text: /*=========================================================================
   *
   *  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 itkSqrtImageFilter_h
  #define itkSqrtImageFilter_h
  
  #include "itkUnaryGeneratorImageFilter.h"
  #include "itkMath.h"
  
  namespace itk
  {
  namespace Functor
  {
  /**
   * \class Sqrt
   * \brief
   * \ingroup ITKImageIntensity
   */
  template< typename TInput, typename TOutput >
  class Sqrt
  {
  public:
    Sqrt() {}
    ~Sqrt() {}
    bool operator!=(const Sqrt &) const
    {
      return false;
    }
  
    bool operator==(const Sqrt & other) const
    {
      return !( *this != other );
    }
  
    inline TOutput operator()(const TInput & A) const
    {
      return static_cast<TOutput>( std::sqrt( static_cast<double>(A) ) );
    }
  };
  }
  
  /** \class SqrtImageFilter
   * \brief Computes the square root of each pixel.
   *
   * The computations are performed using std::sqrt(x).
   *
   * \ingroup IntensityImageFilters
   * \ingroup MultiThreaded
   * \ingroup ITKImageIntensity
   */
  template< typename TInputImage, typename TOutputImage >
  class SqrtImageFilter:
    public UnaryGeneratorImageFilter< TInputImage, TOutputImage >
  {
  public:
    ITK_DISALLOW_COPY_AND_ASSIGN(SqrtImageFilter);
  
    /** Standard class type aliases. */
    using Self = SqrtImageFilter;
    using Superclass = UnaryGeneratorImageFilter< TInputImage, TOutputImage >;
    using Pointer = SmartPointer< Self >;
    using ConstPointer = SmartPointer< const Self >;
    using FunctorType = Functor::Sqrt< typename TInputImage::PixelType,
                                       typename TOutputImage::PixelType >;
  
    /** Method for creation through the object factory. */
    itkNewMacro(Self);
  
    /** Runtime information support. */
    itkTypeMacro(SqrtImageFilter,
                 UnaryGeneratorImageFilter);
  
  #ifdef ITK_USE_CONCEPT_CHECKING
    // Begin concept checking
    itkConceptMacro( InputConvertibleToDoubleCheck,
                     ( Concept::Convertible< typename TInputImage::PixelType, double > ) );
    itkConceptMacro( DoubleConvertibleToOutputCheck,
                     ( Concept::Convertible< double, typename TOutputImage::PixelType > ) );
    // End concept checking
  #endif
  
  protected:
    SqrtImageFilter()
      {
  #if !defined( ITK_WRAPPING_PARSER )
        Superclass::SetFunctor(FunctorType());
  #endif
      }
  
    ~SqrtImageFilter() override {}
  };
  } // end namespace itk
  
  #endif
  