CGAL users discussion list

[Stefan Witzel <>]

Dear Mael,

Thank you for this nice explanation! I have in fact run into issues
with non-hyperbolic faces which I had understood mathematically and
thanks to you now understand also on the software level.

Best,
Stefan

Am Fr., 14. Juni 2019 um 08:12 Uhr schrieb Mael
<>:
>
> Hello,
>
> This is usually the case, if you look at the documentation page of e.g.
> Regular_triangulation_2, you'll see a section "Additional Inherited
> Members", which contains exactly what you have in mind (typedefs and
> functions from Triangulation_2).
>
> Hyperbolic_Delaunay_triangulation_2 (HDT2) is a little bit different
> because it inherits Delaunay_triangulation_2 (DT2), but in a private
> way. This is done exactly so that not everything from DT2 is shown in
> the documentation. This is because the simplicies in a HDT2 form only a
> subset of the simplices of a DT2. Thus, we are internally building a DT2
> and the class HDT2 is just a filter on top of the DT2.
>
> You can use the functions from DT2 (or even T2, which DT2 inherits), but
> be careful that you will then be working with the full DT2 structure and
> not the HDT2. You can apply hyperbolic filtering manually via the
> "is_hyperbolic()" family of functions to bring things back to HDT2.
>
> Best,
> Mael
>
> On 13/06/2019 22:15, Stefan Witzel wrote:
> > Hi,
> >
> > Sorry about my last question! In case someone is actually wondering:
> > the answer are face circulators [1]. The documentation would be much
> > more accessible if one could see all the inherited methods somewhere.
> > I was looking at the documentation for
> > Hyperbolic_Delaunay_triangulation_2 and from there it's a bit of a way
> > down to Triangulation_2, especially when you are wondering about the
> > traits and data structures along the way.
> >
> > Best,
> > Stefan
> >
> > [1] 
> > https://doc.cgal.org/latest/Triangulation_2/classCGAL_1_1Triangulation__2.html#a1bda2ab92ccf638bb22fc223ae281b96
> >
> > Am Do., 13. Juni 2019 um 16:32 Uhr schrieb Stefan Witzel 
> > <>:
> >> Hello,
> >>
> >> I do not have any previous experience with cgal and my question is a
> >> rather conceptual one without much technical insight: I would like to
> >> iterate over the faces of a Voronoi diagram and then over the edges of
> >> each face (to obtain a closed polygon); in other words this means to
> >> iterate over the vertices of a Delaunay triangulation and then over
> >> the edges incident with this vertex. Am I right to assume that this is
> >> fundamentally problematic with the default parameters for
> >> Delaunay_triangulation_2 (Triangulation_vertex_base_2,
> >> Triangulation_face_base_2) as a vertex does not ``know'' the edges it
> >> is incident with? Is there a kind of dual assignment that I could use
> >> (like ``(Tessellation_face_base, Tessellation_vertex_base)'')?
> >>
> >> Since tessellations into non-triangles may be more complicated, would
> >> it be a possibility to first produce the (common) barycentric
> >> subdivision?
> >>
> >> Best,
> >> Stefan
>
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