValue.Value += solution.Length;
+
+      if (Successor != null)
+        return ExecutionContext.CreateOperation(Successor);
+      else
+        return null;
+    }
+
+    private void AddResults() {
+      if (EvaluatedTreesParameter.ActualValue == null) {
+        var scope = ExecutionContext.Scope;
+        while (scope.Parent != null)
+          scope = scope.Parent;
+        scope.Variables.Add(new Core.Variable(EvaluatedTreesResultName, new IntValue()));
+      }
+      if (EvaluatedTreeNodesParameter.ActualValue == null) {
+        var scope = ExecutionContext.Scope;
+        while (scope.Parent != null)
+          scope = scope.Parent;
+        scope.Variables.Add(new Core.Variable(EvaluatedTreeNodesResultName, new IntValue()));
+      }
+    }
+
+    public override double Evaluate(IExecutionContext context, ISymbolicExpressionTree tree, IRegressionProblemData problemData, IEnumerable<int> rows) {
+      SymbolicDataAnalysisTreeInterpreterParameter.ExecutionContext = context;
+      EstimationLimitsParameter.ExecutionContext = context;
+
+      double r2 = SymbolicRegressionSingleObjectivePearsonRSquaredEvaluator.Calculate(SymbolicDataAnalysisTreeInterpreterParameter.ActualValue, tree, EstimationLimitsParameter.ActualValue.Lower, EstimationLimitsParameter.ActualValue.Upper, problemData, rows);
+
+      SymbolicDataAnalysisTreeInterpreterParameter.ExecutionContext = null;
+      EstimationLimitsParameter.ExecutionContext = null;
+
+      return r2;
+    }
+
+    public static double OptimizeConstants(ISymbolicDataAnalysisExpressionTreeInterpreter interpreter, ISymbolicExpressionTree tree, IRegressionProblemData problemData,
+      IEnumerable<int> rows, double improvement, int iterations, double differentialStep, double upperEstimationLimit = double.MaxValue, double lowerEstimationLimit = double.MinValue, IntValue evaluatedTrees = null, IntValue evaluatedTreeNodes = null) {
+      List<SymbolicExpressionTreeTerminalNode> terminalNodes = tree.Root.IterateNodesPrefix().OfType<SymbolicExpressionTreeTerminalNode>().ToList();
+      double[] c = new double[terminalNodes.Count];
+      int treeLength = tree.Length;
+
+      //extract inital constants
+      for (int i = 0; i < terminalNodes.Count; i++) {
+        ConstantTreeNode constantTreeNode = terminalNodes[i] as ConstantTreeNode;
+        if (constantTreeNode != null) c[i] = constantTreeNode.Value;
+        VariableTreeNode variableTreeNode = terminalNodes[i] as VariableTreeNode;
+        if (variableTreeNode != null) c[i] = variableTreeNode.Weight;
+      }
+
+      double epsg = 0;
+      double epsf = improvement;
+      double epsx = 0;
+      int maxits = iterations;
+      double diffstep = differentialStep;
+
+      alglib.minlmstate state;
+      alglib.minlmreport report;
+
+      alglib.minlmcreatev(1, c, diffstep, out state);
+      alglib.minlmsetcond(state, epsg, epsf, epsx, maxits);
+      alglib.minlmoptimize(state, CreateCallBack(interpreter, tree, problemData, rows, upperEstimationLimit, lowerEstimationLimit, treeLength, evaluatedTrees, evaluatedTreeNodes), null, terminalNodes);
+      alglib.minlmresults(state, out c, out report);
+
+      for (int i = 0; i < c.Length; i++) {
+        ConstantTreeNode constantTreeNode = terminalNodes[i] as ConstantTreeNode;
+        if (constantTreeNode != null) constantTreeNode.Value = c[i];
+        VariableTreeNode variableTreeNode = terminalNodes[i] as VariableTreeNode;
+        if (variableTreeNode != null) variableTreeNode.Weight = c[i];
+      }
+
+      return (state.fi[0] - 1) * -1;
+    }
+
+    private static alglib.ndimensional_fvec CreateCallBack(ISymbolicDataAnalysisExpressionTreeInterpreter interpreter, ISymbolicExpressionTree tree, IRegressionProblemData problemData, IEnumerable<int> rows, double upperEstimationLimit, double lowerEstimationLimit, int treeLength, IntValue evaluatedTrees = null, IntValue evaluatedTreeNodes = null) {
+      return (double[] arg, double[] fi, object obj) => {
+        // update constants of tree
+        List<SymbolicExpressionTreeTerminalNode> terminalNodes = (List<SymbolicExpressionTreeTerminalNode>)obj;
+        for (int i = 0; i < terminalNodes.Count; i++) {
+          ConstantTreeNode constantTreeNode = terminalNodes[i] as ConstantTreeNode;
+          if (constantTreeNode != null) constantTreeNode.Value = arg[i];
+          VariableTreeNode variableTreeNode = terminalNodes[i] as VariableTreeNode;
+          if (variableTreeNode != null) variableTreeNode.Weight = arg[i];
+        }
+
+        double quality = SymbolicRegressionSingleObjectivePearsonRSquaredEvaluator.Calculate(interpreter, tree, lowerEstimationLimit, upperEstimationLimit, problemData, rows);
+
+        fi[0] = 1 - quality;
+        if (evaluatedTrees != null) evaluatedTrees.Value++;
+        if (evaluatedTreeNodes != null) evaluatedTreeNodes.Value += treeLength;
+      };
+    }
+
+  }
+}
Index: /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/SingleObjective/Evaluators/SymbolicRegressionSingleObjectiveEvaluator.cs
===================================================================
--- /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/SingleObjective/Evaluators/SymbolicRegressionSingleObjectiveEvaluator.cs	(revision 7748)
+++ /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/SingleObjective/Evaluators/SymbolicRegressionSingleObjectiveEvaluator.cs	(revision 7748)
@@ -0,0 +1,94 @@
+﻿#region License Information
+/* HeuristicLab
+ * Copyright (C) 2002-2012 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 HeuristicLab.Common;
+using HeuristicLab.Core;
+using HeuristicLab.Data;
+using HeuristicLab.Parameters;
+using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
+namespace HeuristicLab.Problems.DataAnalysis.Symbolic.Regression {
+  [StorableClass]
+  public abstract class SymbolicRegressionSingleObjectiveEvaluator : SymbolicDataAnalysisSingleObjectiveEvaluator<IRegressionProblemData>, ISymbolicRegressionSingleObjectiveEvaluator {
+    private const string ApplyLinearScalingParameterName = "ApplyLinearScaling";
+    public IFixedValueParameter<BoolValue> ApplyLinearScalingParameter {
+      get { return (IFixedValueParameter<BoolValue>)Parameters[ApplyLinearScalingParameterName]; }
+    }
+    public bool ApplyLinearScaling {
+      get { return ApplyLinearScalingParameter.Value.Value; }
+      set { ApplyLinearScalingParameter.Value.Value = value; }
+    }
+
+    [StorableConstructor]
+    protected SymbolicRegressionSingleObjectiveEvaluator(bool deserializing) : base(deserializing) { }
+    protected SymbolicRegressionSingleObjectiveEvaluator(SymbolicRegressionSingleObjectiveEvaluator original, Cloner cloner) : base(original, cloner) { }
+    protected SymbolicRegressionSingleObjectiveEvaluator()
+      : base() {
+      Parameters.Add(new FixedValueParameter<BoolValue>(ApplyLinearScalingParameterName, "Flag that indicates if the individual should be linearly scaled before evaluating.", new BoolValue(true)));
+      ApplyLinearScalingParameter.Hidden = true;
+    }
+
+    [StorableHook(HookType.AfterDeserialization)]
+    private void AfterDeserialization() {
+      if (!Parameters.ContainsKey(ApplyLinearScalingParameterName)) {
+        Parameters.Add(new FixedValueParameter<BoolValue>(ApplyLinearScalingParameterName, "Flag that indicates if the individual should be linearly scaled before evaluating.", new BoolValue(false)));
+        ApplyLinearScalingParameter.Hidden = true;
+      }
+    }
+
+    [ThreadStatic]
+    private static double[] cache;
+
+    protected static void CalculateWithScaling(IEnumerable<double> targetValues, IEnumerable<double> estimatedValues, IOnlineCalculator calculator, int maxRows) {
+      if (cache == null || cache.GetLength(0) < maxRows) {
+        cache = new double[maxRows];
+      }
+
+      //calculate linear scaling
+      //the static methods of the calculator could not be used as it performs a check if the enumerators have an equal amount of elements
+      //this is not true if the cache is used
+      int i = 0;
+      var linearScalingCalculator = new OnlineLinearScalingParameterCalculator();
+      var targetValuesEnumerator = targetValues.GetEnumerator();
+      var estimatedValuesEnumerator = estimatedValues.GetEnumerator();
+      while (targetValuesEnumerator.MoveNext() && estimatedValuesEnumerator.MoveNext()) {
+        double target = targetValuesEnumerator.Current;
+        double estimated = estimatedValuesEnumerator.Current;
+        cache[i] = estimated;
+        linearScalingCalculator.Add(estimated, target);
+        i++;
+      }
+      double alpha = linearScalingCalculator.Alpha;
+      double beta = linearScalingCalculator.Beta;
+
+      //calculate the quality by using the passed online calculator
+      targetValuesEnumerator = targetValues.GetEnumerator();
+      i = 0;
+      while (targetValuesEnumerator.MoveNext()) {
+        double target = targetValuesEnumerator.Current;
+        double estimated = cache[i] * beta + alpha;
+        calculator.Add(target, estimated);
+        i++;
+      }
+    }
+  }
+}
Index: /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/SingleObjective/Evaluators/SymbolicRegressionSingleObjectiveMaxAbsoluteErrorEvaluator.cs
===================================================================
--- /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/SingleObjective/Evaluators/SymbolicRegressionSingleObjectiveMaxAbsoluteErrorEvaluator.cs	(revision 7748)
+++ /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/SingleObjective/Evaluators/SymbolicRegressionSingleObjectiveMaxAbsoluteErrorEvaluator.cs	(revision 7748)
@@ -0,0 +1,86 @@
+﻿#region License Information
+/* HeuristicLab
+ * Copyright (C) 2002-2012 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 HeuristicLab.Common;
+using HeuristicLab.Core;
+using HeuristicLab.Data;
+using HeuristicLab.Encodings.SymbolicExpressionTreeEncoding;
+using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
+
+namespace HeuristicLab.Problems.DataAnalysis.Symbolic.Regression {
+  [Item("Maximum absolute error Evaluator", "Calculates the maximum squared error of a symbolic regression solution.")]
