Em 1 de junho de 2011 18:22, Paulo César Pereira de Andrade
<paulo.cesar.pereira.de.andr...@gmail.com> escreveu:
> If I understand it correctly, at least for this particular case:
>
> sage/libs/singular/groebner_strategy.pyx:GroebnerStrategy(SageObject)._parent
> =>
> sage/rings/polynomial/multi_polynomial_libsingular.pyx:MPolynomialRing_libsingular(MPolynomialRing_generic)
>
> and the _parent field has a __dealloc__ as:
> singular_ring_delete(self._ring) while the GroebnerStrategy
> __dealloc__ deferences _parent._ring.
>
> So, again if I understand correctly, the crash is happening because
> MPolynomialRing_libsingular:__deallocate__ should be called
> after pyx:GroebnerStrategy:__deallocate__, but in python 2.7
> this is not happening, as the order is not guaranteed, and
> apparently just happens to be in the correct order with
> python 2.6.
Sorry for replying to myself, but actually, it should be quite
simple to have it functional, just that it must be done in a case
by case approach. Something like:
GroebnerStrategy():
__new__:
...
the_ring_handle = ...
incref(the_ring_handle)
__del__:
...
decref(the_ring_handle)
del the_ring_handle ## requirement of this depends on semantics
MPolynomialRing_libsingular():
__new__:
...
the_ring_ptr = ...
__del__:
if (refcnt(self) <= 0) ## how to do this in python? check if
== 1? or do not use python reference counter?
free(the_ring_ptr)
This should be easy for python internal experts to
implement (I can try to experiment with that, but I do
not know much of python and only do mark&sweep :-)
Paulo
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