CGAL users discussion list

["Sebastien Loriot (GeometryFactory)" <>]

On 02/23/2015 03:16 PM, Antonio Carlos Pereira de Azambuja wrote:
> Hello, Sebastien!
>
> I just can't get my test work. I'm trying to test if serial code and
> parallel code performing CGAL::Orthogonal_k_neighbor_search work on 4D.
> Both should return the same results for the same queries. If I run the
> test for some time executing the same test in an outside loop (it means,
> allocating and deallocation everytime) some problems occurs with
> deallocation at some point and a segfault arises.
>
> Considering the statements below are correct:
>
>    i) Cartesian_d<double>::Point_d  inherits from PointCd2
>   ii) PointCd2 inherits from Handle_for<tuple..>
> iii) Handle_for uses reference counters.
>
> I am wondering if the reference counting strategy (in Handle_for) could
> be the cause of this errors?

Indeed, the class Handle_for is not yet thread-safe.
We'll provide soon an official fix for that.

In the meantime you can try the one provided in this mailing list:
https://sympa.inria.fr/sympa/arc/cgal-discuss/2015-01/msg00073.html

Sebastien.

> Thanks
> -- Antonio Azambuja
>
>
>
> 2015-02-12 11:54 GMT-02:00 Sebastien Loriot (GeometryFactory)
> <
>  
> <mailto:>>:
>
>     On 02/12/2015 02:53 PM, Antonio Carlos Pereira de Azambuja wrote:
>
>         Hi,
>
>         I am using CGAL to solve nearest neighbor search in 4 dimensional.
>
>         I would like to know if I can build a single kdtree object and
>         perform
>         parallel searches in each thread of an OMP loop. Each thread has
>         its own
>         search object. The problem could be illustrated by the draft
>         code below:
>
>         int main(void)
>         {
>
>               // create a kdTree from a point cloud
>               CGAL::Orthogonal_k_neighbor___search<Traits>::Tree   *kdTree;
>               kdTree = new
>         CGAL::Orthogonal_k_neighbor___search<Traits>::Tree(
>         points.begin(), points.end() )
>               .
>               .
>               .
>               // perform several searches in an OMP loop
>         #pragma omp parallel .....
>              for (counter =0; ....)
>             {
>                .
>                .
>                CGAL::Cartesian_d<FT>::Point_d query(......); // define a
>         query point
>                CGAL::Orthogonal_k_neighbor___search<Traits>      search(
>         *kdTree,
>         query, 1);
>                .
>                .
>             } //end for
>         }//end main
>
>
>         Thanks in advance for any help.
>         -- Antonio Azambuja
>
>
>     Yes it is.
>
>     Sebastien.
>
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