+  [StorableClass]
+  public class SymbolicRegressionSingleObjectiveMaxAbsoluteErrorEvaluator : SymbolicRegressionSingleObjectiveEvaluator {
+    public override bool Maximization { get { return false; } }
+    [StorableConstructor]
+    protected SymbolicRegressionSingleObjectiveMaxAbsoluteErrorEvaluator(bool deserializing) : base(deserializing) { }
+    protected SymbolicRegressionSingleObjectiveMaxAbsoluteErrorEvaluator(SymbolicRegressionSingleObjectiveMaxAbsoluteErrorEvaluator original, Cloner cloner)
+      : base(original, cloner) {
+    }
+    public override IDeepCloneable Clone(Cloner cloner) {
+      return new SymbolicRegressionSingleObjectiveMaxAbsoluteErrorEvaluator(this, cloner);
+    }
+    public SymbolicRegressionSingleObjectiveMaxAbsoluteErrorEvaluator() : base() { }
+
+    public override IOperation Apply() {
+      var solution = SymbolicExpressionTreeParameter.ActualValue;
+      IEnumerable<int> rows = GenerateRowsToEvaluate();
+
+      double quality = Calculate(SymbolicDataAnalysisTreeInterpreterParameter.ActualValue, solution, EstimationLimitsParameter.ActualValue.Lower, EstimationLimitsParameter.ActualValue.Upper, ProblemDataParameter.ActualValue, rows, ApplyLinearScaling);
+      QualityParameter.ActualValue = new DoubleValue(quality);
+
+      return base.Apply();
+    }
+
+    public static double Calculate(ISymbolicDataAnalysisExpressionTreeInterpreter interpreter, ISymbolicExpressionTree solution, double lowerEstimationLimit, double upperEstimationLimit, IRegressionProblemData problemData, IEnumerable<int> rows, bool applyLinearScaling) {
+      IEnumerable<double> estimatedValues = interpreter.GetSymbolicExpressionTreeValues(solution, problemData.Dataset, rows);
+      IEnumerable<double> targetValues = problemData.Dataset.GetDoubleValues(problemData.TargetVariable, rows);
+      IEnumerable<double> boundedEstimatedValues = estimatedValues.LimitToRange(lowerEstimationLimit, upperEstimationLimit);
+      OnlineCalculatorError errorState;
+
+      double mse;
+      if (applyLinearScaling) {
+        var maeCalculator = new OnlineMaxAbsoluteErrorCalculator();
+        CalculateWithScaling(targetValues, boundedEstimatedValues, maeCalculator, problemData.Dataset.Rows);
+        errorState = maeCalculator.ErrorState;
+        mse = maeCalculator.MaxAbsoluteError;
+      } else
+        mse = OnlineMaxAbsoluteErrorCalculator.Calculate(targetValues, boundedEstimatedValues, out errorState);
+
+      if (errorState != OnlineCalculatorError.None) return Double.NaN;
+      else return mse;
+    }
+
+    public override double Evaluate(IExecutionContext context, ISymbolicExpressionTree tree, IRegressionProblemData problemData, IEnumerable<int> rows) {
+      SymbolicDataAnalysisTreeInterpreterParameter.ExecutionContext = context;
+      EstimationLimitsParameter.ExecutionContext = context;
+
+      double mse = Calculate(SymbolicDataAnalysisTreeInterpreterParameter.ActualValue, tree, EstimationLimitsParameter.ActualValue.Lower, EstimationLimitsParameter.ActualValue.Upper, problemData, rows, ApplyLinearScaling);
+
+      SymbolicDataAnalysisTreeInterpreterParameter.ExecutionContext = null;
+      EstimationLimitsParameter.ExecutionContext = null;
+
+      return mse;
+    }
+  }
+}
Index: /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/SingleObjective/Evaluators/SymbolicRegressionSingleObjectiveMeanAbsoluteErrorEvaluator.cs
===================================================================
--- /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/SingleObjective/Evaluators/SymbolicRegressionSingleObjectiveMeanAbsoluteErrorEvaluator.cs	(revision 7748)
+++ /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/SingleObjective/Evaluators/SymbolicRegressionSingleObjectiveMeanAbsoluteErrorEvaluator.cs	(revision 7748)
@@ -0,0 +1,86 @@
+﻿#region License Information
+/* HeuristicLab
+ * Copyright (C) 2002-2012 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 HeuristicLab.Common;
+using HeuristicLab.Core;
+using HeuristicLab.Data;
+using HeuristicLab.Encodings.SymbolicExpressionTreeEncoding;
+using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
+
+namespace HeuristicLab.Problems.DataAnalysis.Symbolic.Regression {
+  [Item("Mean absolute error Evaluator", "Calculates the mean absolute error of a symbolic regression solution.")]
