Changeset 7076 for trunk/sources/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding/3.4/Creators/GrowTreeCreator.cs

Timestamp:

11/25/11 15:25:54 (13 years ago)

Author:

mkommend

Message:

#1654: Corrected tree creators for symbolic expression encoding.

File:

• trunk/sources/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding/3.4/Creators/GrowTreeCreator.cs (modified) (2 diffs)

trunk/sources/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding/3.4/Creators/GrowTreeCreator.cs

@@ -64 +64 @@
     }
 
-    public IntValue MaximumSymbolicExpressionTreeLength { 
+    public IntValue MaximumSymbolicExpressionTreeLength {
       get { return MaximumSymbolicExpressionTreeLengthParameter.ActualValue; }
     }
@@ -166 +166 @@
         throw new ArgumentException("Cannot grow node of arity zero. Expected a function node.");
 
-
       for (var i = 0; i != arity; ++i) {
-        var possibleSymbols = currentDepth < maxDepth
-                                ? root.Grammar.GetAllowedChildSymbols(root.Symbol,i).Where(s => s.InitialFrequency > 0.0)
-                                : root.Grammar.GetAllowedChildSymbols(root.Symbol,i).Where(
-                                  s => s.InitialFrequency > 0.0 && root.Grammar.GetMaximumSubtreeCount(s) == 0);
+        var possibleSymbols = root.Grammar.GetAllowedChildSymbols(root.Symbol, i);
+        possibleSymbols = possibleSymbols.Where(s => s.InitialFrequency > 0.0 &&
+                                          root.Grammar.GetMinimumExpressionDepth(s) - 1 <= maxDepth - currentDepth);
+        if (!possibleSymbols.Any()) throw new InvalidOperationException("No symbols are available for the tree.");
         var selectedSymbol = possibleSymbols.SelectRandom(random);
         var tree = selectedSymbol.CreateTreeNode();