itkDistanceMetric.h

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/*=========================================================================
 *
 *  Copyright Insight Software Consortium
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *         http://www.apache.org/licenses/LICENSE-2.0.txt
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 *=========================================================================*/
#ifndef __itkDistanceMetric_h
#define __itkDistanceMetric_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 =
        NumericTraits<MeasurementVectorType>::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.hxx"
#endif

#endif