+  [StorableClass]
+  public class SymbolicRegressionSingleObjectiveMeanAbsoluteErrorEvaluator : SymbolicRegressionSingleObjectiveEvaluator {
+    public override bool Maximization { get { return false; } }
+    [StorableConstructor]
+    protected SymbolicRegressionSingleObjectiveMeanAbsoluteErrorEvaluator(bool deserializing) : base(deserializing) { }
+    protected SymbolicRegressionSingleObjectiveMeanAbsoluteErrorEvaluator(SymbolicRegressionSingleObjectiveMeanAbsoluteErrorEvaluator original, Cloner cloner)
+      : base(original, cloner) {
+    }
+    public override IDeepCloneable Clone(Cloner cloner) {
+      return new SymbolicRegressionSingleObjectiveMeanAbsoluteErrorEvaluator(this, cloner);
+    }
+    public SymbolicRegressionSingleObjectiveMeanAbsoluteErrorEvaluator() : base() { }
+
+    public override IOperation Apply() {
+      var solution = SymbolicExpressionTreeParameter.ActualValue;
+      IEnumerable<int> rows = GenerateRowsToEvaluate();
+
+      double quality = Calculate(SymbolicDataAnalysisTreeInterpreterParameter.ActualValue, solution, EstimationLimitsParameter.ActualValue.Lower, EstimationLimitsParameter.ActualValue.Upper, ProblemDataParameter.ActualValue, rows, ApplyLinearScaling);
+      QualityParameter.ActualValue = new DoubleValue(quality);
+
+      return base.Apply();
+    }
+
+    public static double Calculate(ISymbolicDataAnalysisExpressionTreeInterpreter interpreter, ISymbolicExpressionTree solution, double lowerEstimationLimit, double upperEstimationLimit, IRegressionProblemData problemData, IEnumerable<int> rows, bool applyLinearScaling) {
+      IEnumerable<double> estimatedValues = interpreter.GetSymbolicExpressionTreeValues(solution, problemData.Dataset, rows);
+      IEnumerable<double> targetValues = problemData.Dataset.GetDoubleValues(problemData.TargetVariable, rows);
+      IEnumerable<double> boundedEstimatedValues = estimatedValues.LimitToRange(lowerEstimationLimit, upperEstimationLimit);
+      OnlineCalculatorError errorState;
+
+      double mse;
+      if (applyLinearScaling) {
+        var maeCalculator = new OnlineMeanAbsoluteErrorCalculator();
+        CalculateWithScaling(targetValues, boundedEstimatedValues, maeCalculator, problemData.Dataset.Rows);
+        errorState = maeCalculator.ErrorState;
+        mse = maeCalculator.MeanAbsoluteError;
+      } else
+        mse = OnlineMeanSquaredErrorCalculator.Calculate(targetValues, boundedEstimatedValues, out errorState);
+
+      if (errorState != OnlineCalculatorError.None) return Double.NaN;
+      else return mse;
+    }
+
+    public override double Evaluate(IExecutionContext context, ISymbolicExpressionTree tree, IRegressionProblemData problemData, IEnumerable<int> rows) {
+      SymbolicDataAnalysisTreeInterpreterParameter.ExecutionContext = context;
+      EstimationLimitsParameter.ExecutionContext = context;
+
+      double mse = Calculate(SymbolicDataAnalysisTreeInterpreterParameter.ActualValue, tree, EstimationLimitsParameter.ActualValue.Lower, EstimationLimitsParameter.ActualValue.Upper, problemData, rows, ApplyLinearScaling);
+
+      SymbolicDataAnalysisTreeInterpreterParameter.ExecutionContext = null;
+      EstimationLimitsParameter.ExecutionContext = null;
+
+      return mse;
+    }
+  }
+}
Index: /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/SingleObjective/Evaluators/SymbolicRegressionSingleObjectiveMeanSquaredErrorEvaluator.cs
===================================================================
--- /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/SingleObjective/Evaluators/SymbolicRegressionSingleObjectiveMeanSquaredErrorEvaluator.cs	(revision 7748)
+++ /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/SingleObjective/Evaluators/SymbolicRegressionSingleObjectiveMeanSquaredErrorEvaluator.cs	(revision 7748)
@@ -0,0 +1,86 @@
+﻿#region License Information
+/* HeuristicLab
+ * Copyright (C) 2002-2012 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 HeuristicLab.Common;
+using HeuristicLab.Core;
+using HeuristicLab.Data;
+using HeuristicLab.Encodings.SymbolicExpressionTreeEncoding;
+using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
+
+namespace HeuristicLab.Problems.DataAnalysis.Symbolic.Regression {
+  [Item("Mean squared error Evaluator", "Calculates the mean squared error of a symbolic regression solution.")]
+  [StorableClass]
+  public class SymbolicRegressionSingleObjectiveMeanSquaredErrorEvaluator : SymbolicRegressionSingleObjectiveEvaluator {
+    public override bool Maximization { get { return false; } }
+    [StorableConstructor]
+    protected SymbolicRegressionSingleObjectiveMeanSquaredErrorEvaluator(bool deserializing) : base(deserializing) { }
+    protected SymbolicRegressionSingleObjectiveMeanSquaredErrorEvaluator(SymbolicRegressionSingleObjectiveMeanSquaredErrorEvaluator original, Cloner cloner)
+      : base(original, cloner) {
+    }
+    public override IDeepCloneable Clone(Cloner cloner) {
+      return new SymbolicRegressionSingleObjectiveMeanSquaredErrorEvaluator(this, cloner);
+    }
+    public SymbolicRegressionSingleObjectiveMeanSquaredErrorEvaluator() : base() { }
+
+    public override IOperation Apply() {
+      var solution = SymbolicExpressionTreeParameter.ActualValue;
+      IEnumerable<int> rows = GenerateRowsToEvaluate();
+
+      double quality = Calculate(SymbolicDataAnalysisTreeInterpreterParameter.ActualValue, solution, EstimationLimitsParameter.ActualValue.Lower, EstimationLimitsParameter.ActualValue.Upper, ProblemDataParameter.ActualValue, rows, ApplyLinearScaling);
+      QualityParameter.ActualValue = new DoubleValue(quality);
+
+      return base.Apply();
+    }
+
+    public static double Calculate(ISymbolicDataAnalysisExpressionTreeInterpreter interpreter, ISymbolicExpressionTree solution, double lowerEstimationLimit, double upperEstimationLimit, IRegressionProblemData problemData, IEnumerable<int> rows, bool applyLinearScaling) {
+      IEnumerable<double> estimatedValues = interpreter.GetSymbolicExpressionTreeValues(solution, problemData.Dataset, rows);
+      IEnumerable<double> targetValues = problemData.Dataset.GetDoubleValues(problemData.TargetVariable, rows);
+      IEnumerable<double> boundedEstimatedValues = estimatedValues.LimitToRange(lowerEstimationLimit, upperEstimationLimit);
+      OnlineCalculatorError errorState;
+
+      double mse;
+      if (applyLinearScaling) {
+        var mseCalculator = new OnlineMeanSquaredErrorCalculator();
+        CalculateWithScaling(targetValues, boundedEstimatedValues, mseCalculator, problemData.Dataset.Rows);
+        errorState = mseCalculator.ErrorState;
+        mse = mseCalculator.MeanSquaredError;
+      } else
+        mse = OnlineMeanSquaredErrorCalculator.Calculate(targetValues, boundedEstimatedValues, out errorState);
+
+      if (errorState != OnlineCalculatorError.None) return Double.NaN;
+      else return mse;
+    }
+
+    public override double Evaluate(IExecutionContext context, ISymbolicExpressionTree tree, IRegressionProblemData problemData, IEnumerable<int> rows) {
+      SymbolicDataAnalysisTreeInterpreterParameter.ExecutionContext = context;
+      EstimationLimitsParameter.ExecutionContext = context;
+
+      double mse = Calculate(SymbolicDataAnalysisTreeInterpreterParameter.ActualValue, tree, EstimationLimitsParameter.ActualValue.Lower, EstimationLimitsParameter.ActualValue.Upper, problemData, rows, ApplyLinearScaling);
+
+      SymbolicDataAnalysisTreeInterpreterParameter.ExecutionContext = null;
+      EstimationLimitsParameter.ExecutionContext = null;
+
+      return mse;
+    }
+  }
+}
Index: /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/SingleObjective/Evaluators/SymbolicRegressionSingleObjectivePearsonRSquaredEvaluator.cs
===================================================================
--- /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/SingleObjective/Evaluators/SymbolicRegressionSingleObjectivePearsonRSquaredEvaluator.cs	(revision 7748)
+++ /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/SingleObjective/Evaluators/SymbolicRegressionSingleObjectivePearsonRSquaredEvaluator.cs	(revision 7748)
@@ -0,0 +1,77 @@
+﻿#region License Information
+/* HeuristicLab
+ * Copyright (C) 2002-2012 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.Collections.Generic;
+using HeuristicLab.Common;
+using HeuristicLab.Core;
+using HeuristicLab.Data;
+using HeuristicLab.Encodings.SymbolicExpressionTreeEncoding;
+using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
+
+namespace HeuristicLab.Problems.DataAnalysis.Symbolic.Regression {
+  [Item("Pearson R² Evaluator", "Calculates the square of the pearson correlation coefficient (also known as coefficient of determination) of a symbolic regression solution.")]
