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 itkVectorAnisotropicDiffusionFunction_h
  #define itkVectorAnisotropicDiffusionFunction_h
  
  #include "itkAnisotropicDiffusionFunction.h"
  #include "itkVector.h"
  
  namespace itk
  {
  /** \class VectorAnisotropicDiffusionFunction
   *
   * This class implements a vector-valued version of
   * AnisotropicDiffusionFunction.  Typically in vector-valued diffusion, vector
   * components are diffused independently of one another using a conductance
   * term that is linked across the components. Refer to the the documentation of
   * AnisotropicDiffusionFunction for an overview of anisotropic diffusion.  The
   * way that the conductance term is calculated is specific to the specific type
   * of diffusion function.
   *
   * \par Data type requirements
   * This filter was designed to process itk::Images of itk::Vector type.  The code
   * relies on various type alias and overloaded operators defined in itk::Vector.
   * It is perfectly reasonable, however, to apply this filter to images of other,
   * user-defined types as long as the appropriate type alias and operator overloads
   * are in place.  As a general rule, follow the example of itk::Vector in
   * defining your data types.
   *
   *  \ingroup FiniteDifferenceFunctions
   *  \ingroup ImageEnhancement
   *
   * \sa AnisotropicDiffusionFunction
   * \sa ScalarAnisotropicDiffusionFunction
   *
   * \ingroup ITKAnisotropicSmoothing
   */
  template< typename TImage >
  class ITK_TEMPLATE_EXPORT VectorAnisotropicDiffusionFunction:
    public AnisotropicDiffusionFunction< TImage >
  {
  public:
    ITK_DISALLOW_COPY_AND_ASSIGN(VectorAnisotropicDiffusionFunction);
  
    /** Standard class type aliases. */
    using Self = VectorAnisotropicDiffusionFunction;
    using Superclass = AnisotropicDiffusionFunction< TImage >;
    using Pointer = SmartPointer< Self >;
    using ConstPointer = SmartPointer< const Self >;
  
    /** Run-time type information (and related methods) */
    itkTypeMacro(VectorAnisotropicDiffusionFunction,
                 AnisotropicDiffusionFunction);
  
    /** Inherit some parameters from the superclass type */
    using ImageType = typename Superclass::ImageType;
    using PixelType = typename Superclass::PixelType;
    using TimeStepType = typename Superclass::TimeStepType;
    using RadiusType = typename Superclass::RadiusType;
    using NeighborhoodType = typename Superclass::NeighborhoodType;
  
    /** Inherit some parameters from the superclass type */
    static constexpr unsigned int ImageDimension = Superclass::ImageDimension;
    static constexpr unsigned int VectorDimension = PixelType::Dimension;
  
    /** Compute the average gradient magnitude squared. */
    void CalculateAverageGradientMagnitudeSquared(TImage *) override;
  
  protected:
    VectorAnisotropicDiffusionFunction() = default;
    ~VectorAnisotropicDiffusionFunction() override = default;
    void PrintSelf(std::ostream & os, Indent indent) const override
    { Superclass::PrintSelf(os, indent); }
  };
  } // end namespace itk
  
  #ifndef ITK_MANUAL_INSTANTIATION
  #include "itkVectorAnisotropicDiffusionFunction.hxx"
  #endif
  
  #endif
  