Review/Statistics/itkChiSquareDistribution.h

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

  Program:   Insight Segmentation & Registration Toolkit
  Module:    $RCSfile: itkChiSquareDistribution.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 __itkChiSquareDistribution_h
#define __itkChiSquareDistribution_h

#include "itkProbabilityDistribution.h"
#include "itkNumericTraits.h"

namespace itk { 
namespace Statistics {

class ITK_EXPORT ChiSquareDistribution :
    public ProbabilityDistribution
{
public:
  typedef ChiSquareDistribution    Self;
  typedef ProbabilityDistribution  Superclass;
  typedef SmartPointer<Self>       Pointer;
  typedef SmartPointer<const Self> ConstPointer;

  itkTypeMacro(ChiSquareDistribution, ProbabilityDistribution);

  itkNewMacro(Self);

  virtual unsigned long GetNumberOfParameters() const { return 1; }

  virtual double EvaluatePDF(double x) const;

  virtual double EvaluatePDF(double x, const ParametersType&) const;

  virtual double EvaluatePDF(double x, long degreesOfFreedom) const;

  virtual double EvaluateCDF(double x) const;

  virtual double EvaluateCDF(double x, const ParametersType&) const;

  virtual double EvaluateCDF(double x, long degreesOfFreedom) const;

  virtual double EvaluateInverseCDF(double p) const;

  virtual double EvaluateInverseCDF(double p, const ParametersType&) const;

  virtual double EvaluateInverseCDF(double p, long degreesOfFreedom) const;

  virtual void SetDegreesOfFreedom(long);

  virtual long GetDegreesOfFreedom() const;

  virtual bool HasMean() const { return true; }

  virtual double GetMean() const;

  virtual bool HasVariance() const { return true; }

  virtual double GetVariance() const;

    
  static double PDF(double x, const ParametersType&);

  static double PDF(double x, long degreesOfFreedom);

  static double CDF(double x, const ParametersType&);

  static double CDF(double x, long degreesOfFreedom);

  static double InverseCDF(double p, const ParametersType&);

  static double InverseCDF(double p, long degreesOfFreedom);

protected:
  ChiSquareDistribution(void);
  virtual ~ChiSquareDistribution(void) {}

  void PrintSelf(std::ostream& os, Indent indent) const;

private:
  ChiSquareDistribution(const Self&); //purposely not implemented
  void operator=(const Self&); //purposely not implemented
  
}; // end of class

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

#endif