CGAL users discussion list

["Vu, Khuong" <>]

Hi there,

I think what you did was good. I got the same thing working with Voronoi 
diagram. I guess it is the problem of Voronoi diagram adapter. 

You can check if it is by constructing the DELAUNAY diagram of the same set 
of input instead of Vornoi diagram. If it runs reasonably fast, then it is 
the Voronoi adapter to have trouble. You can look at the header definition of 
the SegmentDelaunayGraph demo. The declaration should be good for you since 
it deals with no strongly intersection. However, it is Delaunay. Constructing 
the Voronoi still runs pretty slow though.

Please let me know if you need further help. I have written an alternative 
Voronoi adapter, currently just for myself. But I'm now away from my desk.

Khuong
________________________________________
From: Bai 
[]
Sent: Thursday, April 22, 2010 8:01 PM
To: 

Subject: [cgal-discuss] Problems on segment Voronoi diagram

I am constructing Vornoi diagrams using CGAL, the segments are all from a
polygonal line, they are consecutive, and there are
weak intersections as CGAL describes.
  Firstly,I chose MP_Float as the data type for EK, however, the running
time is rather slow,
even slower than the results given in the corresponding papar<< A robust and
efficient implementation for the segment Voronoi diagram>>
in 2004.
 Then, I chose Simple_cartesian<double> as EK, this time the running time is
rather short , however, the checking function is_valid()
returns false. And for segments more than 5000, the program corrupted.
 Could someone give a trait and policy configurtion ,under which I can build
Voronoi diagram of a polygonal line efficiently? Thank you

 The following is my current configuration(under which the program runs
quite slow, if replace EK with Simple_cartesian<double>,
the build time is short but for more than 5000 segments the program
corrupts):
        typedef CGAL::Quotient<CGAL::MP_Float>  ENT;
        typedef CGAL::Simple_cartesian<double>     CK;
        typedef CGAL::Simple_cartesian<ENT>        EK;
        typedef
CGAL::Segment_Delaunay_graph_filtered_traits_2<CK,CGAL::Field_with_sqrt_tag,
EK,  CGAL::Field_tag>  Gt;
        typedef CGAL::Segment_Delaunay_graph_2<Gt>             SDG2;
        typedef CGAL::Segment_Delaunay_graph_adaptation_traits_2<SDG2>
TRAIT;
        typedef
CGAL::Segment_Delaunay_graph_caching_degeneracy_removal_policy_2<SDG2>
POLICY;
        typedef CGAL::Voronoi_diagram_2<SDG2,TRAIT,POLICY> SEG_VD;
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