#11521: Use weak references to cache homsets
-------------------------------+--------------------------------------------
Reporter: jpflori | Owner: robertwb
Type: defect | Status: positive_review
Priority: major | Milestone: sage-pending
Component: coercion | Resolution:
Keywords: sd35 | Work issues:
Report Upstream: N/A | Reviewers: Jean-Pierre Flori
Authors: Simon King | Merged in:
Dependencies: #11900 #715 | Stopgaps:
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Old description:
> Originally, this ticket was about the following memory leak when
> computing with elliptic curves:
>
> {{{
> sage: K = GF(1<<55,'t')
> sage: a = K.random_element()
> sage: while 1:
> ....: E = EllipticCurve(j=a); P = E.random_point(); 2*P;
> }}}
> This example is in fact solved by #715. However, while working on that
> ticket, another leak has been found, namely
>
> {{{
> sage: for p in prime_range(10^5):
> ....: K = GF(p)
> ....: a = K(0)
> ....:
> sage: import gc
> sage: gc.collect()
> 0
> }}}
> So, I suggest to start with #715 and solve the second memory leak on top
> of it. It seems that a strong cache for homsets is to blame. I suggest to
> use the weak `TripleDict` instead, which were introduced in #715.
>
> '''To be merged with #715'''. Apply
>
> * the patches from #715
> * [attachment:trac11521_triple_homset.patch]
> * [attachment:trac_11521-reviewer.patch]
New description:
Originally, this ticket was about the following memory leak when computing
with elliptic curves:
{{{
sage: K = GF(1<<55,'t')
sage: a = K.random_element()
sage: while 1:
....: E = EllipticCurve(j=a); P = E.random_point(); 2*P;
}}}
This example is in fact solved by #715. However, while working on that
ticket, another leak has been found, namely
{{{
sage: for p in prime_range(10^5):
....: K = GF(p)
....: a = K(0)
....:
sage: import gc
sage: gc.collect()
0
}}}
So, I suggest to start with #715 and solve the second memory leak on top
of it. It seems that a strong cache for homsets is to blame. I suggest to
use the weak `TripleDict` instead, which were introduced in #715.
'''To be merged with #715'''. Apply
* the patches from #715
* [attachment:trac_11521_homset_weakcache_combined.patch]
--
Comment (by SimonKing):
I have created a combined patch, by folding the two patches (i.e., mine
and Jean-Pierre's reviewer patch).
With #715 and this patch, all doctests pass on my machine. So, from my
perspective, it is a positive review, but we should wait for Jean-Pierre's
results on 32 bit.
For the patchbot:
Apply trac_11521_homset_weakcache_combined.patch
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/11521#comment:131>
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