itkHeavisideStepFunction.h

Go to the documentation of this file.

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

  Program:   Insight Segmentation & Registration Toolkit
  Module:    $RCSfile: itkHeavisideStepFunction.h,v $
  Language:  C++
  Date:      $Date: 2009-05-09 21:06:28 $
  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 __itkHeavisideStepFunction_h
#define __itkHeavisideStepFunction_h

#include "itkHeavisideStepFunctionBase.h"

namespace itk
{

template< class TInput = float, class TOutput = double >
class HeavisideStepFunction : 
 public HeavisideStepFunctionBase< TInput, TOutput >
{
public:
  typedef HeavisideStepFunction                          Self;
  typedef HeavisideStepFunctionBase< TInput, TOutput >   Superclass;
  typedef SmartPointer<Self>                             Pointer;
  typedef SmartPointer<const Self>                       ConstPointer;

  itkNewMacro( Self );
 
  itkTypeMacro( HeavisideStepFunction, HeavisideStepFunctionBase );

  typedef typename Superclass::InputType                        InputType;
  typedef typename Superclass::OutputType                       OutputType;

  virtual OutputType Evaluate( const InputType& input ) const
    {
    return ( input >= 0.0 ) ? 1.0 : 0.0;
    }

  virtual OutputType EvaluateDerivative( const InputType& input ) const
    {
    return ( input == 0.0 ) ? 1.0 : 0.0;
    }

protected:
  HeavisideStepFunction() {}
  virtual ~HeavisideStepFunction() {}

private:
  HeavisideStepFunction(const Self& ); //purposely not implemented
  void operator=(const Self& ); //purposely not implemented

};

}

#endif