#18250: G.triangles_count speedup
-------------------------+-------------------------------------------------
Reporter: | Owner:
ncohen | Status: needs_review
Type: | Milestone: sage-6.7
enhancement | Resolution:
Priority: major | Merged in:
Component: graph | Reviewers:
theory | Work issues:
Keywords: | Commit:
Authors: | fa6115dc6cdea907dad9c2cd69668f5e71660024
Nathann Cohen | Stopgaps:
Report Upstream: N/A |
Branch: |
public/18250 |
Dependencies: |
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Comment (by vdelecroix):
Replying to [comment:7 ncohen]:
> > Cython does not perform deallocation, it is Python job.
>
> Well if you prefer, but this code is translated into C, and gcc may
notice that the object is totally useless. They must have done something
to keep those Python variables until the end.
Nope. gcc will not do that. An affectation `G = H` is not one instruction
if `H` is a Python object. Cython translates it into something like
{{{
cdef PyObject * G = H;
Py_INCREF(G);
}}}
whick prevents deallocation of H until G is garbage collected (typically
at the end of the function or until a call of `del G`).
Vincent
--
Ticket URL: <http://trac.sagemath.org/ticket/18250#comment:8>
Sage <http://www.sagemath.org>
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