+  [StorableClass]
+  public class SymbolicRegressionSingleObjectivePearsonRSquaredEvaluator : SymbolicRegressionSingleObjectiveEvaluator {
+    [StorableConstructor]
+    protected SymbolicRegressionSingleObjectivePearsonRSquaredEvaluator(bool deserializing) : base(deserializing) { }
+    protected SymbolicRegressionSingleObjectivePearsonRSquaredEvaluator(SymbolicRegressionSingleObjectivePearsonRSquaredEvaluator original, Cloner cloner)
+      : base(original, cloner) {
+    }
+    public override IDeepCloneable Clone(Cloner cloner) {
+      return new SymbolicRegressionSingleObjectivePearsonRSquaredEvaluator(this, cloner);
+    }
+
+    public SymbolicRegressionSingleObjectivePearsonRSquaredEvaluator() : base() { }
+
+    public override bool Maximization { get { return true; } }
+
+    public override IOperation Apply() {
+      var solution = SymbolicExpressionTreeParameter.ActualValue;
+      IEnumerable<int> rows = GenerateRowsToEvaluate();
+
+      double quality = Calculate(SymbolicDataAnalysisTreeInterpreterParameter.ActualValue, solution, EstimationLimitsParameter.ActualValue.Lower, EstimationLimitsParameter.ActualValue.Upper, ProblemDataParameter.ActualValue, rows);
+      QualityParameter.ActualValue = new DoubleValue(quality);
+
+      return base.Apply();
+    }
+
+    public static double Calculate(ISymbolicDataAnalysisExpressionTreeInterpreter interpreter, ISymbolicExpressionTree solution, double lowerEstimationLimit, double upperEstimationLimit, IRegressionProblemData problemData, IEnumerable<int> rows) {
+      IEnumerable<double> estimatedValues = interpreter.GetSymbolicExpressionTreeValues(solution, problemData.Dataset, rows);
+      IEnumerable<double> originalValues = problemData.Dataset.GetDoubleValues(problemData.TargetVariable, rows);
+      OnlineCalculatorError errorState;
+      double r2 = OnlinePearsonsRSquaredCalculator.Calculate(estimatedValues, originalValues, out errorState);
+      if (errorState != OnlineCalculatorError.None) return 0.0;
+      else return r2;
+    }
+
+    public override double Evaluate(IExecutionContext context, ISymbolicExpressionTree tree, IRegressionProblemData problemData, IEnumerable<int> rows) {
+      SymbolicDataAnalysisTreeInterpreterParameter.ExecutionContext = context;
+      EstimationLimitsParameter.ExecutionContext = context;
+
+      double r2 = Calculate(SymbolicDataAnalysisTreeInterpreterParameter.ActualValue, tree, EstimationLimitsParameter.ActualValue.Lower, EstimationLimitsParameter.ActualValue.Upper, problemData, rows);
+
+      SymbolicDataAnalysisTreeInterpreterParameter.ExecutionContext = null;
+      EstimationLimitsParameter.ExecutionContext = null;
+
+      return r2;
+    }
+  }
+}
Index: /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/SingleObjective/SymbolicRegressionSingleObjectiveOverfittingAnalyzer.cs
===================================================================
--- /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/SingleObjective/SymbolicRegressionSingleObjectiveOverfittingAnalyzer.cs	(revision 7748)
+++ /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/SingleObjective/SymbolicRegressionSingleObjectiveOverfittingAnalyzer.cs	(revision 7748)
@@ -0,0 +1,122 @@
+#region License Information
+/* HeuristicLab
+ * Copyright (C) 2002-2012 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.Collections.Generic;
+using System.Linq;
+using HeuristicLab.Analysis;
+using HeuristicLab.Common;
+using HeuristicLab.Core;
+using HeuristicLab.Data;
+using HeuristicLab.Optimization;
+using HeuristicLab.Parameters;
+using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
+
+namespace HeuristicLab.Problems.DataAnalysis.Symbolic.Regression {
+  [Item("SymbolicRegressionSingleObjectiveOverfittingAnalyzer", "Calculates and tracks correlation of training and validation fitness of symbolic regression models.")]
+  [StorableClass]
+  public sealed class SymbolicRegressionSingleObjectiveOverfittingAnalyzer : SymbolicDataAnalysisSingleObjectiveValidationAnalyzer<ISymbolicRegressionSingleObjectiveEvaluator, IRegressionProblemData> {
+    private const string TrainingValidationCorrelationParameterName = "Training and validation fitness correlation";
+    private const string TrainingValidationCorrelationTableParameterName = "Training and validation fitness correlation table";
+    private const string LowerCorrelationThresholdParameterName = "LowerCorrelationThreshold";
+    private const string UpperCorrelationThresholdParameterName = "UpperCorrelationThreshold";
+    private const string OverfittingParameterName = "IsOverfitting";
+
+    #region parameter properties
+    public ILookupParameter<DoubleValue> TrainingValidationQualityCorrelationParameter {
+      get { return (ILookupParameter<DoubleValue>)Parameters[TrainingValidationCorrelationParameterName]; }
+    }
+    public ILookupParameter<DataTable> TrainingValidationQualityCorrelationTableParameter {
+      get { return (ILookupParameter<DataTable>)Parameters[TrainingValidationCorrelationTableParameterName]; }
+    }
+    public IValueLookupParameter<DoubleValue> LowerCorrelationThresholdParameter {
+      get { return (IValueLookupParameter<DoubleValue>)Parameters[LowerCorrelationThresholdParameterName]; }
+    }
+    public IValueLookupParameter<DoubleValue> UpperCorrelationThresholdParameter {
+      get { return (IValueLookupParameter<DoubleValue>)Parameters[UpperCorrelationThresholdParameterName]; }
+    }
+    public ILookupParameter<BoolValue> OverfittingParameter {
+      get { return (ILookupParameter<BoolValue>)Parameters[OverfittingParameterName]; }
+    }
+    #endregion
+
+    [StorableConstructor]
+    private SymbolicRegressionSingleObjectiveOverfittingAnalyzer(bool deserializing) : base(deserializing) { }
+    private SymbolicRegressionSingleObjectiveOverfittingAnalyzer(SymbolicRegressionSingleObjectiveOverfittingAnalyzer original, Cloner cloner) : base(original, cloner) { }
+    public SymbolicRegressionSingleObjectiveOverfittingAnalyzer()
+      : base() {
+      Parameters.Add(new LookupParameter<DoubleValue>(TrainingValidationCorrelationParameterName, "Correlation of training and validation fitnesses"));
+      Parameters.Add(new LookupParameter<DataTable>(TrainingValidationCorrelationTableParameterName, "Data table of training and validation fitness correlation values over the whole run."));
+      Parameters.Add(new ValueLookupParameter<DoubleValue>(LowerCorrelationThresholdParameterName, "Lower threshold for correlation value that marks the boundary from non-overfitting to overfitting.", new DoubleValue(0.65)));
+      Parameters.Add(new ValueLookupParameter<DoubleValue>(UpperCorrelationThresholdParameterName, "Upper threshold for correlation value that marks the boundary from overfitting to non-overfitting.", new DoubleValue(0.75)));
+      Parameters.Add(new LookupParameter<BoolValue>(OverfittingParameterName, "Boolean indicator for overfitting."));
+    }
+
+    public override IDeepCloneable Clone(Cloner cloner) {
+      return new SymbolicRegressionSingleObjectiveOverfittingAnalyzer(this, cloner);
+    }
+
+    public override IOperation Apply() {
+      IEnumerable<int> rows = GenerateRowsToEvaluate();
+      if (!rows.Any()) return base.Apply();
+
+      double[] trainingQuality = QualityParameter.ActualValue.Select(x => x.Value).ToArray();
+      var problemData = ProblemDataParameter.ActualValue;
+      var evaluator = EvaluatorParameter.ActualValue;
+      // evaluate on validation partition
+      IExecutionContext childContext = (IExecutionContext)ExecutionContext.CreateChildOperation(evaluator);
+      double[] validationQuality = SymbolicExpressionTree
+        .AsParallel()
+        .Select(t => evaluator.Evaluate(childContext, t, problemData, rows))
+        .ToArray();
+      double r = 0.0;
+      try {
+        r = alglib.spearmancorr2(trainingQuality, validationQuality);
+      }
+      catch (alglib.alglibexception) {
+        r = 0.0;
+      }
+
+      TrainingValidationQualityCorrelationParameter.ActualValue = new DoubleValue(r);
+
+      if (TrainingValidationQualityCorrelationTableParameter.ActualValue == null) {
+        var dataTable = new DataTable(TrainingValidationQualityCorrelationTableParameter.Name, TrainingValidationQualityCorrelationTableParameter.Description);
+        dataTable.Rows.Add(new DataRow(TrainingValidationQualityCorrelationParameter.Name, TrainingValidationQualityCorrelationParameter.Description));
+        dataTable.Rows[TrainingValidationQualityCorrelationParameter.Name].VisualProperties.StartIndexZero = true;
+        TrainingValidationQualityCorrelationTableParameter.ActualValue = dataTable;
+        ResultCollectionParameter.ActualValue.Add(new Result(TrainingValidationQualityCorrelationTableParameter.Name, dataTable));
+      }
+
+      TrainingValidationQualityCorrelationTableParameter.ActualValue.Rows[TrainingValidationQualityCorrelationParameter.Name].Values.Add(r);
+
+      if (OverfittingParameter.ActualValue != null && OverfittingParameter.ActualValue.Value) {
+        // overfitting == true
+        // => r must reach the upper threshold to switch back to non-overfitting state
+        OverfittingParameter.ActualValue = new BoolValue(r < UpperCorrelationThresholdParameter.ActualValue.Value);
+      } else {
+        // overfitting == false 
+        // => r must drop below lower threshold to switch to overfitting state
+        OverfittingParameter.ActualValue = new BoolValue(r < LowerCorrelationThresholdParameter.ActualValue.Value);
+      }
+
+      return base.Apply();
+    }
+  }
+}
Index: /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/SingleObjective/SymbolicRegressionSingleObjectiveProblem.cs
===================================================================
--- /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/SingleObjective/SymbolicRegressionSingleObjectiveProblem.cs	(revision 7748)
+++ /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/SingleObjective/SymbolicRegressionSingleObjectiveProblem.cs	(revision 7748)
@@ -0,0 +1,119 @@
+﻿#region License Information
+/* HeuristicLab
+ * Copyright (C) 2002-2012 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.Linq;
+using HeuristicLab.Common;
+using HeuristicLab.Core;
+using HeuristicLab.Parameters;
+using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
+
+namespace HeuristicLab.Problems.DataAnalysis.Symbolic.Regression {
+  [Item("Symbolic Regression Problem (single objective)", "Represents a single objective symbolic regression problem.")]
