anchor.diff:    public de_casteljau_one_round, evaluate_multi, linearization_error, &
            evaluate_barycentric, evaluate_barycentric_multi, &
            evaluate_cartesian_multi, cross_product, segment_intersection, &
  -         bbox, specialize_curve
  +         bbox, specialize_curve_generic, specialize_curve
   
     ! NOTE: This still relies on .f2py_f2cmap being present
     !       in the directory that build is called from.
  
positive.code:     true_start = curve_start + start * interval_delta
      true_end = curve_start + end_ * interval_delta
  
    end subroutine specialize_curve
  
  end module speedup
  
negative.code: 
    end subroutine bbox
  
    subroutine specialize_curve_generic( &
         nodes, degree, dimension_, start, end_, curve_start, curve_end, &
         new_nodes, true_start, true_end)
  
      ! NOTE: This is a helper for ``specialize_curve`` that works on any degree.
  
      !f2py integer intent(hide), depend(nodes) :: dimension_ = size(nodes, 2)
      real(dp), intent(in) :: nodes(degree + 1, dimension_)
  