CGAL users discussion list

Hi all,

I am in the process of migrating some Delaunay triangulation/voronoi diagram 
code to use the CGAL implementation. The code uses properties of the delaunay 
triangulation and voronoi diagram in order to produce a variety of metrics 
from output from a forest fire simulation. Many of these simulations result 
extremely large numbers of vertices's, which is where we are running into 
problems.

When built in debug mode, our CGAL backed implementation works correctly, 
however when the project is built in release mode, its a whole other story.

There are two commonly encountered errors, so far we have have not been able 
to determine the reason, or even the circumstances under which, these errors 
occur. In all cases the error occurs as a result of calling the insert(Point) 
method on the triangulation.

Everything is being compiled in Visual Studio 2008.

Rather than posting code from our implementation, I will present two very 
simple loops that seem to trigger the errors. If anybody can help explain 
what is going wrong, or make suggestions as to how to fix it, I would be very 
grateful!
I have been scratching my head with this one for a while now and am running 
low on ideas.

The following includes and typedef's are in the header:

>     #include <CGAL/basic.h>
>     #include <CGAL/Exact_predicates_inexact_constructions_kernel.h>
>     #include <CGAL/Delaunay_triangulation_2.h>
>
>     struct K : CGAL::Exact_predicates_inexact_constructions_kernel {};
>     typedef CGAL::Delaunay_triangulation_2<K>                               
>                              Triangulation;
>     typedef Triangulation::Point                                            
>                             Point;

The follow loop causes an error to be thrown in dblhook.c.

>         Triangulation T;
>         for (long i=1; i<15000; i++) {
>             T.insert(Point(1.0f/i, i%3));
>         }

And, oddly enough, the minor change below changes the error dramatically, in 
particular it now throws a std::length_error exception in "iosfwd", 
specifically in "std::_Traits_helper::length_error()"

>         Triangulation T;
>         for (long i=1; i<15000; i++) {
>             T.insert(Point(1.0f/i, rand()%100));
>         }

And, even weirder, the following modification gets rid of the error 
altogether.

>         Triangulation T;
>         for (long i=1; i<15000; i++) {
>             T.insert(Point(1.0f/i, i%100));
>         }

Note that the results change if we change the number of points added. For a 
sufficiently small set of vertices's, it seems to work every time. As the 
number increases, the likelihood of one of these errors occurring increases 
correspondingly.
Any insight into the source of these problems would be immensely helpful.

-Ryan