Changeset 5499 for branches/DataAnalysis Refactoring/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding/3.4/Manipulators/ChangeNodeTypeManipulation.cs

Timestamp:

02/16/11 19:01:00 (13 years ago)

Author:

gkronber

Message:

#1418 changes in symbolic expression tree encoding.

Location:

branches/DataAnalysis Refactoring/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding/3.4

Files:

• . (modified) (1 prop)
• Manipulators/ChangeNodeTypeManipulation.cs (modified) (3 diffs)

branches/DataAnalysis Refactoring/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding/3.4

@@ -2 +2 @@
 obj
 HeuristicLabEncodingsSymbolicExpressionTreeEncodingPlugin.cs
+*.user

@@ -2 +2 @@
 obj
 HeuristicLabEncodingsSymbolicExpressionTreeEncodingPlugin.cs
+*.user

branches/DataAnalysis Refactoring/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding/3.4/Manipulators/ChangeNodeTypeManipulation.cs

@@ -26 +26 @@
 using HeuristicLab.Core;
 using HeuristicLab.Data;
-using HeuristicLab.Encodings.SymbolicExpressionTreeEncoding.Symbols;
 using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
 
-namespace HeuristicLab.Encodings.SymbolicExpressionTreeEncoding.Manipulators {
+namespace HeuristicLab.Encodings.SymbolicExpressionTreeEncoding {
   [StorableClass]
   [Item("ChangeNodeTypeManipulation", "Selects a random tree node and changes the symbol.")]
   public sealed class ChangeNodeTypeManipulation : SymbolicExpressionTreeManipulator {
-
     [StorableConstructor]
     private ChangeNodeTypeManipulation(bool deserializing) : base(deserializing) { }
@@ -43 +41 @@
     }
 
-    protected override void Manipulate(IRandom random, SymbolicExpressionTree symbolicExpressionTree, ISymbolicExpressionGrammar grammar, IntValue maxTreeSize, IntValue maxTreeHeight, out bool success) {
-      ChangeNodeType(random, symbolicExpressionTree, grammar, maxTreeSize.Value, maxTreeHeight.Value, out success);
+    protected override void Manipulate(IRandom random, SymbolicExpressionTree symbolicExpressionTree) {
+      ChangeNodeType(random, symbolicExpressionTree);
     }
 
-    public static void ChangeNodeType(IRandom random, SymbolicExpressionTree symbolicExpressionTree, ISymbolicExpressionGrammar grammar, int maxTreeSize, int maxTreeHeight, out bool success) {
+    public static void ChangeNodeType(IRandom random, SymbolicExpressionTree symbolicExpressionTree) {
 
       // select any node as parent (except the root node)
       var manipulationPoint = (from parent in symbolicExpressionTree.Root.IterateNodesPrefix().Skip(1)
                                from subtree in parent.SubTrees
-                               select new { Parent = parent, Node = subtree, Index = parent.SubTrees.IndexOf(subtree) }).SelectRandom(random);
+                               select new { Parent = parent, Node = subtree, Index = parent.IndexOfSubTree(subtree) })
+                               .SelectRandom(random);
+      int subTreeCount = manipulationPoint.Node.SubTrees.Count();
       // find possible symbols for the node (also considering the existing branches below it)
       var allowedSymbols = from symbol in manipulationPoint.Parent.GetAllowedSymbols(manipulationPoint.Index)
-                           where manipulationPoint.Node.SubTrees.Count <= manipulationPoint.Node.Grammar.GetMaxSubtreeCount(symbol)
-                           where manipulationPoint.Node.SubTrees.Count >= manipulationPoint.Node.Grammar.GetMinSubtreeCount(symbol)
+                           where subTreeCount <= manipulationPoint.Node.Grammar.GetMaxSubtreeCount(symbol)
+                           where subTreeCount >= manipulationPoint.Node.Grammar.GetMinSubtreeCount(symbol)
                            select symbol;
 
       if (allowedSymbols.Count() == 0) {
-        success = false;
         return;
       }
       var node = manipulationPoint.Node;
       // keep only symbols that are still possible considering the existing sub-trees
-      var constrainedSymbols = from symbol in allowedSymbols
-                               let disallowedSubtrees =
-                                     from subtree in node.SubTrees
-                                     where !node.Grammar.IsAllowedChild(symbol, subtree.Symbol, node.SubTrees.IndexOf(subtree))
-                                     select subtree
-                               where disallowedSubtrees.Count() == 0
-                               select symbol;
+      var constrainedSymbols = (from symbol in allowedSymbols
+                                let disallowedSubtrees =
+                                      from subtree in node.SubTrees
+                                      where !node.Grammar.IsAllowedChild(symbol, subtree.Symbol, node.IndexOfSubTree(subtree))
+                                      select subtree
+                                where disallowedSubtrees.Count() == 0
+                                select symbol)
+                               .ToList();
       if (constrainedSymbols.Count() == 0) {
-        success = false;
         return;
       }
-      var newSymbol = SelectRandomSymbol(random, constrainedSymbols);
+      var weights = constrainedSymbols.Select(s => s.InitialFrequency).ToList();
+      var newSymbol =  constrainedSymbols.SelectRandom(weights, random);
 
       // replace the old node with the new node
@@ -86 +86 @@
       manipulationPoint.Parent.RemoveSubTree(manipulationPoint.Index);
       manipulationPoint.Parent.InsertSubTree(manipulationPoint.Index, newNode);
-      success = true;
-    }
-
-    private static Symbol SelectRandomSymbol(IRandom random, IEnumerable<Symbol> symbols) {
-      var symbolList = symbols.ToList();
-      var ticketsSum = symbolList.Select(x => x.InitialFrequency).Sum();
-      if (ticketsSum == 0.0) throw new ArgumentException("The initial frequency of all allowed symbols is zero.");
-      var r = random.NextDouble() * ticketsSum;
-      double aggregatedTickets = 0;
-      for (int i = 0; i < symbolList.Count; i++) {
-        aggregatedTickets += symbolList[i].InitialFrequency;
-        if (aggregatedTickets > r) {
-          return symbolList[i];
-        }
-      }
-      // this should never happen
-      throw new ArgumentException("There is a problem with the initial frequency setting of allowed symbols.");
     }
   }

@@ -2 +2 @@
 obj
 HeuristicLabEncodingsSymbolicExpressionTreeEncodingPlugin.cs
+*.user