+  [StorableClass]
+  [Creatable("Problems")]
+  public class SymbolicRegressionSingleObjectiveProblem : SymbolicDataAnalysisSingleObjectiveProblem<IRegressionProblemData, ISymbolicRegressionSingleObjectiveEvaluator, ISymbolicDataAnalysisSolutionCreator>, IRegressionProblem {
+    private const double PunishmentFactor = 10;
+    private const int InitialMaximumTreeDepth = 8;
+    private const int InitialMaximumTreeLength = 25;
+    private const string EstimationLimitsParameterName = "EstimationLimits";
+    private const string EstimationLimitsParameterDescription = "The limits for the estimated value that can be returned by the symbolic regression model.";
+
+    #region parameter properties
+    public IFixedValueParameter<DoubleLimit> EstimationLimitsParameter {
+      get { return (IFixedValueParameter<DoubleLimit>)Parameters[EstimationLimitsParameterName]; }
+    }
+    #endregion
+    #region properties
+    public DoubleLimit EstimationLimits {
+      get { return EstimationLimitsParameter.Value; }
+    }
+    #endregion
+    [StorableConstructor]
+    protected SymbolicRegressionSingleObjectiveProblem(bool deserializing) : base(deserializing) { }
+    protected SymbolicRegressionSingleObjectiveProblem(SymbolicRegressionSingleObjectiveProblem original, Cloner cloner) : base(original, cloner) { }
+    public override IDeepCloneable Clone(Cloner cloner) { return new SymbolicRegressionSingleObjectiveProblem(this, cloner); }
+
+    public SymbolicRegressionSingleObjectiveProblem()
+      : base(new RegressionProblemData(), new SymbolicRegressionSingleObjectivePearsonRSquaredEvaluator(), new SymbolicDataAnalysisExpressionTreeCreator()) {
+      Parameters.Add(new FixedValueParameter<DoubleLimit>(EstimationLimitsParameterName, EstimationLimitsParameterDescription));
+
+      EstimationLimitsParameter.Hidden = true;
+
+      Maximization.Value = true;
+      MaximumSymbolicExpressionTreeDepth.Value = InitialMaximumTreeDepth;
+      MaximumSymbolicExpressionTreeLength.Value = InitialMaximumTreeLength;
+
+      SymbolicExpressionTreeGrammarParameter.ValueChanged += (o, e) => ConfigureGrammarSymbols();
+
+      ConfigureGrammarSymbols();
+      InitializeOperators();
+      UpdateEstimationLimits();
+    }
+
+    private void ConfigureGrammarSymbols() {
+      var grammar = SymbolicExpressionTreeGrammar as TypeCoherentExpressionGrammar;
+      if (grammar != null) grammar.ConfigureAsDefaultRegressionGrammar();
+    }
+
+    private void InitializeOperators() {
+      Operators.Add(new SymbolicRegressionSingleObjectiveTrainingBestSolutionAnalyzer());
+      Operators.Add(new SymbolicRegressionSingleObjectiveValidationBestSolutionAnalyzer());
+      Operators.Add(new SymbolicRegressionSingleObjectiveOverfittingAnalyzer());
+      Operators.Add(new SymbolicRegressionSingleObjectiveTrainingParetoBestSolutionAnalyzer());
+      Operators.Add(new SymbolicRegressionSingleObjectiveValidationParetoBestSolutionAnalyzer());
+
+      ParameterizeOperators();
+    }
+
+    private void UpdateEstimationLimits() {
+      if (ProblemData.TrainingIndizes.Any()) {
+        var targetValues = ProblemData.Dataset.GetDoubleValues(ProblemData.TargetVariable, ProblemData.TrainingIndizes).ToList();
+        var mean = targetValues.Average();
+        var range = targetValues.Max() - targetValues.Min();
+        EstimationLimits.Upper = mean + PunishmentFactor * range;
+        EstimationLimits.Lower = mean - PunishmentFactor * range;
+      } else {
+        EstimationLimits.Upper = double.MaxValue;
+        EstimationLimits.Lower = double.MinValue;
+      }
+    }
+
+    protected override void OnProblemDataChanged() {
+      base.OnProblemDataChanged();
+      UpdateEstimationLimits();
+    }
+
+    protected override void ParameterizeOperators() {
+      base.ParameterizeOperators();
+      if (Parameters.ContainsKey(EstimationLimitsParameterName)) {
+        var operators = Parameters.OfType<IValueParameter>().Select(p => p.Value).OfType<IOperator>().Union(Operators);
+        foreach (var op in operators.OfType<ISymbolicDataAnalysisBoundedOperator>()) {
+          op.EstimationLimitsParameter.ActualName = EstimationLimitsParameter.Name;
+        }
+      }
+    }
+
+    public override void ImportProblemDataFromFile(string fileName) {
+      RegressionProblemData problemData = RegressionProblemData.ImportFromFile(fileName);
+      ProblemData = problemData;
+    }
+  }
+}
Index: /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/SingleObjective/SymbolicRegressionSingleObjectiveTrainingBestSolutionAnalyzer.cs
===================================================================
--- /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/SingleObjective/SymbolicRegressionSingleObjectiveTrainingBestSolutionAnalyzer.cs	(revision 7748)
+++ /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/SingleObjective/SymbolicRegressionSingleObjectiveTrainingBestSolutionAnalyzer.cs	(revision 7748)
@@ -0,0 +1,83 @@
+#region License Information
+/* HeuristicLab
+ * Copyright (C) 2002-2012 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 HeuristicLab.Common;
+using HeuristicLab.Core;
+using HeuristicLab.Data;
+using HeuristicLab.Encodings.SymbolicExpressionTreeEncoding;
+using HeuristicLab.Parameters;
+using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
+
+namespace HeuristicLab.Problems.DataAnalysis.Symbolic.Regression {
+  /// <summary>
+  /// An operator that analyzes the training best symbolic regression solution for single objective symbolic regression problems.
+  /// </summary>
+  [Item("SymbolicRegressionSingleObjectiveTrainingBestSolutionAnalyzer", "An operator that analyzes the training best symbolic regression solution for single objective symbolic regression problems.")]
