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[Jan Rüegg <>]

I tried using a Delaunay_Triangulation_2 in a multithreaded environment. I'm
using arch linux, 64-bit, and CGAL 3.9-2, boost 1.48.0-2

My code is something like this:

---------------------------------------------------------------------------------------

#include <CGAL/Exact_predicates_inexact_constructions_kernel.h>
#include <CGAL/Delaunay_triangulation_2.h>
#include <CGAL/Triangulation_vertex_base_with_info_2.h>
#include <CGAL/Triangulation_face_base_with_info_2.h>

typedef CGAL::Triangulation_vertex_base_with_info_2<voronoi_data, K> Vb;
typedef CGAL::Triangulation_face_base_with_info_2<face_data, K> Fb;
typedef CGAL::Triangulation_data_structure_2<Vb, Fb> Tds;
typedef CGAL::Delaunay_triangulation_2<K, Tds> Triangulation;

...

void GetColor(Triangulation *t, ...) {
 ...
  Vertex new_v = t->insert(current_point);
  t->remove(new_v);
  ...
}

...

void main() {

#pragma omp parallel for
  // Reconstruct image
  for (int y = 0; y < height_; y++) {
    for (int x = 0; x < width_; x++) {
      GetColor(&(ts_[omp_get_thread_num()]), ...);
    }
  }

...
}

---------------------------------------------------------------------------------------

Here, ts_ is a vector of "Triangulation", where each triangulation is
independently set up. That means, each thread has its OWN cgal objects!

When I run this, I get a segmentation fault. However, using:
#pragma omp critical
  t->remove(new_v);

instead, makes it work! That means, the remove function must do something
that is not thread-safe, though every thread operates on its own
triangulation...

Regards
Jan Rüegg



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