source: trunk/sources/HeuristicLab.Functions/FunctionBase.cs @ 528

#region License Information
/* HeuristicLab
 * Copyright (C) 2002-2008 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.Text;
using HeuristicLab.Data;
using HeuristicLab.Core;
using System.Xml;
using HeuristicLab.DataAnalysis;
using HeuristicLab.Constraints;

namespace HeuristicLab.Functions {
  /// <summary>
  /// Functions are like operators except that they do not allow sub-operators and the normal form of evaluation
  /// is to evaluate all children first.
  /// </summary>
  public abstract class FunctionBase : OperatorBase, IFunction {
    public const string INITIALIZATION = "Initialization";
    public const string MANIPULATION = "Manipulation";
    private List<IFunction>[] allowedSubFunctions;
    private int minArity = -1;
    private int maxArity = -1;

    public virtual double Apply(Dataset dataset, int sampleIndex, double[] args) {
      throw new NotImplementedException();
    }

    public virtual void Accept(IFunctionVisitor visitor) {
      visitor.Visit(this);
    }

    public virtual IFunctionTree GetTreeNode() {
      return new BakedFunctionTree(this);
    }

    public int MinArity {
      get {
        if(minArity < 0) RefreshArity();
        return minArity;
      }
    }

    public int MaxArity {
      get {
        if(maxArity < 0) RefreshArity();
        return maxArity;
      }
    }

    private void RefreshArity() {
      minArity = 2; maxArity = 2; // default arity is 2
      foreach(IConstraint constraint in Constraints) {
        NumberOfSubOperatorsConstraint theConstraint = constraint as NumberOfSubOperatorsConstraint;
        if(theConstraint != null) {
          minArity = theConstraint.MinOperators.Data;
          maxArity = theConstraint.MaxOperators.Data;
        }
      }
    }

    public IList<IFunction> AllowedSubFunctions(int index) {
      if(allowedSubFunctions == null) {
        allowedSubFunctions = new List<IFunction>[MaxArity];
        for(int i = 0; i < MaxArity; i++) {
          foreach(IConstraint constraint in Constraints) {
            if(constraint is SubOperatorTypeConstraint) {
              SubOperatorTypeConstraint subOpConstraint = constraint as SubOperatorTypeConstraint;
              if(subOpConstraint.SubOperatorIndex.Data == i) {
                allowedSubFunctions[i] = new List<IFunction>();
                foreach(IFunction f in subOpConstraint.AllowedSubOperators) allowedSubFunctions[i].Add(f);
                break;
              }
            } else if(constraint is AllSubOperatorsTypeConstraint) {
              AllSubOperatorsTypeConstraint subOpConstraint = constraint as AllSubOperatorsTypeConstraint;
              allowedSubFunctions[i] = new List<IFunction>();
              foreach(IFunction f in subOpConstraint.AllowedSubOperators) allowedSubFunctions[i].Add(f);
              break;
            }
          }
        }
      }
      return allowedSubFunctions[index];
    }

    // operator-tree style evaluation is not supported for functions.
    public override IOperation Apply(IScope scope) {
      throw new NotSupportedException();
    }

    private static readonly List<IOperator> emptySubOperatorList = new List<IOperator>();
    public override IList<IOperator> SubOperators {
      get { return emptySubOperatorList; }
    }

    public override void AddSubOperator(IOperator subOperator) {
      throw new NotSupportedException();
    }

    public override bool TryAddSubOperator(IOperator subOperator) {
      throw new NotSupportedException();
    }

    public override bool TryAddSubOperator(IOperator subOperator, int index) {
      throw new NotSupportedException();
    }

    public override bool TryAddSubOperator(IOperator subOperator, int index, out ICollection<IConstraint> violatedConstraints) {
      throw new NotSupportedException();
    }

    public override bool TryAddSubOperator(IOperator subOperator, out ICollection<IConstraint> violatedConstraints) {
      throw new NotSupportedException();
    }

    public override void AddSubOperator(IOperator subOperator, int index) {
      throw new NotSupportedException();
    }

    public override void RemoveSubOperator(int index) {
      throw new NotSupportedException();
    }

    public override bool TryRemoveSubOperator(int index) {
      throw new NotSupportedException();
    }

    public override bool TryRemoveSubOperator(int index, out ICollection<IConstraint> violatedConstraints) {
      throw new NotSupportedException();
    }
  }
}