+  [StorableClass]
+  public sealed class SymbolicRegressionSingleObjectiveTrainingBestSolutionAnalyzer : SymbolicDataAnalysisSingleObjectiveTrainingBestSolutionAnalyzer<ISymbolicRegressionSolution>,
+  ISymbolicDataAnalysisInterpreterOperator, ISymbolicDataAnalysisBoundedOperator {
+    private const string ProblemDataParameterName = "ProblemData";
+    private const string SymbolicDataAnalysisTreeInterpreterParameterName = "SymbolicDataAnalysisTreeInterpreter";
+    private const string EstimationLimitsParameterName = "EstimationLimits";
+    private const string ApplyLinearScalingParameterName = "ApplyLinearScaling";
+    #region parameter properties
+    public ILookupParameter<IRegressionProblemData> ProblemDataParameter {
+      get { return (ILookupParameter<IRegressionProblemData>)Parameters[ProblemDataParameterName]; }
+    }
+    public ILookupParameter<ISymbolicDataAnalysisExpressionTreeInterpreter> SymbolicDataAnalysisTreeInterpreterParameter {
+      get { return (ILookupParameter<ISymbolicDataAnalysisExpressionTreeInterpreter>)Parameters[SymbolicDataAnalysisTreeInterpreterParameterName]; }
+    }
+    public IValueLookupParameter<DoubleLimit> EstimationLimitsParameter {
+      get { return (IValueLookupParameter<DoubleLimit>)Parameters[EstimationLimitsParameterName]; }
+    }
+    public IValueParameter<BoolValue> ApplyLinearScalingParameter {
+      get { return (IValueParameter<BoolValue>)Parameters[ApplyLinearScalingParameterName]; }
+    }
+    #endregion
+
+    #region properties
+    public BoolValue ApplyLinearScaling {
+      get { return ApplyLinearScalingParameter.Value; }
+    }
+    #endregion
+
+    [StorableConstructor]
+    private SymbolicRegressionSingleObjectiveTrainingBestSolutionAnalyzer(bool deserializing) : base(deserializing) { }
+    private SymbolicRegressionSingleObjectiveTrainingBestSolutionAnalyzer(SymbolicRegressionSingleObjectiveTrainingBestSolutionAnalyzer original, Cloner cloner) : base(original, cloner) { }
+    public SymbolicRegressionSingleObjectiveTrainingBestSolutionAnalyzer()
+      : base() {
+      Parameters.Add(new LookupParameter<IRegressionProblemData>(ProblemDataParameterName, "The problem data for the symbolic regression solution."));
+      Parameters.Add(new LookupParameter<ISymbolicDataAnalysisExpressionTreeInterpreter>(SymbolicDataAnalysisTreeInterpreterParameterName, "The symbolic data analysis tree interpreter for the symbolic expression tree."));
+      Parameters.Add(new ValueLookupParameter<DoubleLimit>(EstimationLimitsParameterName, "The lower and upper limit for the estimated values produced by the symbolic regression model."));
+      Parameters.Add(new ValueParameter<BoolValue>(ApplyLinearScalingParameterName, "Flag that indicates if the produced symbolic regression solution should be linearly scaled.", new BoolValue(true)));
+    }
+    public override IDeepCloneable Clone(Cloner cloner) {
+      return new SymbolicRegressionSingleObjectiveTrainingBestSolutionAnalyzer(this, cloner);
+    }
+
+    protected override ISymbolicRegressionSolution CreateSolution(ISymbolicExpressionTree bestTree, double bestQuality) {
+      var model = new SymbolicRegressionModel((ISymbolicExpressionTree)bestTree.Clone(), SymbolicDataAnalysisTreeInterpreterParameter.ActualValue, EstimationLimitsParameter.ActualValue.Lower, EstimationLimitsParameter.ActualValue.Upper);
+      if (ApplyLinearScaling.Value)
+        SymbolicRegressionModel.Scale(model, ProblemDataParameter.ActualValue);
+      return new SymbolicRegressionSolution(model, (IRegressionProblemData)ProblemDataParameter.ActualValue.Clone());
+    }
+  }
+}
Index: /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/SingleObjective/SymbolicRegressionSingleObjectiveTrainingParetoBestSolutionAnalyzer.cs
===================================================================
--- /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/SingleObjective/SymbolicRegressionSingleObjectiveTrainingParetoBestSolutionAnalyzer.cs	(revision 7748)
+++ /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/SingleObjective/SymbolicRegressionSingleObjectiveTrainingParetoBestSolutionAnalyzer.cs	(revision 7748)
@@ -0,0 +1,83 @@
+#region License Information
+/* HeuristicLab
+ * Copyright (C) 2002-2012 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 HeuristicLab.Common;
+using HeuristicLab.Core;
+using HeuristicLab.Data;
+using HeuristicLab.Encodings.SymbolicExpressionTreeEncoding;
+using HeuristicLab.Parameters;
+using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
+
+namespace HeuristicLab.Problems.DataAnalysis.Symbolic.Regression {
+  /// <summary>
+  /// An operator that collects the training Pareto-best symbolic regression solutions for single objective symbolic regression problems.
+  /// </summary>
+  [Item("SymbolicRegressionSingleObjectiveTrainingParetoBestSolutionAnalyzer", "An operator that collects the training Pareto-best symbolic regression solutions for single objective symbolic regression problems.")]
+  [StorableClass]
+  public sealed class SymbolicRegressionSingleObjectiveTrainingParetoBestSolutionAnalyzer : SymbolicDataAnalysisSingleObjectiveTrainingParetoBestSolutionAnalyzer<ISymbolicRegressionSolution>,
+  ISymbolicDataAnalysisInterpreterOperator, ISymbolicDataAnalysisBoundedOperator {
+    private const string ProblemDataParameterName = "ProblemData";
+    private const string SymbolicDataAnalysisTreeInterpreterParameterName = "SymbolicDataAnalysisTreeInterpreter";
+    private const string EstimationLimitsParameterName = "EstimationLimits";
+    private const string ApplyLinearScalingParameterName = "ApplyLinearScaling";
+    #region parameter properties
+    public ILookupParameter<IRegressionProblemData> ProblemDataParameter {
+      get { return (ILookupParameter<IRegressionProblemData>)Parameters[ProblemDataParameterName]; }
+    }
+    public ILookupParameter<ISymbolicDataAnalysisExpressionTreeInterpreter> SymbolicDataAnalysisTreeInterpreterParameter {
+      get { return (ILookupParameter<ISymbolicDataAnalysisExpressionTreeInterpreter>)Parameters[SymbolicDataAnalysisTreeInterpreterParameterName]; }
+    }
+    public IValueLookupParameter<DoubleLimit> EstimationLimitsParameter {
+      get { return (IValueLookupParameter<DoubleLimit>)Parameters[EstimationLimitsParameterName]; }
+    }
+    public IValueParameter<BoolValue> ApplyLinearScalingParameter {
+      get { return (IValueParameter<BoolValue>)Parameters[ApplyLinearScalingParameterName]; }
+    }
+    #endregion
+
+    #region properties
+    public BoolValue ApplyLinearScaling {
+      get { return ApplyLinearScalingParameter.Value; }
+    }
+    #endregion
+
+    [StorableConstructor]
+    private SymbolicRegressionSingleObjectiveTrainingParetoBestSolutionAnalyzer(bool deserializing) : base(deserializing) { }
+    private SymbolicRegressionSingleObjectiveTrainingParetoBestSolutionAnalyzer(SymbolicRegressionSingleObjectiveTrainingParetoBestSolutionAnalyzer original, Cloner cloner) : base(original, cloner) { }
+    public SymbolicRegressionSingleObjectiveTrainingParetoBestSolutionAnalyzer()
+      : base() {
+      Parameters.Add(new LookupParameter<IRegressionProblemData>(ProblemDataParameterName, "The problem data for the symbolic regression solution."));
+      Parameters.Add(new LookupParameter<ISymbolicDataAnalysisExpressionTreeInterpreter>(SymbolicDataAnalysisTreeInterpreterParameterName, "The symbolic data analysis tree interpreter for the symbolic expression tree."));
+      Parameters.Add(new ValueLookupParameter<DoubleLimit>(EstimationLimitsParameterName, "The lower and upper limit for the estimated values produced by the symbolic regression model."));
+      Parameters.Add(new ValueParameter<BoolValue>(ApplyLinearScalingParameterName, "Flag that indicates if the produced symbolic regression solution should be linearly scaled.", new BoolValue(true)));
+    }
+    public override IDeepCloneable Clone(Cloner cloner) {
+      return new SymbolicRegressionSingleObjectiveTrainingParetoBestSolutionAnalyzer(this, cloner);
+    }
+
+    protected override ISymbolicRegressionSolution CreateSolution(ISymbolicExpressionTree bestTree) {
+      var model = new SymbolicRegressionModel((ISymbolicExpressionTree)bestTree.Clone(), SymbolicDataAnalysisTreeInterpreterParameter.ActualValue, EstimationLimitsParameter.ActualValue.Lower, EstimationLimitsParameter.ActualValue.Upper);
+      if (ApplyLinearScaling.Value)
+        SymbolicRegressionModel.Scale(model, ProblemDataParameter.ActualValue);
+      return new SymbolicRegressionSolution(model, (IRegressionProblemData)ProblemDataParameter.ActualValue.Clone());
+    }
+  }
+}
Index: /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/SingleObjective/SymbolicRegressionSingleObjectiveValidationBestSolutionAnalyzer.cs
===================================================================
--- /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/SingleObjective/SymbolicRegressionSingleObjectiveValidationBestSolutionAnalyzer.cs	(revision 7748)
+++ /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/SingleObjective/SymbolicRegressionSingleObjectiveValidationBestSolutionAnalyzer.cs	(revision 7748)
@@ -0,0 +1,75 @@
+#region License Information
+/* HeuristicLab
+ * Copyright (C) 2002-2012 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 HeuristicLab.Common;
+using HeuristicLab.Core;
+using HeuristicLab.Data;
+using HeuristicLab.Encodings.SymbolicExpressionTreeEncoding;
+using HeuristicLab.Parameters;
+using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
+
+namespace HeuristicLab.Problems.DataAnalysis.Symbolic.Regression {
+  /// <summary>
+  /// An operator that analyzes the validation best symbolic regression solution for single objective symbolic regression problems.
