Changeset 3905 for trunk/sources/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding

Timestamp:

06/08/10 17:47:15 (14 years ago)

Author:

gkronber

Message:

Implemented calculation of variable impacts as integral over relative variable frequencies. #1036

File:

• trunk/sources/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding/3.3/SymbolicExpressionTreeNode.cs (modified) (1 diff)

trunk/sources/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding/3.3/SymbolicExpressionTreeNode.cs

@@ -121 +121 @@
 
     public IEnumerable<SymbolicExpressionTreeNode> IterateNodesPrefix() {
-      return (new SymbolicExpressionTreeNode[] { this })
-        .Concat(SubTrees.SelectMany(tree => tree.IterateNodesPrefix()));
+      if (SubTrees != null) {
+        return (new SymbolicExpressionTreeNode[] { this })
+          .Concat(SubTrees.SelectMany(tree => tree.IterateNodesPrefix()));
+      } else {
+        return new SymbolicExpressionTreeNode[] { this };
+      }
     }
 
     public IEnumerable<SymbolicExpressionTreeNode> IterateNodesPostfix() {
-      return SubTrees.SelectMany(tree => tree.IterateNodesPrefix())
-        .Concat(new SymbolicExpressionTreeNode[] { this });
+      if (SubTrees != null) {
+        return SubTrees.SelectMany(tree => tree.IterateNodesPrefix())
+          .Concat(new SymbolicExpressionTreeNode[] { this });
+      } else {
+        return new SymbolicExpressionTreeNode[] { this };
+      }
     }
     public IEnumerable<Symbol> GetAllowedSymbols(int argumentIndex) {