#11900: Serious regression caused by #9138
----------------------------------------------------------------------------------------+
Reporter: SimonKing
| Owner: tbd
Type: defect
| Status: needs_work
Priority: critical
| Milestone: sage-4.8
Component: performance
| Keywords: categories regression
Work_issues: Laurent series rings are fields. Add docs. Don't use is_ring and
friends | Upstream: N/A
Reviewer: Jeroen Demeyer, Nicolas M. Thiéry
| Author: Simon King
Merged:
| Dependencies: #9138 #11911
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Old description:
> At [http://groups.google.com/group/sage-
> devel/browse_thread/thread/d885434ba9c22d66 sage-devel], Jeroen reported
> a massive regression in elliptic curve computations. The regression was
> introduced in the transition from sage-4.7.2.alpha2 to sage-4.7.2.alpha3.
>
> It seems that #9138 is responsible, at least for a big part of the
> regression. With unpatched sage-4.7.2.alpha2, we find
> {{{
> sage: E = J0(46).endomorphism_ring()
> sage: %time g = E.gens()
> CPU times: user 5.54 s, sys: 0.15 s, total: 5.69 s
> Wall time: 5.81 s
> }}}
> Adding #9138 and its dependency, we obtain
> {{{
> sage: E = J0(46).endomorphism_ring()
> sage: %time g = E.gens()
> CPU times: user 8.72 s, sys: 0.18 s, total: 8.89 s
> Wall time: 8.92 s
> }}}
>
> It turns out that much time is wasted for calls to
> `sage.categories.Category.join` and to
> `sage.categories.Category.hom_category`.
>
> When caching these two methods, one can reduce the speed difference to
> something like that (sage-4.7.2.alpha3 plus #11115 plus an experimental
> patch for the caching):
> {{{
> sage: E = J0(46).endomorphism_ring()
> sage: %time g = E.gens()
> CPU times: user 6.82 s, sys: 0.16 s, total: 6.98 s
> Wall time: 7.40 s
> }}}
> However, that's still far from good. After caching join and hom_category,
> there is still too much time spent (according to %prun) for the
> initialisation of matrix spaces.
>
> Apply:
>
> * [attachment:trac11900_no_categories_for_matrices.patch]
> * [attachment:trac11900_category_speedup.patch]
> * [attachment:trac11900_further_tweaks.patch]
> * [attachment:trac_11900-category_singleton-sk.patch]
New description:
At [http://groups.google.com/group/sage-
devel/browse_thread/thread/d885434ba9c22d66 sage-devel], Jeroen reported a
massive regression in elliptic curve computations. The regression was
introduced in the transition from sage-4.7.2.alpha2 to sage-4.7.2.alpha3.
It seems that #9138 is responsible, at least for a big part of the
regression. With unpatched sage-4.7.2.alpha2, we find
{{{
sage: E = J0(46).endomorphism_ring()
sage: %time g = E.gens()
CPU times: user 5.54 s, sys: 0.15 s, total: 5.69 s
Wall time: 5.81 s
}}}
Adding #9138 and its dependency, we obtain
{{{
sage: E = J0(46).endomorphism_ring()
sage: %time g = E.gens()
CPU times: user 8.72 s, sys: 0.18 s, total: 8.89 s
Wall time: 8.92 s
}}}
It turns out that much time is wasted for calls to
`sage.categories.Category.join` and to
`sage.categories.Category.hom_category`.
When caching these two methods, one can reduce the speed difference to
something like that (sage-4.7.2.alpha3 plus #11115 plus an experimental
patch for the caching):
{{{
sage: E = J0(46).endomorphism_ring()
sage: %time g = E.gens()
CPU times: user 6.82 s, sys: 0.16 s, total: 6.98 s
Wall time: 7.40 s
}}}
However, that's still far from good. After caching join and hom_category,
there is still too much time spent (according to %prun) for the
initialisation of matrix spaces.
Apply [attachment:trac11900_category_speedup_combined.patch]
--
Comment(by SimonKing):
I attached a file that combines the previous patches.
In addition, it uses `... in _Rings` with `_Rings=Rings()` in many cases.
However, I am now running doctests, and I get at least one error because
of that. Apparently some ring is initialised as ring, but should better be
a commutative ring.
Also I didn't check that all changes are documented.
So, still "needs work". But perhaps you like to have a look already...
Apply trac11900_category_speedup_combined.patch
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/11900#comment:136>
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