CGAL users discussion list

[Gabriel Redner <>]

Hi Nico,

Sounds good.  You may want to email me directly since I don't usually
follow this list.

Thanks,
-Gabe

On Thu, Oct 11, 2012 at 3:26 PM, Nico Kruithof 
<>
 wrote:
> The datasets would be great for performance tests (uniform points in a
> rectangle are so boring). I still had problems with degenerate cases that I
> need to solve first. I'll contact you when I think that I have something
> working.
>
> Nico
>
> On Tue, Oct 9, 2012 at 8:22 PM, Gabriel Redner 
> <>
>  wrote:
>>
>> Hi Nico,
>>
>> Thanks for your message!  Currently my needs are fairly simple - I
>> just need to insert points into a Delaunay triangulation and then
>> iterate over the edges.  The extent of my interaction with CGAL looks
>> like:
>>
>>   typedef CGAL::Exact_predicates_inexact_constructions_kernel Kernel;
>>   typedef CGAL::Triangulation_vertex_base_with_info_2<...stuff...,Kernel>
>> VertexBase;
>>   typedef CGAL::Triangulation_face_base_2<Kernel> FaceBase;
>>   typedef CGAL::Triangulation_data_structure_2<VertexBase,FaceBase>
>> TriangulationDataStructure;
>>   typedef
>> CGAL::Delaunay_triangulation_2<Kernel,TriangulationDataStructure>
>> Triangulation;
>>   typedef typename Triangulation::Point Point;
>>   typedef typename Triangulation::Vertex_handle VertexHandle;
>>   typedef typename Triangulation::Face_handle FaceHandle;
>>   typedef typename Triangulation::Edge Edge;
>>   typedef typename Triangulation::Edge_iterator EdgeIterator;
>>
>>   Triangulation t;
>>   for (...stuff...) {
>>     Vertex h = t.insert(Point(...stuff...));
>>     h->info() = ...stuff...;
>>   }
>>
>>   for (EdgeIterator it = t.edges_begin(); it != t.edges_end(); ++it) {
>>     const Edge e = *it;
>>     const FaceHandle f = e.first;
>>
>>     const VertexHandle v1 = f->vertex(t.cw(e.second));
>>     const VertexHandle v2 = f->vertex(t.ccw(e.second));
>>
>>     do_stuff(v1->info(), v2->info());
>>   }
>>
>> I do not currently anticipate needing anything more complex than this
>> (i.e. no removal etc.).
>>
>> I'd be happy to provide data sets if it would be helpful.  Let me know
>> what range of sizes you are interested in and I can pull something out
>> of my simulation data.
>>
>> I don't need the functionality anytime in particular.  I am currently
>> inserting image points by hand in order to emulate a periodic
>> triangulation, so whenever your code is available it will just enable
>> me to rip out this hack.
>>
>> Thanks,
>> -Gabe
>>
>>
>>
>>
>>
>>
>> On Tue, Oct 9, 2012 at 3:50 AM, Nico Kruithof 
>> <>
>>  wrote:
>> > Hi,
>> >
>> > I'm working on the two dimensional triangulation in my spare time, which
>> > is
>> > rather sparse at the moment. What kind of operations do you need?
>> > Instertion
>> > in a Delaunay triangulation? Do you also want to (re-)move points? I
>> > haven't
>> > thought about a regular triangulation as it is more difficult. Would it
>> > be
>> > possible to get some representative data sets? Can I contact you when I
>> > have
>> > the requested functionality, even if it might take a while or do you
>> > need it
>> > soon?
>> >
>> > Nico
>> >
>> >
>> > On Friday, September 21, 2012, Monique Teillaud wrote:
>> >>
>> >> Le 21/09/12 09:50, Daniel Duque a écrit :
>> >>>
>> >>> On Thursday 20 September 2012 21:59:54 gredner wrote:
>> >>>>
>> >>>> Hi folks,
>> >>>>
>> >>>> I've been a happy user of CGAL's 2D Delaunay triangulation code for
>> >>>> some
>> >>>> time.  However, I'm now in need of code for creating 2D *periodic*
>> >>>> triangulations, and I was very surprised to find that CGAL supports
>> >>>> such
>> >>>> constructions in 3D but not in 2D!  So I'm wondering:
>> >>
>> >>
>> >>> Afaik, currently have to implement a 3D periodic triangulation with
>> >>> all
>> >>> of
>> >>> your points on one plane. It's a waste of space, I know.
>> >>
>> >>
>> >> Indeed, it is a waste of space, and of time as well: if you use the 3D
>> >> periodic triangulation for points that all lie in a plane, then you are
>> >> in a
>> >> 'bad' case when you can never stop computing in the 27-sheeted covering
>> >> space.
>> >> So, you always compute with 27 copies of each point...
>> >>
>> >> Also, using the dummy points in this very specific case would have bad
>> >> effects on the resulting triangulation.
>> >>
>> >> --
>> >> Monique Teillaud
>> >> INRIA Sophia Antipolis - Méditerranée
>> >> http://www.inria.fr/sophia/members/Monique.Teillaud/
>> >>
>> >> --
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>> >> To unsubscribe or access the archives, go to
>> >> https://sympa.inria.fr/sympa/info/cgal-discuss
>> >>
>> >>
>> >
>> >
>> > --
>> > Nico Kruithof
>> > nghk.nl
>> >
>>
>> --
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>>
>>
>
>
>
> --
> Nico Kruithof
> nghk.nl
>