+  /// </summary>
+  [Item("SymbolicRegressionSingleObjectiveValidationBestSolutionAnalyzer", "An operator that analyzes the validation best symbolic regression solution for single objective symbolic regression problems.")]
+  [StorableClass]
+  public sealed class SymbolicRegressionSingleObjectiveValidationBestSolutionAnalyzer : SymbolicDataAnalysisSingleObjectiveValidationBestSolutionAnalyzer<ISymbolicRegressionSolution, ISymbolicRegressionSingleObjectiveEvaluator, IRegressionProblemData>,
+    ISymbolicDataAnalysisBoundedOperator {
+    private const string EstimationLimitsParameterName = "EstimationLimits";
+    private const string ApplyLinearScalingParameterName = "ApplyLinearScaling";
+
+    #region parameter properties
+    public IValueLookupParameter<DoubleLimit> EstimationLimitsParameter {
+      get { return (IValueLookupParameter<DoubleLimit>)Parameters[EstimationLimitsParameterName]; }
+    }
+    public IValueParameter<BoolValue> ApplyLinearScalingParameter {
+      get { return (IValueParameter<BoolValue>)Parameters[ApplyLinearScalingParameterName]; }
+    }
+    #endregion
+
+    #region properties
+    public BoolValue ApplyLinearScaling {
+      get { return ApplyLinearScalingParameter.Value; }
+    }
+    #endregion
+
+    [StorableConstructor]
+    private SymbolicRegressionSingleObjectiveValidationBestSolutionAnalyzer(bool deserializing) : base(deserializing) { }
+    private SymbolicRegressionSingleObjectiveValidationBestSolutionAnalyzer(SymbolicRegressionSingleObjectiveValidationBestSolutionAnalyzer original, Cloner cloner) : base(original, cloner) { }
+    public SymbolicRegressionSingleObjectiveValidationBestSolutionAnalyzer()
+      : base() {
+      Parameters.Add(new ValueLookupParameter<DoubleLimit>(EstimationLimitsParameterName, "The lower and upper limit for the estimated values produced by the symbolic regression model."));
+      Parameters.Add(new ValueParameter<BoolValue>(ApplyLinearScalingParameterName, "Flag that indicates if the produced symbolic regression solution should be linearly scaled.", new BoolValue(true)));
+    }
+
+    public override IDeepCloneable Clone(Cloner cloner) {
+      return new SymbolicRegressionSingleObjectiveValidationBestSolutionAnalyzer(this, cloner);
+    }
+
+    protected override ISymbolicRegressionSolution CreateSolution(ISymbolicExpressionTree bestTree, double bestQuality) {
+      var model = new SymbolicRegressionModel((ISymbolicExpressionTree)bestTree.Clone(), SymbolicDataAnalysisTreeInterpreterParameter.ActualValue, EstimationLimitsParameter.ActualValue.Lower, EstimationLimitsParameter.ActualValue.Upper);
+      if (ApplyLinearScaling.Value)
+        SymbolicRegressionModel.Scale(model, ProblemDataParameter.ActualValue);
+      return new SymbolicRegressionSolution(model, (IRegressionProblemData)ProblemDataParameter.ActualValue.Clone());
+    }
+  }
+}
Index: /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/SingleObjective/SymbolicRegressionSingleObjectiveValidationParetoBestSolutionAnalyzer.cs
===================================================================
--- /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/SingleObjective/SymbolicRegressionSingleObjectiveValidationParetoBestSolutionAnalyzer.cs	(revision 7748)
+++ /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/SingleObjective/SymbolicRegressionSingleObjectiveValidationParetoBestSolutionAnalyzer.cs	(revision 7748)
@@ -0,0 +1,73 @@
+#region License Information
+/* HeuristicLab
+ * Copyright (C) 2002-2012 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 HeuristicLab.Common;
+using HeuristicLab.Core;
+using HeuristicLab.Data;
+using HeuristicLab.Encodings.SymbolicExpressionTreeEncoding;
+using HeuristicLab.Parameters;
+using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
+
+namespace HeuristicLab.Problems.DataAnalysis.Symbolic.Regression {
+  /// <summary>
+  /// An operator that collects the validation Pareto-best symbolic regression solutions for single objective symbolic regression problems.
+  /// </summary>
+  [Item("SymbolicRegressionSingleObjectiveValidationParetoBestSolutionAnalyzer", "An operator that collects the validation Pareto-best symbolic regression solutions for single objective symbolic regression problems.")]
+  [StorableClass]
+  public sealed class SymbolicRegressionSingleObjectiveValidationParetoBestSolutionAnalyzer : SymbolicDataAnalysisSingleObjectiveValidationParetoBestSolutionAnalyzer<ISymbolicRegressionSolution, ISymbolicRegressionSingleObjectiveEvaluator, IRegressionProblemData>,
+  ISymbolicDataAnalysisInterpreterOperator, ISymbolicDataAnalysisBoundedOperator {
+    private const string EstimationLimitsParameterName = "EstimationLimits";
+    private const string ApplyLinearScalingParameterName = "ApplyLinearScaling";
+    #region parameter properties
+    public IValueLookupParameter<DoubleLimit> EstimationLimitsParameter {
+      get { return (IValueLookupParameter<DoubleLimit>)Parameters[EstimationLimitsParameterName]; }
+    }
+    public IValueParameter<BoolValue> ApplyLinearScalingParameter {
+      get { return (IValueParameter<BoolValue>)Parameters[ApplyLinearScalingParameterName]; }
+    }
+    #endregion
+
+    #region properties
+    public BoolValue ApplyLinearScaling {
+      get { return ApplyLinearScalingParameter.Value; }
+    }
+    #endregion
+
+    [StorableConstructor]
+    private SymbolicRegressionSingleObjectiveValidationParetoBestSolutionAnalyzer(bool deserializing) : base(deserializing) { }
+    private SymbolicRegressionSingleObjectiveValidationParetoBestSolutionAnalyzer(SymbolicRegressionSingleObjectiveValidationParetoBestSolutionAnalyzer original, Cloner cloner) : base(original, cloner) { }
+    public SymbolicRegressionSingleObjectiveValidationParetoBestSolutionAnalyzer()
+      : base() {
+      Parameters.Add(new ValueLookupParameter<DoubleLimit>(EstimationLimitsParameterName, "The lower and upper limit for the estimated values produced by the symbolic regression model."));
+      Parameters.Add(new ValueParameter<BoolValue>(ApplyLinearScalingParameterName, "Flag that indicates if the produced symbolic regression solution should be linearly scaled.", new BoolValue(true)));
+    }
+    public override IDeepCloneable Clone(Cloner cloner) {
+      return new SymbolicRegressionSingleObjectiveValidationParetoBestSolutionAnalyzer(this, cloner);
+    }
+
+    protected override ISymbolicRegressionSolution CreateSolution(ISymbolicExpressionTree bestTree) {
+      var model = new SymbolicRegressionModel((ISymbolicExpressionTree)bestTree.Clone(), SymbolicDataAnalysisTreeInterpreterParameter.ActualValue, EstimationLimitsParameter.ActualValue.Lower, EstimationLimitsParameter.ActualValue.Upper);
+      if (ApplyLinearScaling.Value)
+        SymbolicRegressionModel.Scale(model, ProblemDataParameter.ActualValue);
+      return new SymbolicRegressionSolution(model, (IRegressionProblemData)ProblemDataParameter.ActualValue.Clone());
+    }
+  }
+}
Index: /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/SymbolicRegressionModel.cs
===================================================================
--- /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/SymbolicRegressionModel.cs	(revision 7748)
+++ /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/SymbolicRegressionModel.cs	(revision 7748)
@@ -0,0 +1,141 @@
+#region License Information
+/* HeuristicLab
+ * Copyright (C) 2002-2012 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.Collections.Generic;
+using HeuristicLab.Common;
+using HeuristicLab.Core;
+using HeuristicLab.Encodings.SymbolicExpressionTreeEncoding;
+using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
+
+namespace HeuristicLab.Problems.DataAnalysis.Symbolic.Regression {
+  /// <summary>
+  /// Represents a symbolic regression model
+  /// </summary>
+  [StorableClass]
+  [Item(Name = "Symbolic Regression Model", Description = "Represents a symbolic regression model.")]
