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

  Program:   Insight Segmentation & Registration Toolkit
  Module:    $RCSfile: itkExpectationMaximizationMixtureModelEstimator.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 __itkExpectationMaximizationMixtureModelEstimator_h
#define __itkExpectationMaximizationMixtureModelEstimator_h

#include "itkMembershipFunctionBase.h"
#include "itkMixtureModelComponentBase.h"
#include "itkGaussianMembershipFunction.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 TSample                                 SampleType;
  typedef typename TSample::MeasurementType       MeasurementType;
  typedef typename TSample::MeasurementVectorType MeasurementVectorType;


  typedef GaussianMembershipFunction< MeasurementVectorType > 
                                                   GaussianMembershipFunctionType;

  typedef typename GaussianMembershipFunctionType::Pointer 
                                                   GaussianMembershipFunctionPointer;

  typedef MembershipFunctionBase< MeasurementVectorType > MembershipFunctionType;
  typedef typename MembershipFunctionType::ConstPointer   MembershipFunctionPointer;
  typedef std::vector< MembershipFunctionPointer >        MembershipFunctionVectorType;
  typedef SimpleDataObjectDecorator<
    MembershipFunctionVectorType >                        MembershipFunctionVectorObjectType;
  typedef typename 
    MembershipFunctionVectorObjectType::Pointer           MembershipFunctionVectorObjectPointer;

  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);
  const ProportionVectorType& GetInitialProportions() const;

  const ProportionVectorType& GetProportions() const;

  typedef SimpleDataObjectDecorator<
  ProportionVectorType>                 MembershipFunctionsWeightsArrayObjectType;
  typedef typename 
    MembershipFunctionsWeightsArrayObjectType::Pointer   MembershipFunctionsWeightsArrayPointer;

  const MembershipFunctionsWeightsArrayObjectType * GetMembershipFunctionsWeightsArray() const;

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

  int GetCurrentIteration() 
    { 
    return m_CurrentIteration;
    }

  int AddComponent(ComponentType* component);

  unsigned int GetNumberOfComponents() const;

  void Update();

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

  TERMINATION_CODE GetTerminationCode() const;

  ComponentMembershipFunctionType* GetComponentMembershipFunction(int componentIndex) const;

  const MembershipFunctionVectorObjectType * GetOutput() const; 

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

  bool CalculateDensities();
  double CalculateExpectation() const;
  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;

  MembershipFunctionVectorObjectPointer   m_MembershipFunctionsObject;
  MembershipFunctionsWeightsArrayPointer  m_MembershipFunctionsWeightArrayObject;
}; // end of class


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


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

#endif

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