Changeset 3817 for trunk/sources/HeuristicLab.Operators

Timestamp:

05/16/10 23:31:08 (15 years ago)

Author:

swagner

Message:

Implemented reviewers' comments (#893)

Location:

trunk/sources/HeuristicLab.Operators/3.3

Files:

• HeuristicLab.Operators-3.3.csproj (modified) (1 diff)
• StochasticMultiBranch.cs (modified) (1 diff)
• StochasticMultiBranchOfT.cs (deleted)

trunk/sources/HeuristicLab.Operators/3.3/HeuristicLab.Operators-3.3.csproj ¶

@@ -92 +92 @@
     <Compile Include="Assigner.cs" />
     <Compile Include="AlgorithmOperator.cs" />
-    <Compile Include="StochasticMultiBranchOfT.cs" />
     <Compile Include="MultiOperator.cs" />
     <Compile Include="Operator.cs" />

trunk/sources/HeuristicLab.Operators/3.3/StochasticMultiBranch.cs ¶

@@ -34 +34 @@
   /// Selects one of its branches (if there are any) given a list of relative probabilities.
   /// </summary>
+  [Item("StochasticMultiBranch<T>", "Selects one of its branches (if there are any) given a list of relative probabilities.")]
+  [StorableClass]
+  public abstract class StochasticMultiBranch<T> : CheckedMultiOperator<T> where T : class, IOperator {
+    /// <summary>
+    /// Should return true if the StochasticMultiOperator should create a new child operation with the selected successor
+    /// or if it should create a new operation. If you need to shield the parameters of the successor you should return true here.
+    /// </summary>
+    protected abstract bool CreateChildOperation { get; }
+
+    public ValueLookupParameter<DoubleArray> ProbabilitiesParameter {
+      get { return (ValueLookupParameter<DoubleArray>)Parameters["Probabilities"]; }
+    }
+    public ILookupParameter<IRandom> RandomParameter {
+      get { return (ILookupParameter<IRandom>)Parameters["Random"]; }
+    }
+
+    public DoubleArray Probabilities {
+      get { return ProbabilitiesParameter.Value; }
+      set { ProbabilitiesParameter.Value = value; }
+    }
+
+    [StorableConstructor]
+    protected StochasticMultiBranch(bool deserializing) : base(deserializing) { }
+    /// <summary>
+    /// Initializes a new instance of <see cref="StochasticMultiOperator"/> with two parameters
+    /// (<c>Probabilities</c> and <c>Random</c>).
+    /// </summary>
+    public StochasticMultiBranch()
+      : base() {
+      Parameters.Add(new ValueLookupParameter<DoubleArray>("Probabilities", "The array of relative probabilities for each operator.", new DoubleArray()));
+      Parameters.Add(new LookupParameter<IRandom>("Random", "The random number generator to use."));
+    }
+
+    protected override void Operators_ItemsRemoved(object sender, CollectionItemsChangedEventArgs<IndexedItem<T>> e) {
+      base.Operators_ItemsRemoved(sender, e);
+      if (Probabilities != null && Probabilities.Length > Operators.Count) {
+        List<double> probs = new List<double>(Probabilities.Cast<double>());
+        var sorted = e.Items.OrderByDescending(x => x.Index);
+        foreach (IndexedItem<T> item in sorted)
+          if (probs.Count > item.Index) probs.RemoveAt(item.Index);
+        Probabilities = new DoubleArray(probs.ToArray());
+      }
+    }
+
+    protected override void Operators_ItemsAdded(object sender, HeuristicLab.Collections.CollectionItemsChangedEventArgs<IndexedItem<T>> e) {
+      base.Operators_ItemsAdded(sender, e);
+      if (Probabilities != null && Probabilities.Length < Operators.Count) {
+        double avg = (Probabilities.Where(x => x > 0).Count() > 0) ? (Probabilities.Where(x => x > 0).Average()) : (1);
+        // add the average of all probabilities in the respective places (the new operators)
+        var added = e.Items.OrderBy(x => x.Index).ToList();
+        int insertCount = 0;
+        DoubleArray probs = new DoubleArray(Operators.Count);
+        for (int i = 0; i < Operators.Count; i++) {
+          if (insertCount < added.Count && i == added[insertCount].Index) {
+            probs[i] = avg;
+            insertCount++;
+          } else if (i - insertCount < Probabilities.Length) {
+            probs[i] = Probabilities[i - insertCount];
+          } else probs[i] = avg;
+        }
+        Probabilities = probs;
+      }
+    }
+
+    /// <summary>
+    /// Applies an operator of the branches to the current scope with a 
+    /// specific probability.
+    /// </summary>
+    /// <exception cref="InvalidOperationException">Thrown when the list of probabilites does not
+    /// match the number of operators, the list of selected operators is empty, 
+    /// or all selected operators have zero probabitlity.</exception>
+    /// <returns>A new operation with the operator that was selected followed by the current operator's successor.</returns>
+    public override IOperation Apply() {
+      IRandom random = RandomParameter.ActualValue;
+      DoubleArray probabilities = ProbabilitiesParameter.ActualValue;
+      if (probabilities.Length != Operators.Count) {
+        throw new InvalidOperationException(Name + ": The list of probabilities has to match the number of operators");
+      }
+      IOperator successor = null;
+      var checkedOperators = Operators.CheckedItems;
+      if (checkedOperators.Count() > 0) {
+        // select a random operator from the checked operators
+        double sum = (from indexedItem in checkedOperators select probabilities[indexedItem.Index]).Sum();
+        if (sum == 0) throw new InvalidOperationException(Name + ": All selected operators have zero probability.");
+        double r = random.NextDouble() * sum;
+        sum = 0;
+        foreach (var indexedItem in checkedOperators) {
+          sum += probabilities[indexedItem.Index];
+          if (sum > r) {
+            successor = indexedItem.Value;
+            break;
+          }
+        }
+      }
+      OperationCollection next = new OperationCollection(base.Apply());
+      if (successor != null) {
+        if (CreateChildOperation)
+          next.Insert(0, ExecutionContext.CreateChildOperation(successor));
+        else next.Insert(0, ExecutionContext.CreateOperation(successor));
+      }
+      return next;
+    }
+  }
+
+  /// <summary>
+  /// Selects one of its branches (if there are any) given a list of relative probabilities.
+  /// </summary>
   [Item("StochasticMultiBranch", "Selects one of its branches (if there are any) given a list of relative probabilities.")]
   [StorableClass]