+  public class SymbolicRegressionModel : SymbolicDataAnalysisModel, ISymbolicRegressionModel {
+    [Storable]
+    private double lowerEstimationLimit;
+    [Storable]
+    private double upperEstimationLimit;
+
+    [StorableConstructor]
+    protected SymbolicRegressionModel(bool deserializing) : base(deserializing) { }
+    protected SymbolicRegressionModel(SymbolicRegressionModel original, Cloner cloner)
+      : base(original, cloner) {
+      this.lowerEstimationLimit = original.lowerEstimationLimit;
+      this.upperEstimationLimit = original.upperEstimationLimit;
+    }
+    public SymbolicRegressionModel(ISymbolicExpressionTree tree, ISymbolicDataAnalysisExpressionTreeInterpreter interpreter,
+      double lowerEstimationLimit = double.MinValue, double upperEstimationLimit = double.MaxValue)
+      : base(tree, interpreter) {
+      this.lowerEstimationLimit = lowerEstimationLimit;
+      this.upperEstimationLimit = upperEstimationLimit;
+    }
+
+    public override IDeepCloneable Clone(Cloner cloner) {
+      return new SymbolicRegressionModel(this, cloner);
+    }
+
+    public IEnumerable<double> GetEstimatedValues(Dataset dataset, IEnumerable<int> rows) {
+      return Interpreter.GetSymbolicExpressionTreeValues(SymbolicExpressionTree, dataset, rows)
+        .LimitToRange(lowerEstimationLimit, upperEstimationLimit);
+    }
+
+    public ISymbolicRegressionSolution CreateRegressionSolution(IRegressionProblemData problemData) {
+      return new SymbolicRegressionSolution(this, problemData);
+    }
+    IRegressionSolution IRegressionModel.CreateRegressionSolution(IRegressionProblemData problemData) {
+      return CreateRegressionSolution(problemData);
+    }
+
+    public static void Scale(SymbolicRegressionModel model, IRegressionProblemData problemData) {
+      var dataset = problemData.Dataset;
+      var targetVariable = problemData.TargetVariable;
+      var rows = problemData.TrainingIndizes;
+      var estimatedValues = model.Interpreter.GetSymbolicExpressionTreeValues(model.SymbolicExpressionTree, dataset, rows);
+      var targetValues = dataset.GetDoubleValues(targetVariable, rows);
+      double alpha;
+      double beta;
+      OnlineCalculatorError errorState;
+      OnlineLinearScalingParameterCalculator.Calculate(estimatedValues, targetValues, out alpha, out beta, out errorState);
+      if (errorState != OnlineCalculatorError.None) return;
+
+      ConstantTreeNode alphaTreeNode = null;
+      ConstantTreeNode betaTreeNode = null;
+      // check if model has been scaled previously by analyzing the structure of the tree
+      var startNode = model.SymbolicExpressionTree.Root.GetSubtree(0);
+      if (startNode.GetSubtree(0).Symbol is Addition) {
+        var addNode = startNode.GetSubtree(0);
+        if (addNode.SubtreeCount == 2 && addNode.GetSubtree(0).Symbol is Multiplication && addNode.GetSubtree(1).Symbol is Constant) {
+          alphaTreeNode = addNode.GetSubtree(1) as ConstantTreeNode;
+          var mulNode = addNode.GetSubtree(0);
+          if (mulNode.SubtreeCount == 2 && mulNode.GetSubtree(1).Symbol is Constant) {
+            betaTreeNode = mulNode.GetSubtree(1) as ConstantTreeNode;
+          }
+        }
+      }
+      // if tree structure matches the structure necessary for linear scaling then reuse the existing tree nodes
+      if (alphaTreeNode != null && betaTreeNode != null) {
+        betaTreeNode.Value *= beta;
+        alphaTreeNode.Value *= beta;
+        alphaTreeNode.Value += alpha;
+      } else {
+        var mainBranch = startNode.GetSubtree(0);
+        startNode.RemoveSubtree(0);
+        var scaledMainBranch = MakeSum(MakeProduct(mainBranch, beta), alpha);
+        startNode.AddSubtree(scaledMainBranch);
+      }
+    }
+
+    private static ISymbolicExpressionTreeNode MakeSum(ISymbolicExpressionTreeNode treeNode, double alpha) {
+      if (alpha.IsAlmost(0.0)) {
+        return treeNode;
+      } else {
+        var addition = new Addition();
+        var node = addition.CreateTreeNode();
+        var alphaConst = MakeConstant(alpha);
+        node.AddSubtree(treeNode);
+        node.AddSubtree(alphaConst);
+        return node;
+      }
+    }
+
+    private static ISymbolicExpressionTreeNode MakeProduct(ISymbolicExpressionTreeNode treeNode, double beta) {
+      if (beta.IsAlmost(1.0)) {
+        return treeNode;
+      } else {
+        var multipliciation = new Multiplication();
+        var node = multipliciation.CreateTreeNode();
+        var betaConst = MakeConstant(beta);
+        node.AddSubtree(treeNode);
+        node.AddSubtree(betaConst);
+        return node;
+      }
+    }
+
+    private static ISymbolicExpressionTreeNode MakeConstant(double c) {
+      var node = (ConstantTreeNode)(new Constant()).CreateTreeNode();
+      node.Value = c;
+      return node;
+    }
+  }
+}
Index: /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/SymbolicRegressionSolution.cs
===================================================================
--- /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/SymbolicRegressionSolution.cs	(revision 7748)
+++ /branches/ProblemInstancesRegressionAndClassification/HeuristicLab.Problems.DataAnalysis.Symbolic.Regression/3.4/SymbolicRegressionSolution.cs	(revision 7748)
@@ -0,0 +1,77 @@
+#region License Information
+/* HeuristicLab
+ * Copyright (C) 2002-2012 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 HeuristicLab.Common;
+using HeuristicLab.Core;
+using HeuristicLab.Data;
+using HeuristicLab.Optimization;
+using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
+
+namespace HeuristicLab.Problems.DataAnalysis.Symbolic.Regression {
+  /// <summary>
+  /// Represents a symbolic regression solution (model + data) and attributes of the solution like accuracy and complexity
+  /// </summary>
+  [StorableClass]
+  [Item(Name = "SymbolicRegressionSolution", Description = "Represents a symbolic regression solution (model + data) and attributes of the solution like accuracy and complexity.")]
+  public sealed class SymbolicRegressionSolution : RegressionSolution, ISymbolicRegressionSolution {
+    private const string ModelLengthResultName = "Model Length";
+    private const string ModelDepthResultName = "Model Depth";
+
+    public new ISymbolicRegressionModel Model {
+      get { return (ISymbolicRegressionModel)base.Model; }
+      set { base.Model = value; }
+    }
+    ISymbolicDataAnalysisModel ISymbolicDataAnalysisSolution.Model {
+      get { return (ISymbolicDataAnalysisModel)base.Model; }
+    }
+    public int ModelLength {
+      get { return ((IntValue)this[ModelLengthResultName].Value).Value; }
+      private set { ((IntValue)this[ModelLengthResultName].Value).Value = value; }
+    }
+
+    public int ModelDepth {
+      get { return ((IntValue)this[ModelDepthResultName].Value).Value; }
+      private set { ((IntValue)this[ModelDepthResultName].Value).Value = value; }
+    }
+
+    [StorableConstructor]
+    private SymbolicRegressionSolution(bool deserializing) : base(deserializing) { }
+    private SymbolicRegressionSolution(SymbolicRegressionSolution original, Cloner cloner)
+      : base(original, cloner) {
+    }
+    public SymbolicRegressionSolution(ISymbolicRegressionModel model, IRegressionProblemData problemData)
+      : base(model, problemData) {
+      Add(new Result(ModelLengthResultName, "Length of the symbolic regression model.", new IntValue()));
+      Add(new Result(ModelDepthResultName, "Depth of the symbolic regression model.", new IntValue()));
+      RecalculateResults();
+    }
+
+    public override IDeepCloneable Clone(Cloner cloner) {
+      return new SymbolicRegressionSolution(this, cloner);
+    }
+
+    protected override void RecalculateResults() {
+      base.RecalculateResults();
+      ModelLength = Model.SymbolicExpressionTree.Length;
+      ModelDepth = Model.SymbolicExpressionTree.Depth;
+    }
+  }
+}
