CGAL users discussion list

[Andreas Fabri <>]

You could determine what primitives intersect in parallel with Epic and

OutputIterator CGAL::AABB_tree< Tr >::all_intersected_primitives	(	const Query &	query,
		OutputIterator	out
	)		const

https://doc.cgal.org/latest/AABB_tree/classCGAL_1_1AABB__tree.html#a9f40594599eded5f9a79f74186710697

and then in a sequential pass compute the intersections.

By the way, did you have a look at the slicer:

https://doc.cgal.org/latest/Polygon_mesh_processing/index.html#title52

Best,

Andreas

On 2/22/2020 11:12 PM, Yifang Zhao wrote:

      But I need to compute the exact intersections between a plane and
      the polyhedron. That’s why I am using epec for aabbtree. Is there
      any solutions to do this? Or it is not possible yet?

Sent from my iPhone

On Feb 22, 2020, at 10:28 PM, Andreas Fabri <> wrote:



Epec is currently not multi-threading safe.
The AABB Tree does not need exact constructions, so we should think
about a way to use the points/triangles/planes for Epic, together with
the face handles of the Polyhedron parameterized with Epec.

andreas

On 2/22/2020 9:55 PM, Yifang Zhao wrote:

I am using EPEC Kernel.

 

 

Sent from Mail for Windows 10

 

From: Andreas Fabri
Sent: 2020年2月22日 21:54
To:
Subject: Re: [cgal-discuss] Heap corruption when constructing AABB tree with OPENMP

 

What kernel do you use?

On 2/22/2020 9:51 PM, Yifang Zhao wrote:

I have a for loop containing approximately 1,000,000 iterations of calling AABBTree.all_intersections() method. Thus, I use #pragma omp parallel for to speed up the program. However, I got an error as "A heap has been corrupted". The cpp file is roughly like the following:

Polyhedron polyhedron;

Facet_tree m_facet_tree(faces(m_polyhedron).first, faces(m_polyhedron).second, m_polyhedon);

#pragma omp parallel for

for (int i = 0; i<100; ++i){

    Plane plane = Plane(1, 0, 0, 0);

    // Compute intersections

    typedef std::vector<Facet_tree::Object_and_primitive_id> Intersections;

    Intersections intersections;

    m_facet_tree.all_intersections(plane, std::back_inserter(intersections));

}

Finally, The program will break here:

    ~Handle()

    {

    if ( PTR && (--PTR->count == 0))

        delete PTR;

    }

What are the possible reasons that cause this problem? Thanks a lot!

Kind Regards,

Yifang Zhao.

 

Sent from Mail for Windows 10

 

-- 
Andreas Fabri, PhD
Chief Officer, GeometryFactory
Editor, The CGAL Project

phone: +33.492.954.912    skype: andreas.fabri

-- 
Andreas Fabri, PhD
Chief Officer, GeometryFactory
Editor, The CGAL Project

phone: +33.492.954.912    skype: andreas.fabri
          
        
      
    
-- 
Andreas Fabri, PhD
Chief Officer, GeometryFactory
Editor, The CGAL Project

phone: +33.492.954.912    skype: andreas.fabri