CGAL users discussion list

[Andreas Fabri <>]

As a follow up I started this WIP pull request. https://github.com/CGAL/cgal/pull/4941

Best,

Andreas

On 8/20/2020 11:22 AM, Hoffmann Michael wrote:

It is not really deprecated in the sense that we plan to remove it eventually, for the reasons given there.

Best, Michael

> On 20 Aug 2020, at 09:04, Raphael Grimm  wrote:
>
> Thanks for the help! Using Min_sphere_of_spheres_d fixed this for me. I only skimmed the documentation and did not see the note.
>
> It would be nice if deprecated functions would be decorated with [[deprecated]] (c++14 feature). if macros are used, this can be done conditionally depending on the c++ standard.
>
> On 19.08.20 19:50, Hoffmann Michael wrote:
> > 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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> > >
> > > <code.cpp>
> > > <output>
> > >           
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> >         
>       

    
-- 
Andreas Fabri, PhD
Chief Officer, GeometryFactory
Editor, The CGAL Project

phone: +33.492.954.912    skype: andreas.fabri