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["Hoffmann Michael" <>]

See the quote from the docs below. Did you try sphere_of_spheres? Or Epeck?

Best, Michael

Please note: This class is (almost) obsolete. The class CGAL::Min_sphere_of_spheres_d<Traits> solves a more general problem and is faster then Min_sphere_deven if used only for points as input. Most importantly, CGAL::Min_sphere_of_spheres_d<Traits> has a specialized implementation for floating-point arithmetic which ensures correct results in a large number of cases (including highly degenerate ones). In contrast, Min_sphere_d is not reliable under floating-point computations. The only advantage of Min_sphere_d over CGAL::Min_sphere_of_spheres_d<Traits> is that the former can deal with points in homogeneous coordinates, in which case the algorithm is division-free. Thus, Min_sphere_d might still be an option in case your input number type cannot (efficiently) divide.

On 19 Aug 2020, at 18:52, Raphael Grimm <> wrote:

Hi,
i was playing around with Min_sphere_d and encountered some behavior i do not understand (see attached files).

In both cases my code creates a Min_sphere_d using Min_sphere_annulus_d_traits_3 and Epick and then it inserts three points and prints the radius.

In the first case i used doubles to initialize the Point_3 and the output is correct.
In the second case i used floats to initialize the Point_3 and the output is nan.

The only difference is the type of the values used to initialize the Point_3.
This means the error has to be caused by the differences in accuracy, but this should not really create a difference.

Has anyone any idea why this happens and how i can prevent this problem?
Since the data i am using is represented as floats, I can't really switch everything to double.

I appreciate any help.

Best regards,

Raphael


PS.: I am on master (54f2a119f9598f884f98df9ee1fa63aa07451c4c).



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