CGAL users discussion list

[Илья Палачев <>]

Hi Quentin,

I'm using file halfspaces_intersection.h that was published by you here:
http://cgal-discuss.949826.n4.nabble.com/How-to-efficiently-compute-intersection-of-half-planes-td4657312.html

It seems to me that there is a bug in it. There is a function that constructs 
duals of given planes, constructs a convex hull, and then maps polyhedron 
them back to primal space.
Inside the dual polyhedron construction there is the following code:


>       typename CGAL::Polyhedron_incremental_builder_3<HDS> B( hds, true);
>
>       B.begin_surface(_primal.size_of_facets(),
>                       _primal.size_of_vertices(),
>                       _primal.size_of_vertices());

When I try to run function halfspaces_intersection in my project the 
following error occurs:

> CGAL::Polyhedron_incremental_builder_3<HDS>::
> lookup_halfedge(): capacity error: more than 490 halfedges added while 
> creating facet39.

So I suggest to change it as follows:

>      typename CGAL::Polyhedron_incremental_builder_3<HDS> B( hds, true);
>
>      B.begin_surface(_primal.size_of_facets(),
>                      _primal.size_of_vertices(),
>                      _primal.size_of_halfedges());

After this change the function begins to work.

I have tried to find whether anybody else use this function, but have found 
only this repo at GitHub:
https://github.com/mrgt/voronoi_covariance
The author of it is Quentin.

To all:
Is there any official way of fast and efficient computation of halfspaces 
intersections? Was it added to CGAL release?

--
Best regards,
Ilya Palachev