Review/Statistics/itkDistanceMetric.h

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

  Program:   Insight Segmentation & Registration Toolkit
  Module:    $RCSfile: itkDistanceMetric.h,v $
  Language:  C++
  Date:      $Date: 2009-05-02 05:43:55 $
  Version:   $Revision: 1.1 $

  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.

=========================================================================*/
#ifndef __itkDistanceMetric_h
#define __itkDistanceMetric_h

#include "itkArray.h"
#include "itkFunctionBase.h"
#include "itkMeasurementVectorTraits.h"

namespace itk  { 
namespace Statistics  {

template< class TVector >
class ITK_EXPORT DistanceMetric : public FunctionBase< TVector, double  >
{
public:
  typedef DistanceMetric                    Self;
  typedef FunctionBase< TVector, double >   Superclass;
  typedef SmartPointer< Self >              Pointer;
  typedef SmartPointer<const Self>          ConstPointer;

  typedef TVector                           MeasurementVectorType;

  typedef unsigned int                      MeasurementVectorSizeType;

  itkTypeMacro(DistanceMetric, FunctionBase);

  typedef Array< double > OriginType;

  void SetOrigin(const OriginType& x);
  itkGetConstReferenceMacro(Origin, OriginType);

  virtual double Evaluate(const MeasurementVectorType &x) const = 0;

  virtual double Evaluate(const MeasurementVectorType &x1, 
                          const MeasurementVectorType &x2) const = 0;

  virtual void SetMeasurementVectorSize( MeasurementVectorSizeType s )
    {
    // Test whether the vector type is resizable or not
    MeasurementVectorType m;
    if( MeasurementVectorTraits::IsResizable( m ) )
      {
      // then this is a resizable vector type
      //
      // if the new size is the same as the previou size, just return
      if( s == this->m_MeasurementVectorSize )
        {
        return;
        }
      else
        {
        this->m_MeasurementVectorSize = s;
        this->Modified();
        }
      }
    else
      {
      // If this is a non-resizable vector type
      MeasurementVectorType m3;
      MeasurementVectorSizeType defaultLength = MeasurementVectorTraits::GetLength( m3 );
      // and the new length is different from the default one, then throw an exception
      if( defaultLength != s )
        {
        itkExceptionMacro("Attempting to change the measurement \
                           vector size of a non-resizable vector type");
        }
      }
    }

  itkGetConstMacro( MeasurementVectorSize, MeasurementVectorSizeType ); 

protected:
  DistanceMetric();
  virtual ~DistanceMetric() {}
  void PrintSelf(std::ostream& os, Indent indent) const;

private:

  OriginType m_Origin;

  MeasurementVectorSizeType       m_MeasurementVectorSize;
}; // end of class

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

#ifndef ITK_MANUAL_INSTANTIATION
#include "itkDistanceMetric.txx"
#endif

#endif