CGAL users discussion list

[Jayesh Salvi <>]

Ok,

I've made some progress on this.

The wild behavior was probably due to our memory allocation bugs.
After replacing malloc, by calloc the erratic behavior went away and I
got a nice segmentation fault. Here is the stack trace:

(gdb) bt
#0  0xb7796cf5 in
CGAL::SNC_FM_decorator<CGAL::SNC_structure<CGAL::Epeck,
CGAL::SNC_indexed_items, bool>
>::create_facet_objects(CGAL::Plane_3<CGAL::Epeck> const&,
std::_List_iterator<CGAL::Object>, std::_List_iterator<CGAL::Object>)
const
    () from build/libcsgop.so
    #1  0xb7783dc7 in
CGAL::SNC_external_structure<CGAL::SNC_indexed_items,
CGAL::SNC_structure<CGAL::Epeck, CGAL::SNC_indexed_items, bool>
>::categorize_facet_cycles_and_create_facets() const () from
build/libcsgop.so
    #2  0xb7789fcb in void
CGAL::SNC_external_structure<CGAL::SNC_indexed_items,
CGAL::SNC_structure<CGAL::Epeck, CGAL::SNC_indexed_items, bool>
>::build_after_binary_operation<CGAL::ID_support_handler<CGAL::SNC_indexed_items,
CGAL::SNC_decorator<CGAL::SNC_structure<CGAL::Epeck,
CGAL::SNC_indexed_items, bool> > >
>(CGAL::ID_support_handler<CGAL::SNC_indexed_items,
CGAL::SNC_decorator<CGAL::SNC_structure<CGAL::Epeck,
CGAL::SNC_indexed_items, bool> > >&) () from build/libcsgop.so
    #3  0xb7775484 in void
CGAL::Binary_operation<CGAL::SNC_structure<CGAL::Epeck,
CGAL::SNC_indexed_items, bool>
>::operator()<CGAL::Nef_polyhedron_3<CGAL::Epeck,
CGAL::SNC_indexed_items,
bool>::OR>(CGAL::SNC_point_locator<CGAL::SNC_decorator<CGAL::SNC_structure<CGAL::Epeck,
CGAL::SNC_indexed_items, bool> > >*, CGAL::SNC_structure<CGAL::Epeck,
CGAL::SNC_indexed_items, bool> const&,
CGAL::SNC_point_locator<CGAL::SNC_decorator<CGAL::SNC_structure<CGAL::Epeck,
CGAL::SNC_indexed_items, bool> > > const*,
CGAL::SNC_structure<CGAL::Epeck, CGAL::SNC_indexed_items, ---Type
<return> to continue, or q <return> to quit---
    bool> const&,
CGAL::SNC_point_locator<CGAL::SNC_decorator<CGAL::SNC_structure<CGAL::Epeck,
CGAL::SNC_indexed_items, bool> > > const*,
CGAL::Nef_polyhedron_3<CGAL::Epeck, CGAL::SNC_indexed_items, bool>::OR
const&) () from build/libcsgop.so
    #4  0xb776e6a6 in CGAL::Nef_polyhedron_3<CGAL::Epeck,
CGAL::SNC_indexed_items,
bool>::join(CGAL::Nef_polyhedron_3<CGAL::Epeck,
CGAL::SNC_indexed_items, bool> const&) const () from build/libcsgop.so
    #5  0xb7769efc in CGAL::Nef_polyhedron_3<CGAL::Epeck,
CGAL::SNC_indexed_items,
bool>::operator+=(CGAL::Nef_polyhedron_3<CGAL::Epeck,
CGAL::SNC_indexed_items, bool> const&) () from build/libcsgop.so
    #6  0xb7764308 in csgop () from build/libcsgop.so
... application specific frames ...

Does that give any clue?
--
Jayesh



On Tue, May 31, 2011 at 7:15 PM, Jayesh Salvi 
<>
 wrote:
> Let me see if I can put together some minimal c++ code to demo this.
> --
> Jayesh
>
>
>
> On Tue, May 31, 2011 at 11:31 AM, Sebastien Loriot (GeometryFactory)
> <>
>  wrote:
>> Any complete minimal example showing the problem?
>>
>> S.
>>
>> Jayesh Salvi wrote:
>>>
>>> ^ Bump ^
>>>
>>> Any thoughts?
>>> --
>>> Jayesh
>>>
>>>
>>>
>>> On Sun, May 29, 2011 at 4:43 PM, Jayesh Salvi 
>>> <>
>>> wrote:
>>>>
>>>> Hello,
>>>>
>>>> In my program I am creating two polyhedrons from two meshes (In this
>>>> case a cube and a sphere). Then I convert them to Nef Polyhedra and
>>>> apply union (+) operation on them. I then convert the returned Nef
>>>> Polyhedron into a Polyhedron_3, but before doing that I run
>>>> is_simple() check (just so that if it is not simple, I can generate an
>>>> error message, instead of assertion failure crash during the
>>>> conversion process).
>>>>
>>>> In this particular case - with a cube and sphere of specific
>>>> geometries - I observed that after some time the program starts
>>>> occupying a lot of memory and consumes most of the CPU. From the top
>>>> utility, I can see that the process is taking >90% memory and >90%
>>>> CPU. To see what's going on, I put cout statements at various places
>>>> to see during which part of the program does this start to happen. I
>>>> was surprised to find out that this happens when I call is_simple()
>>>> check on the nef polyhedron. At this point either I have to kill the
>>>> process or the system terminates it.
>>>>
>>>> I tried to run the program through valgrind, but as I read elsewhere
>>>> valgrind can't be used with CGAL programs because of floating point
>>>> issues.
>>>>
>>>> Do you have any suggestions how can I proceed to debug this?
>>>>
>>>> Thanks in advance.
>>>>
>>>> (My project is available at http://jayesh3.github.com/cadmium/ I can
>>>> provide instructions on how to reproduce the issue, if you need)
>>>> --
>>>> Jayesh
>>>>
>>>
>>
>>
>> --
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>