ITK/Examples/Math/CovariantVectorNorm

#include <itkCovariantVector.h>
 
int main(int, char*[])
{
  typedef itk::CovariantVector<double, 3> VectorType;
  VectorType v;
  v[0] = 1.0;
  v[1] = 2.0;
  v[2] = 3.0;
 
  std::cout << "v: " << v << std::endl;
 
  // norm
  VectorType::RealValueType vnorm = v.GetNorm();
  std::cout << "vnorm: " << vnorm << std::endl;
 
  VectorType::RealValueType vnorm2 = v.GetSquaredNorm();
  std::cout << "vnorm2: " << vnorm2 << std::endl;
 
  VectorType u = v;
 
  // normalization
  v.Normalize();
  std::cout << "v: " << v << std::endl;
 
  // another way to normalize
  if( vnorm != 0. )
    {
    for( unsigned int i = 0; i < u.GetNumberOfComponents(); i++ )
      {
      u[i] /= vnorm;
      }
    }
 
  std::cout << "u: " << u << std::endl;
 
  if( ( u - v ).GetNorm() != 0. )
    {
    return EXIT_FAILURE;
    }
 
  return EXIT_SUCCESS;
}