/*=========================================================================

  Program:   Insight Segmentation & Registration Toolkit
  Module:    $RCSfile: itkLearningFunctionBase.h,v $
  Language:  C++
  Date:      $Date: 2007/08/17 13:10:57 $
  Version:   $Revision: 1.2 $

  Copyright (c) Insight Software Consortium. All rights reserved.
  See ITKCopyright.txt or http://www.itk.org/HTML/Copyright.htm for details.

     This software is distributed WITHOUT ANY WARRANTY; without even
     the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
     PURPOSE.  See the above copyright notices for more information.

=========================================================================*/
/** \class LearningFunctionBase
 *  \brief The LearningFunctionBase is the base class for all the learning strategies.
 *  These include error back propagation, bp+momentum, conjugte gradient descent, quick prop.
 *  This class specifies how the errors are backpropagated for a layer. They take a LayerBase
 *  object as input and compute the input for the layers input weightset */

#ifndef __itkLearningFunctionBase_h
#define __itkLearningFunctionBase_h

#include "itkLightProcessObject.h"

namespace itk
{
  namespace Statistics
    {

    template<class LayerType, class TTargetVector>
      class LearningFunctionBase : public LightProcessObject
        {
      public:

        typedef LearningFunctionBase Self;
        typedef LightProcessObject Superclass;
        typedef SmartPointer<Self> Pointer;
        typedef SmartPointer<const Self> ConstPointer;

        /** Method for creation through the object factory. */
        itkTypeMacro(LearningFunctionBase, LightProcessObject);

        typedef typename LayerType::ValueType ValueType;

        virtual void Learn(LayerType* layer, ValueType) = 0;
        virtual void Learn(LayerType* layer, TTargetVector error,ValueType) = 0;

      protected:
        LearningFunctionBase() {};
        ~LearningFunctionBase() {};

        /** Method to print the object. */
        virtual void PrintSelf( std::ostream& os, Indent indent ) const
          {
          os << indent << "LearningFunctionBase(" << this << ")" << std::endl;
          Superclass::PrintSelf( os, indent );
          }
        };

    } // end namespace Statistics
} // end namespace itk

#endif
