message: Code review: Add suggested code using NT_converter to simplify the different alpha_complex_filtration computations cases
diff: #include <CGAL/Spatial_sort_traits_adapter_d.h>
  #include <CGAL/property_map.h> // for CGAL::Identity_property_map
  #include <CGAL/version.h> // for CGAL_VERSION_NR
  +#include <CGAL/NT_converter.h>
  #include <Eigen/src/Core/util/Macros.h> // for EIGEN_VERSION_AT_LEAST
  @@ -340,17 +341,12 @@ class Alpha_complex {
  // squared_radius function initialization
  Squared_Radius squared_radius = kernel_.compute_squared_radius_d_object();
  -#if CGAL_VERSION_NR < 1050000000
  - // With CGAL >= 4.11 and < 5.X, CGAL::exact do not work as it is always exact values
  - // This is why it is slow and 5.X is advised
  - alpha_complex_filtration = CGAL::to_double(squared_radius(pointVector.begin(), pointVector.end()));
  -#else // CGAL_VERSION_NR < 1050000000
  - if (exact) {
  - alpha_complex_filtration = CGAL::to_double(CGAL::exact(squared_radius(pointVector.begin(), pointVector.end())));
  - } else {
  - alpha_complex_filtration = CGAL::to_double(squared_radius(pointVector.begin(), pointVector.end()));
  - }
  -#endif //CGAL_VERSION_NR < 1050000000
  + CGAL::NT_converter<typename Geom_traits::FT, Filtration_value> cv;
  + auto sqrad = squared_radius(pointVector.begin(), pointVector.end());
  +#if CGAL_VERSION_NR >= 1050000000
  + if(exact) CGAL::exact(sqrad);
  +#endif
  + alpha_complex_filtration = cv(sqrad);
  }
  complex.assign_filtration(f_simplex, alpha_complex_filtration);
  #ifdef DEBUG_TRACES
  