1 /*========================================================================= 2 * 3 * Copyright Insight Software Consortium 4 * 5 * Licensed under the Apache License, Version 2.0 (the "License"); 6 * you may not use this file except in compliance with the License. 7 * You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0.txt 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 * 17 *=========================================================================*/ 18 #ifndef itkForwardDifferenceOperator_h 19 #define itkForwardDifferenceOperator_h 20 21 #include "itkNeighborhoodOperator.h" 22 23 namespace itk 24 { 25 /** 26 * \class ForwardDifferenceOperator 27 * \brief Operator whose inner product with a neighborhood returns 28 * a "half" derivative at the center of the neighborhood. 29 * 30 * ForwardDifferenceOperator uses forward differences 31 * i.e. F(x+1) - F(x) to calculate a "half" derivative useful, among 32 * other things, in solving differential equations. It is a directional 33 * NeighborhoodOperator that should be applied to a Neighborhood using the 34 * inner product. 35 * 36 * \ingroup Operators 37 * \ingroup ITKCommon 38 * 39 * \wiki 40 * \wikiexample{Operators/ForwardDifferenceOperator,Create a forward difference kernel} 41 * \endwiki 42 */ 43 template< typename TPixel, unsigned int VDimension = 2, 44 typename TAllocator = NeighborhoodAllocator< TPixel > > 45 class ITK_TEMPLATE_EXPORT ForwardDifferenceOperator: 46 public NeighborhoodOperator< TPixel, VDimension, TAllocator > 47 { 48 public: 49 /** Standard class type aliases. */ 50 using Self = ForwardDifferenceOperator; 51 using Superclass = NeighborhoodOperator< TPixel, VDimension, TAllocator >; 52 53 using PixelType = typename Superclass::PixelType; 54 55 /** Constructor. */ 56 ForwardDifferenceOperator() = default; 57 58 /** Copy constructor */ ForwardDifferenceOperator(const Self & other)59 ForwardDifferenceOperator(const Self & other): 60 NeighborhoodOperator< TPixel, VDimension, TAllocator >(other) {} 61 62 /** Assignment operator */ 63 Self & operator=(const Self & other) 64 { 65 Superclass::operator=(other); 66 return *this; 67 } 68 69 protected: 70 /** Necessary to work around VC++ compiler bug. */ 71 using CoefficientVector = typename Superclass::CoefficientVector; 72 73 /** Calculates operator coefficients. */ 74 CoefficientVector GenerateCoefficients() override; 75 76 /** Arranges coefficients spatially in the memory buffer. */ Fill(const CoefficientVector & coeff)77 void Fill(const CoefficientVector & coeff) override 78 { 79 this->FillCenteredDirectional(coeff); 80 } 81 }; 82 } // namespace itk 83 84 #ifndef ITK_MANUAL_INSTANTIATION 85 #include "itkForwardDifferenceOperator.hxx" 86 #endif 87 88 #endif 89