Sorry Thomas, but _kill_pointed does not solve the issue. It looks like the SWIG wrapper objects are not DECREF'd at all - see the example below, which shows that calling "del" on a shape does not decrease the ref count of the SWIG wrapper object at all:

import gc
import sys
import gc
from OCC.gp import *
from OCC.BRepPrimAPI import *
from OCC.TopExp import *
from OCC.TopoDS import *

w = 0.1
fp1 = (0.,0.,0.)
fp2 = (w,w,w)
mkbox = BRepPrimAPI_MakeBox(gp_Pnt(fp1[0],fp1[1],fp1[2]), gp_Pnt(fp2[0],fp2[1],fp2[2]))
s = mkbox.Shell()


class MemTest(object):
    pass
mem = MemTest()

# The next 3 lines show that _kill_pointed nullifies the underlying shape
print 'before: IsNull=', s.IsNull()
s._kill_pointed()
print 'after: IsNull=', s.IsNull()

print gc.get_count()
print gc.collect()
print gc.get_count()
for o in gc.get_objects():
    if isinstance(o, TopoDS_Shape) or isinstance(o, MemTest):
        print type(o), sys.getrefcount(o)

# The next 2 lines should remove s and mem from gc.get_objects, but it only removes mem!!!
del s
del mem

print gc.get_count()
print gc.collect()
print gc.get_count()
for o in gc.get_objects():
    if isinstance(o, TopoDS_Shape) or isinstance(o, MemTest):
        print type(o), sys.getrefcount(o)


I'm not sure where to go from here.
- Frank


On 17/02/2010 8:29 PM, Thomas Paviot wrote:
2010/2/18 Frank Conradie <fr...@qfin.net <mailto:fr...@qfin.net>>

    Hi guys,


Hi Franck,


    After running into serious memory use issues with our geometric
    processing algorithm, I have done a simple experiment that seems
    to show
    that wrapper garbage collection does not work at all. Try the code
    below, and you should run out of memory in no time:


    import gc
    from OCC.gp import *
    from OCC.BRepPrimAPI import *
    from OCC.TopExp import *

    def TestMemory():
        w = 0.1
        fp1 = (0.,0.,0.)
        fp2 = (w,w,w)
        mkbox = BRepPrimAPI_MakeBox(gp_Pnt(fp1[0],fp1[1],fp1[2]),
    gp_Pnt(fp2[0],fp2[1],fp2[2]))
        s1 = mkbox.Shell()
        e = TopExp_Explorer()
        for i in range(1000000):
            print i
            e.Init(s1, TopAbs_FACE)
            while e.More():
                sh = e.Current()
                e.Next()
            if not (i % 1000):
                print 'Collecting garbage...'
                gc.collect()
        while 1:
            pass


    Not sure if this is a known issue or not,


It's known to be an issue, see:
* http://www.opencascade.org/org/forum/thread_17702/
* the changelog of the 0.4 release

    but it certainly makes the
    wrapper problematic for our current purposes. If you can point me
    at the
    right place in the wrapper generator I can maybe try and help.


The standard python gc module can not be used with pythonOCC: it's perfectly suitable to manage python objects deletion, but fails to properly handle the C++ pointed objects. A GarbageCollector class is available from any pythonOCC module you're using. For instance:

Python 2.6.1 (r261:67515, Jul  7 2009, 23:51:51)
[GCC 4.2.1 (Apple Inc. build 5646)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> from OCC.Standard import *
>>> GarbageCollector
<module 'OCC.GarbageCollector' from '/Library/Python/2.6/site-packages/OCC/GarbageCollector.pyc'>
>>> dir(GarbageCollector)
['GarbageCollector', '__builtins__', '__doc__', '__file__', '__name__', '__package__', 'garbage', 'sys']
>>> GarbageCollector.garbage
<OCC.GarbageCollector.GarbageCollector object at 0x100593e10>
>>> dir(GarbageCollector.garbage)
['__class__', '__delattr__', '__dict__', '__doc__', '__format__', '__getattribute__', '__hash__', '__init__', '__module__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__', '__weakref__', '_collected_objects', 'collect_object', 'get_collected', 'purge']

The source code of this module is here:
http://svn.gna.org/viewcvs/pythonocc/trunk/src/wrapper/GarbageCollector.py?rev=706&view=markup <http://svn.gna.org/viewcvs/pythonocc/trunk/src/wrapper/GarbageCollector.py?rev=706&view=markup>

In a few words, if you want to completely free memory:
GarbageCollector.garbage.purge()

If you want to free one specific object, use the _kill_pointed() method of that object (Nulify, Clear, Destroy won't work).

I'll take time to write a more detailed message tomorrow about that topic.


    Thanks,
    Frank Conradie
    Qfinsoft


All the best,

Thomas


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