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Ignore:
Timestamp:
05/03/10 17:42:24 (15 years ago)
Author:
abeham
Message:

Made StochasticMultiBranch<T> abstract and added non-generic type StochasticMultiBranch #997

Location:
trunk/sources/HeuristicLab.Operators/3.3
Files:
1 added
2 edited

Legend:

Unmodified
Added
Removed

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

    r3593 r3597  
    9292    <Compile Include="Assigner.cs" />
    9393    <Compile Include="AlgorithmOperator.cs" />
     94    <Compile Include="StochasticMultiBranchOfT.cs" />
    9495    <Compile Include="MultiOperator.cs" />
    9596    <Compile Include="Operator.cs" />

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

    r3593 r3597  
    3434  /// Selects one of its branches (if there are any) given a list of relative probabilities.
    3535  /// </summary>
    36   [Item("StochasticMultiBranch<T>", "Selects one of its branches (if there are any) given a list of relative probabilities.")]
     36  [Item("StochasticMultiBranch", "Selects one of its branches (if there are any) given a list of relative probabilities.")]
    3737  [StorableClass]
    38   public class StochasticMultiBranch<T> : CheckedMultiOperator<T> where T : class, IOperator {
    39     /// <summary>
    40     /// Should return true if the StochasticMultiOperator should create a new child operation with the selected successor
    41     /// or if it should create a new operation. If you need to shield the parameters of the successor you should return true here.
    42     /// </summary>
    43     protected virtual bool CreateChildOperation {
     38  public class StochasticMultiBranch : StochasticMultiBranch<IOperator> {
     39    protected override bool CreateChildOperation {
    4440      get { return false; }
    45     }
    46 
    47     public ValueLookupParameter<DoubleArray> ProbabilitiesParameter {
    48       get { return (ValueLookupParameter<DoubleArray>)Parameters["Probabilities"]; }
    49     }
    50     public ILookupParameter<IRandom> RandomParameter {
    51       get { return (ILookupParameter<IRandom>)Parameters["Random"]; }
    52     }
    53 
    54     public DoubleArray Probabilities {
    55       get { return ProbabilitiesParameter.Value; }
    56       set { ProbabilitiesParameter.Value = value; }
    57     }
    58 
    59     [StorableConstructor]
    60     protected StochasticMultiBranch(bool deserializing) : base(deserializing) { }
    61     /// <summary>
    62     /// Initializes a new instance of <see cref="StochasticMultiOperator"/> with two parameters
    63     /// (<c>Probabilities</c> and <c>Random</c>).
    64     /// </summary>
    65     public StochasticMultiBranch()
    66       : base() {
    67       Parameters.Add(new ValueLookupParameter<DoubleArray>("Probabilities", "The array of relative probabilities for each operator.", new DoubleArray()));
    68       Parameters.Add(new LookupParameter<IRandom>("Random", "The random number generator to use."));
    69     }
    70 
    71     protected override void Operators_ItemsRemoved(object sender, CollectionItemsChangedEventArgs<IndexedItem<T>> e) {
    72       base.Operators_ItemsRemoved(sender, e);
    73       if (Probabilities != null && Probabilities.Length > Operators.Count) {
    74         List<double> probs = new List<double>(Probabilities.Cast<double>());
    75         var sorted = e.Items.OrderByDescending(x => x.Index);
    76         foreach (IndexedItem<T> item in sorted)
    77           if (probs.Count > item.Index) probs.RemoveAt(item.Index);
    78         Probabilities = new DoubleArray(probs.ToArray());
    79       }
    80     }
    81 
    82     protected override void Operators_ItemsAdded(object sender, HeuristicLab.Collections.CollectionItemsChangedEventArgs<IndexedItem<T>> e) {
    83       base.Operators_ItemsAdded(sender, e);
    84       if (Probabilities != null && Probabilities.Length < Operators.Count) {
    85         double avg = (Probabilities.Where(x => x > 0).Count() > 0) ? (Probabilities.Where(x => x > 0).Average()) : (1);
    86         // add the average of all probabilities in the respective places (the new operators)
    87         var added = e.Items.OrderBy(x => x.Index).ToList();
    88         int insertCount = 0;
    89         DoubleArray probs = new DoubleArray(Operators.Count);
    90         for (int i = 0; i < Operators.Count; i++) {
    91           if (insertCount < added.Count && i == added[insertCount].Index) {
    92             probs[i] = avg;
    93             insertCount++;
    94           } else if (i - insertCount < Probabilities.Length) {
    95             probs[i] = Probabilities[i - insertCount];
    96           } else probs[i] = avg;
    97         }
    98         Probabilities = probs;
    99       }
    100     }
    101 
    102     /// <summary>
    103     /// Applies an operator of the branches to the current scope with a
    104     /// specific probability.
    105     /// </summary>
    106     /// <exception cref="InvalidOperationException">Thrown when the list of probabilites does not
    107     /// match the number of operators, the list of selected operators is empty,
    108     /// or all selected operators have zero probabitlity.</exception>
    109     /// <returns>A new operation with the operator that was selected followed by the current operator's successor.</returns>
    110     public override IOperation Apply() {
    111       IRandom random = RandomParameter.ActualValue;
    112       DoubleArray probabilities = ProbabilitiesParameter.ActualValue;
    113       if (probabilities.Length != Operators.Count) {
    114         throw new InvalidOperationException(Name + ": The list of probabilities has to match the number of operators");
    115       }
    116       IOperator successor = null;
    117       var checkedOperators = Operators.CheckedItems;
    118       if (checkedOperators.Count() > 0) {
    119         // select a random operator from the checked operators
    120         double sum = (from indexedItem in checkedOperators select probabilities[indexedItem.Index]).Sum();
    121         if (sum == 0) throw new InvalidOperationException(Name + ": All selected operators have zero probability.");
    122         double r = random.NextDouble() * sum;
    123         sum = 0;
    124         foreach (var indexedItem in checkedOperators) {
    125           sum += probabilities[indexedItem.Index];
    126           if (sum > r) {
    127             successor = indexedItem.Value;
    128             break;
    129           }
    130         }
    131       }
    132       OperationCollection next = new OperationCollection(base.Apply());
    133       if (successor != null) {
    134         if (CreateChildOperation)
    135           next.Insert(0, ExecutionContext.CreateChildOperation(successor));
    136         else next.Insert(0, ExecutionContext.CreateOperation(successor));
    137       }
    138       return next;
    13941    }
    14042  }
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