source: branches/3040_VectorBasedGP/HeuristicLab.Encodings.SymbolicExpressionTreeEncoding/3.4/Manipulators/MultiSymbolicExpressionTreeManipulator.cs

#region License Information
/* HeuristicLab
 * Copyright (C) Heuristic and Evolutionary Algorithms Laboratory (HEAL)
 *
 * This file is part of HeuristicLab.
 *
 * HeuristicLab is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * HeuristicLab is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with HeuristicLab. If not, see <http://www.gnu.org/licenses/>.
 */
#endregion

using System;
using System.Collections.Generic;
using System.Linq;
using HeuristicLab.Collections;
using HeuristicLab.Common;
using HeuristicLab.Core;
using HeuristicLab.Data;
using HeuristicLab.Operators;
using HeuristicLab.Optimization;
using HeuristicLab.Parameters;
using HEAL.Attic;
using HeuristicLab.PluginInfrastructure;

namespace HeuristicLab.Encodings.SymbolicExpressionTreeEncoding {
  [Item("MultiSymbolicExpressionTreeManipulator", "Randomly selects and applies one of its manipulators every time it is called.")]
  [StorableType("0A0ED8D8-69D4-4F58-A4FD-6D97F27B4009")]
  public sealed class MultiSymbolicExpressionTreeManipulator : StochasticMultiBranch<ISymbolicExpressionTreeManipulator>,
    ISymbolicExpressionTreeManipulator,
    IStochasticOperator,
    ISymbolicExpressionTreeSizeConstraintOperator {
    private const string SymbolicExpressionTreeParameterName = "SymbolicExpressionTree";
    private const string MaximumSymbolicExpressionTreeLengthParameterName = "MaximumSymbolicExpressionTreeLength";
    private const string MaximumSymbolicExpressionTreeDepthParameterName = "MaximumSymbolicExpressionTreeDepth";

    public override bool CanChangeName {
      get { return false; }
    }
    protected override bool CreateChildOperation {
      get { return true; }
    }

    #region Parameter Properties
    public IValueLookupParameter<IntValue> MaximumSymbolicExpressionTreeLengthParameter {
      get { return (IValueLookupParameter<IntValue>)Parameters[MaximumSymbolicExpressionTreeLengthParameterName]; }
    }
    public IValueLookupParameter<IntValue> MaximumSymbolicExpressionTreeDepthParameter {
      get { return (IValueLookupParameter<IntValue>)Parameters[MaximumSymbolicExpressionTreeDepthParameterName]; }
    }
    public ILookupParameter<ISymbolicExpressionTree> SymbolicExpressionTreeParameter {
      get { return (ILookupParameter<ISymbolicExpressionTree>)Parameters[SymbolicExpressionTreeParameterName]; }
    }
    #endregion

    [StorableConstructor]
    private MultiSymbolicExpressionTreeManipulator(StorableConstructorFlag _) : base(_) { }
    private MultiSymbolicExpressionTreeManipulator(MultiSymbolicExpressionTreeManipulator original, Cloner cloner) : base(original, cloner) { }
    public MultiSymbolicExpressionTreeManipulator()
      : base() {
      Parameters.Add(new LookupParameter<ISymbolicExpressionTree>(SymbolicExpressionTreeParameterName, "The symbolic expression tree on which the operator should be applied."));
      Parameters.Add(new ValueLookupParameter<IntValue>(MaximumSymbolicExpressionTreeLengthParameterName, "The maximal length (number of nodes) of the symbolic expression tree."));
      Parameters.Add(new ValueLookupParameter<IntValue>(MaximumSymbolicExpressionTreeDepthParameterName, "The maximal depth of the symbolic expression tree (a tree with one node has depth = 0)."));

      List<ISymbolicExpressionTreeManipulator> list = new List<ISymbolicExpressionTreeManipulator>();
      foreach (Type type in ApplicationManager.Manager.GetTypes(typeof(ISymbolicExpressionTreeManipulator))) {
        if (this.GetType().Assembly != type.Assembly) continue;
        if (typeof(IMultiOperator<ISymbolicExpressionTreeManipulator>).IsAssignableFrom(type)) continue;
        if (typeof(ISymbolicExpressionTreeArchitectureAlteringOperator).IsAssignableFrom(type)) continue;
        list.Add((ISymbolicExpressionTreeManipulator)Activator.CreateInstance(type));
      }
      CheckedItemList<ISymbolicExpressionTreeManipulator> checkedItemList = new CheckedItemList<ISymbolicExpressionTreeManipulator>();
      checkedItemList.AddRange(list.OrderBy(op => op.Name));
      //Operators = checkedItemList.AsReadOnly();
      Operators = checkedItemList;
      Operators_ItemsAdded(this, new CollectionItemsChangedEventArgs<IndexedItem<ISymbolicExpressionTreeManipulator>>(Operators.CheckedItems));

      SelectedOperatorParameter.ActualName = "SelectedManipulationOperator";
    }

    public override IDeepCloneable Clone(Cloner cloner) {
      return new MultiSymbolicExpressionTreeManipulator(this, cloner);
    }

    public void Manipulate(IRandom random, ISymbolicExpressionTree symbolicExpressionTree) {
      double sum = Operators.CheckedItems.Sum(o => Probabilities[o.Index]);
      if (sum.IsAlmost(0)) throw new InvalidOperationException(Name + ": All selected operators have zero probability.");
      double r = random.NextDouble() * sum;
      sum = 0;
      int index = -1;
      foreach (var indexedItem in Operators.CheckedItems) {
        sum += Probabilities[indexedItem.Index];
        if (sum > r) {
          index = indexedItem.Index;
          break;
        }
      }
      Operators[index].Manipulate(random, symbolicExpressionTree);
    }

    protected override void Operators_ItemsReplaced(object sender, CollectionItemsChangedEventArgs<IndexedItem<ISymbolicExpressionTreeManipulator>> e) {
      base.Operators_ItemsReplaced(sender, e);
      ParameterizeManipulators();
    }

    protected override void Operators_ItemsAdded(object sender, CollectionItemsChangedEventArgs<IndexedItem<ISymbolicExpressionTreeManipulator>> e) {
      base.Operators_ItemsAdded(sender, e);
      ParameterizeManipulators();
    }

    private void ParameterizeManipulators() {
      foreach (IStochasticOperator manipulator in Operators.OfType<IStochasticOperator>()) {
        manipulator.RandomParameter.ActualName = RandomParameter.Name;
      }
      foreach (ISymbolicExpressionTreeManipulator manipulator in Operators.OfType<ISymbolicExpressionTreeManipulator>()) {
        manipulator.SymbolicExpressionTreeParameter.ActualName = SymbolicExpressionTreeParameter.Name;
      }
      foreach (ISymbolicExpressionTreeSizeConstraintOperator manipulator in Operators.OfType<ISymbolicExpressionTreeSizeConstraintOperator>()) {
        manipulator.MaximumSymbolicExpressionTreeDepthParameter.ActualName = MaximumSymbolicExpressionTreeDepthParameter.Name;
        manipulator.MaximumSymbolicExpressionTreeLengthParameter.ActualName = MaximumSymbolicExpressionTreeLengthParameter.Name;
      }
    }
  }
}