itkCrossHelper.h

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/*=========================================================================
 *
 *  Copyright NumFOCUS
 *
 *  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
 *
 *         https://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 itkCrossHelper_h
#define itkCrossHelper_h
 
#include "itkNumericTraits.h"
 
namespace itk
{
template <typename TVector>
class CrossHelper
{
public:
  using VectorType = TVector;
  using ValueType = typename VectorType::ValueType;
 
  static constexpr unsigned int Dimension = VectorType::Dimension;
 
  VectorType
  operator()(const VectorType & iU, const VectorType & iV) const
  {
    VectorType oCross;
 
    if constexpr (Dimension > 2)
    {
      oCross[0] = iU[1] * iV[2] - iV[1] * iU[2];
      oCross[1] = iV[0] * iU[2] - iU[0] * iV[2];
      oCross[2] = iU[0] * iV[1] - iV[0] * iU[1];
 
      if constexpr (Dimension > 3)
      {
        for (unsigned int dim = 3; dim < Dimension; ++dim)
        {
          oCross[dim] = 0.0;
        }
      }
    }
    else
    {
      oCross.Fill(0.);
    }
 
    return oCross;
  }
};
} // namespace itk
 
#endif