Ticket #2320: SymbolicExpressionTreeEncoding.cs

#region License Information

/* HeuristicLab
 * Copyright (C) 2002-2015 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.Common;
using HeuristicLab.Core;
using HeuristicLab.Data;
using HeuristicLab.Optimization;
using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
using HeuristicLab.PluginInfrastructure;

namespace HeuristicLab.Encodings.SymbolicExpressionTreeEncoding {
  [Item("SymbolicExpressionTreeEncoding", "Describes a symbolic expression tree encoding.")]
  [StorableClass]
  public class SymbolicExpressionTreeEncoding : Encoding<ISymbolicExpressionTreeCreator> {
    #region Encoding Parameters
    [Storable]
    private IFixedValueParameter<IntValue> treeLengthParameter;
    public IFixedValueParameter<IntValue> TreeLengthParameter {
      get { return treeLengthParameter; }
      set {
        if (value == null) throw new ArgumentNullException("Tree length parameter must not be null.");
        if (value.Value == null) throw new ArgumentNullException("Tree length parameter value must not be null.");
        if (treeLengthParameter == value) return;

        if (treeLengthParameter != null)
          Parameters.Remove(treeLengthParameter);

        treeLengthParameter = value;
        Parameters.Add(treeLengthParameter);
      }
    }

    [Storable]
    private IFixedValueParameter<IntValue> treeDepthParameter;
    public IFixedValueParameter<IntValue> TreeDepthParameter {
      get { return treeDepthParameter; }
      set {
        if (value == null) throw new ArgumentNullException("Tree length parameter must not be null.");
        if (value.Value == null) throw new ArgumentNullException("Tree length parameter value must not be null.");
        if (treeDepthParameter == value) return;

        if (treeDepthParameter != null)
          Parameters.Remove(treeDepthParameter);

        treeDepthParameter = value;
        Parameters.Add(treeDepthParameter);
      }
    }
    #endregion


    [StorableConstructor]
    public SymbolicExpressionTreeEncoding(bool deserializing) : base(deserializing) { }

    public SymbolicExpressionTreeEncoding(Encoding<ISymbolicExpressionTreeCreator> original, Cloner cloner)
      : base(original, cloner) {
    }

    public SymbolicExpressionTreeEncoding() : this("SymbolicExpressionTree") { }
    public SymbolicExpressionTreeEncoding(string name) : base(name) { }

    private SymbolicExpressionTreeEncoding(SymbolicExpressionTreeEncoding original, Cloner cloner)
      : base(original, cloner) {
    }

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

    public override void ConfigureOperators(IEnumerable<IOperator> operators) {
      ConfigureCreators(operators.OfType<ISymbolicExpressionTreeCreator>());
      ConfigureCrossovers(operators.OfType<ISymbolicExpressionTreeCrossover>());
      ConfigureManipulators(operators.OfType<ISymbolicExpressionTreeManipulator>());
    }

    private void OnLengthParameterChanged() {
      RegisterLengthParameterEvents();
      ConfigureOperators(Operators);
    }

    private void OnDepthParameterChanged() {
      RegisterDepthParameterEvents();
      ConfigureOperators(Operators);
    }

    private void RegisterLengthParameterEvents() {
      TreeLengthParameter.ValueChanged += (o, s) => ConfigureOperators(Operators);
      TreeLengthParameter.Value.ValueChanged += (o, s) => ConfigureOperators(Operators);
    }

    private void RegisterDepthParameterEvents() {
      TreeDepthParameter.ValueChanged += (o, s) => ConfigureOperators(Operators);
      TreeDepthParameter.Value.ValueChanged += (o, s) => ConfigureOperators(Operators);
    }

    #region Operator discovery
    private static readonly IEnumerable<Type> encodingSpecificOperatorTypes;

    static SymbolicExpressionTreeEncoding() {
      encodingSpecificOperatorTypes = new List<Type>
      {
        typeof(ISymbolicExpressionTreeOperator),
        typeof(ISymbolicExpressionTreeCreator),
        typeof(ISymbolicExpressionTreeCrossover),
        typeof(ISymbolicExpressionTreeManipulator)
      };
    }

    private void DiscoverOperators() {
      var assembly = typeof(ISymbolicExpressionTreeOperator).Assembly;
      var discoveredTypes = ApplicationManager.Manager.GetTypes(encodingSpecificOperatorTypes, assembly, true, false, false);
      var operators = discoveredTypes.Select(t => (IOperator)Activator.CreateInstance(t));
      var newOperators = operators.Except(Operators, new TypeEqualityComparer<IOperator>()).ToList();

      ConfigureOperators(newOperators);
      foreach (var @operator in newOperators)
        AddOperator(@operator);
    }
    #endregion

    #region Specific operator wiring
    private void ConfigureCreators(IEnumerable<ISymbolicExpressionTreeCreator> creators) {
      foreach (var creator in creators) {
        creator.SymbolicExpressionTreeParameter.ActualName = Name;
        // creator should have depth and length parameters?
      }
    }

    private void ConfigureCrossovers(IEnumerable<ISymbolicExpressionTreeCrossover> crossovers) {
      foreach (var crossover in crossovers) {
        crossover.ParentsParameter.ActualName = Name;
        crossover.ChildParameter.ActualName = Name;
      }
    }

    private void ConfigureManipulators(IEnumerable<ISymbolicExpressionTreeManipulator> manipulators) {
      foreach (var manipulator in manipulators) {
        manipulator.SymbolicExpressionTreeParameter.ActualName = Name;
        manipulator.SymbolicExpressionTreeParameter.Hidden = true;
      }
    }
    #endregion
  }

  public static class IndividualExtensionMethods {
    public static ISymbolicExpressionTree SymbolicExpressionTree(this Individual individual) {
      var encoding = individual.GetEncoding<SymbolicExpressionTreeEncoding>();
      return individual.SymbolicExpressionTree(encoding.Name);
    }

    public static ISymbolicExpressionTree SymbolicExpressionTree(this Individual individual, string name) {
      return (ISymbolicExpressionTree)individual[name];
    }
  }
}