Changeset 1286 for trunk/sources/HeuristicLab.GP/Recombination/GPCrossoverBase.cs

Timestamp:

03/08/09 11:04:49 (15 years ago)

Author:

gkronber

Message:

Adapted GP crossover operators to match the new design for crossover operators. #512 (GP crossover operators should be changed to match the new design of crossover operators (see #475)).

File:

• trunk/sources/HeuristicLab.GP/Recombination/GPCrossoverBase.cs (modified) (2 diffs)

trunk/sources/HeuristicLab.GP/Recombination/GPCrossoverBase.cs

@@ -30 +30 @@
 using HeuristicLab.Constraints;
 using System.Diagnostics;
+using HeuristicLab.Evolutionary;
 
 namespace HeuristicLab.GP {
-  public abstract class GPCrossoverBase : OperatorBase {
+  public abstract class GPCrossoverBase : CrossoverBase {
     public GPCrossoverBase()
       : base() {
-      AddVariableInfo(new VariableInfo("Random", "Pseudo random number generator", typeof(MersenneTwister), VariableKind.In));
       AddVariableInfo(new VariableInfo("OperatorLibrary", "The operator library containing all available operators", typeof(GPOperatorLibrary), VariableKind.In));
       AddVariableInfo(new VariableInfo("FunctionTree", "The tree to mutate", typeof(IFunctionTree), VariableKind.In | VariableKind.New));
@@ -42 +42 @@
     }
 
-    public override IOperation Apply(IScope scope) {
-      MersenneTwister random = GetVariableValue<MersenneTwister>("Random", scope, true);
+    internal abstract IFunctionTree Cross(IScope scope, TreeGardener gardener, IRandom random, IFunctionTree tree0, IFunctionTree tree1);
+
+    protected override void Cross(IScope scope, IRandom random) {
       GPOperatorLibrary opLibrary = GetVariableValue<GPOperatorLibrary>("OperatorLibrary", scope, true);
       TreeGardener gardener = new TreeGardener(random, opLibrary);
 
-      if ((scope.SubScopes.Count % 2) != 0)
-        throw new InvalidOperationException("Number of parents is not even");
+      if (scope.SubScopes.Count != 2)
+        throw new InvalidOperationException("Number of parents must be exactly two.");
 
-      int children = scope.SubScopes.Count / 2;
-      for (int i = 0; i < children; i++) {
-        IFunctionTree parent0 = TakeNextParent(scope);
-        IFunctionTree parent1 = TakeNextParent(scope);
+      IFunctionTree parent0 = GetVariableValue<IFunctionTree>("FunctionTree", scope.SubScopes[0], false);
+      IFunctionTree parent1 = GetVariableValue<IFunctionTree>("FunctionTree", scope.SubScopes[1], false);
 
-        // randomly swap parents to remove a possible bias from selection (e.g. when using gender-specific selection)
-        if (random.NextDouble() < 0.5) {
-          IFunctionTree tmp = parent0;
-          parent0 = parent1;
-          parent1 = tmp;
-        }
-
-        IFunctionTree child = Cross(scope, gardener, random, parent0, parent1);
-        Debug.Assert(gardener.IsValidTree(child));
-        IScope childScope = new Scope(i.ToString());
-        childScope.AddVariable(new HeuristicLab.Core.Variable(scope.TranslateName("FunctionTree"), child));
-        childScope.AddVariable(new HeuristicLab.Core.Variable(scope.TranslateName("TreeSize"), new IntData(child.Size)));
-        childScope.AddVariable(new HeuristicLab.Core.Variable(scope.TranslateName("TreeHeight"), new IntData(child.Height)));
-        scope.AddSubScope(childScope);
+      // randomly swap parents to remove a possible bias from selection (e.g. when using gender-specific selection)
+      if (random.NextDouble() < 0.5) {
+        IFunctionTree tmp = parent0;
+        parent0 = parent1;
+        parent1 = tmp;
       }
 
-      return null;
-    }
-
-    internal abstract IFunctionTree Cross(IScope scope, TreeGardener gardener, MersenneTwister random, IFunctionTree tree0, IFunctionTree tree1);
-
-    private IFunctionTree TakeNextParent(IScope scope) {
-      IFunctionTree parent = GetVariableValue<IFunctionTree>("FunctionTree", scope.SubScopes[0], false);
-      scope.RemoveSubScope(scope.SubScopes[0]);
-      return parent;
+      IFunctionTree child = Cross(scope, gardener, random, parent0, parent1);
+      Debug.Assert(gardener.IsValidTree(child));
+      scope.AddVariable(new HeuristicLab.Core.Variable(scope.TranslateName("FunctionTree"), child));
+      scope.AddVariable(new HeuristicLab.Core.Variable(scope.TranslateName("TreeSize"), new IntData(child.Size)));
+      scope.AddVariable(new HeuristicLab.Core.Variable(scope.TranslateName("TreeHeight"), new IntData(child.Height)));
     }
   }