On Jan 17, 2012 2:45 AM, "Simon King" <simon.k...@uni-jena.de> wrote:
>
> Hi!
>
> Currently, I try to fix several memory leaks, namely at trac ticket
> #715, #11521, #12215 and #12313. The common idea is: Use weak
> references for the caches (in particular for caching coercions and
> actions), so that stuff can be collected once it is no more used.
>
> But of course it would be easy to overdo it. For example, with the
> current patch from #715, the following computation involves the
> creation of 481 actions, while it only needs 320 actions without the
> patch:
>
> E = J0(46).endomorphism_ring()
> g = E.gens()
>
> So, in that example, actions seem to be garbage collected although
> they will be used again. However, other examples involving elliptic
> curves (e.g., EllipticCurve('960d1').prove_BSD()) are fine, the same
> number of actions is created with or without the patch.
>
> Now I wonder what you would recommend to do?
>
> * Is there a Python package that provides "soft" references (that is
> stronger than a weak reference)? That would be a good solution, but
> google has not been able to find it.
>
> * Should I try to trace down "E.gens()" and add a reference to some
> parent in an appropriate location, so that the 160 actions in the
> example above are prevented from being collected? That would solve the
> particular problem, but there is no guarantee that it is the only
> example of that type.
>
> * Should I modify my weak version of
> `sage.structure.coerce_dict.TripleDict` so that strong references are
> used in the first place, but so that the oldest references are
> "weakened" when the dictionary grows bigger than a certain threshold?
> That is likely to fix the example above and other types of examples as
> well, but may create an overhead.
>
> * Should I consider it as the price to pay for fixing memory leaks?
Just out of curiosity, what is the impact on speed?
>
> Best regards,
> Simon
>
> --
> To post to this group, send an email to sage-devel@googlegroups.com
> To unsubscribe from this group, send an email to
sage-devel+unsubscr...@googlegroups.com
> For more options, visit this group at
http://groups.google.com/group/sage-devel
> URL: http://www.sagemath.org
--
To post to this group, send an email to sage-devel@googlegroups.com
To unsubscribe from this group, send an email to
sage-devel+unsubscr...@googlegroups.com
For more options, visit this group at http://groups.google.com/group/sage-devel
URL: http://www.sagemath.org
