Index: /trunk/sources/HeuristicLab.Problems.DataAnalysis.Regression/3.3/Symbolic/Symbols/Constant.cs
===================================================================
--- /trunk/sources/HeuristicLab.Problems.DataAnalysis.Regression/3.3/Symbolic/Symbols/Constant.cs	(revision 3258)
+++ /trunk/sources/HeuristicLab.Problems.DataAnalysis.Regression/3.3/Symbolic/Symbols/Constant.cs	(revision 3258)
@@ -0,0 +1,29 @@
+#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 HeuristicLab.Encodings.SymbolicExpressionTreeEncoding;
+namespace HeuristicLab.Problems.DataAnalysis.Regression.Symbolic.Symbols {
+  public sealed class Constant : Symbol {
+    public override SymbolicExpressionTreeNode CreateTreeNode() {
+      return new ConstantTreeNode(this);
+    }
+  }
+}
Index: /trunk/sources/HeuristicLab.Problems.DataAnalysis.Regression/3.3/Symbolic/Symbols/ConstantTreeNode.cs
===================================================================
--- /trunk/sources/HeuristicLab.Problems.DataAnalysis.Regression/3.3/Symbolic/Symbols/ConstantTreeNode.cs	(revision 3258)
+++ /trunk/sources/HeuristicLab.Problems.DataAnalysis.Regression/3.3/Symbolic/Symbols/ConstantTreeNode.cs	(revision 3258)
@@ -0,0 +1,54 @@
+#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 HeuristicLab.Encodings.SymbolicExpressionTreeEncoding;
+using System;
+using System.Collections.Generic;
+using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
+namespace HeuristicLab.Problems.DataAnalysis.Regression.Symbolic.Symbols {
+  [StorableClass]
+  public sealed class ConstantTreeNode : SymbolicExpressionTreeTerminalNode {
+    public override bool HasLocalParameters {
+      get {
+        return true;
+      }
+    }
+
+    private double constantValue;
+    [Storable]
+    public double Value {
+      get { return constantValue; }
+      set { constantValue = value; }
+    }
+
+    // copy constructor
+    private ConstantTreeNode(ConstantTreeNode original)
+      : base(original) {
+      constantValue = original.constantValue;
+    }
+
+    public ConstantTreeNode(Constant constantSymbol) : base(constantSymbol) { }
+
+    public override object Clone() {
+      return new ConstantTreeNode(this);
+    }
+  }
+}
Index: /trunk/sources/HeuristicLab.Problems.DataAnalysis.Regression/3.3/Symbolic/Symbols/Variable.cs
===================================================================
--- /trunk/sources/HeuristicLab.Problems.DataAnalysis.Regression/3.3/Symbolic/Symbols/Variable.cs	(revision 3258)
+++ /trunk/sources/HeuristicLab.Problems.DataAnalysis.Regression/3.3/Symbolic/Symbols/Variable.cs	(revision 3258)
@@ -0,0 +1,29 @@
+#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 HeuristicLab.Encodings.SymbolicExpressionTreeEncoding;
+namespace HeuristicLab.Problems.DataAnalysis.Regression.Symbolic.Symbols {
+  public sealed class Variable : Symbol {
+    public override SymbolicExpressionTreeNode CreateTreeNode() {
+      return new VariableTreeNode(this);
+    }
+  }
+}
Index: /trunk/sources/HeuristicLab.Problems.DataAnalysis.Regression/3.3/Symbolic/Symbols/VariableTreeNode.cs
===================================================================
--- /trunk/sources/HeuristicLab.Problems.DataAnalysis.Regression/3.3/Symbolic/Symbols/VariableTreeNode.cs	(revision 3258)
+++ /trunk/sources/HeuristicLab.Problems.DataAnalysis.Regression/3.3/Symbolic/Symbols/VariableTreeNode.cs	(revision 3258)
@@ -0,0 +1,56 @@
+#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 HeuristicLab.Encodings.SymbolicExpressionTreeEncoding;
+using System;
+using System.Collections.Generic;
+using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
+namespace HeuristicLab.Problems.DataAnalysis.Regression.Symbolic.Symbols {
+  [StorableClass]
+  public sealed class VariableTreeNode : SymbolicExpressionTreeTerminalNode {
+    
+    private double weight;
+    [Storable]
+    public double Weight {
+      get { return weight; }
+      set { weight = value; }
+    }
+    private string variableName;
+    [Storable]
+    public string VariableName {
+      get { return variableName; }
+      set { variableName = value; }
+    }
+
+    // copy constructor
+    private VariableTreeNode(VariableTreeNode original)
+      : base(original) {
+      weight = original.weight;
+      variableName = original.variableName;
+    }
+
+    public VariableTreeNode(Variable variableSymbol) : base(variableSymbol) { }
+
+    public override object Clone() {
+      return new VariableTreeNode(this);
+    }
+  }
+}
