Numerics/Statistics/itkExpectationMaximizationMixtureModelEstimator.h

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

  Program:   Insight Segmentation & Registration Toolkit
  Module:    $RCSfile: itkExpectationMaximizationMixtureModelEstimator.h,v $
  Language:  C++
  Date:      $Date: 2009-03-04 15:23:47 $
  Version:   $Revision: 1.13 $

  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 __itkExpectationMaximizationMixtureModelEstimator_h
#define __itkExpectationMaximizationMixtureModelEstimator_h

#include "itkMembershipFunctionBase.h"
#include "itkMixtureModelComponentBase.h"

namespace itk { 
namespace Statistics {

template< class TSample >
class ITK_EXPORT ExpectationMaximizationMixtureModelEstimator : public Object
{
public:
  typedef ExpectationMaximizationMixtureModelEstimator Self;
  typedef Object                                       Superclass;
  typedef SmartPointer< Self >                         Pointer;
  typedef SmartPointer<const Self>                     ConstPointer;

  itkTypeMacro(ExpectationMaximizationMixtureModelEstimator,
               Object);
  itkNewMacro(Self);

  typedef typename TSample::MeasurementType       MeasurementType;
  typedef typename TSample::MeasurementVectorType MeasurementVectorType;

  typedef MixtureModelComponentBase< TSample > ComponentType;

  typedef std::vector< ComponentType* > ComponentVectorType;

  typedef MembershipFunctionBase< MeasurementVectorType > 
  ComponentMembershipFunctionType;

  typedef Array< double > ProportionVectorType;

  void SetSample(const TSample* sample);

  const TSample* GetSample() const;

  void SetInitialProportions(ProportionVectorType &propotion);
  ProportionVectorType* GetInitialProportions();

  ProportionVectorType* GetProportions();

  void SetMaximumIteration(int numberOfIterations);
  int GetMaximumIteration();

  int GetCurrentIteration() 
    { return m_CurrentIteration; }

  int AddComponent(ComponentType* component);

  unsigned int GetNumberOfComponents();

  void Update();

  enum TERMINATION_CODE { CONVERGED = 0, NOT_CONVERGED = 1 };

  TERMINATION_CODE GetTerminationCode();

  ComponentMembershipFunctionType* GetComponentMembershipFunction(int componentIndex);

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

  bool CalculateDensities();
  double CalculateExpectation();
  bool UpdateComponentParameters();
  bool UpdateProportions();

  void GenerateData();

private:
  const TSample* m_Sample;

  int                  m_MaxIteration;
  int                  m_CurrentIteration;
  TERMINATION_CODE     m_TerminationCode;
  ComponentVectorType  m_ComponentVector;
  ProportionVectorType m_InitialProportions;
  ProportionVectorType m_Proportions;
}; // end of class


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


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

#endif