#10963: More functorial constructions
-------------------------------------+-------------------------------------
Reporter: nthiery | Owner: stumpc5
Type: enhancement | Status: needs_info
Priority: major | Milestone: sage-6.2
Component: categories | Resolution:
Keywords: days54 | Merged in:
Authors: Nicolas M. Thiéry | Reviewers: Simon King, Frédéric
Report Upstream: N/A | Chapoton
Branch: | Work issues:
public/ticket/10963-doc- | Commit:
distributive | 1cdc128a85851dd007b3b77ec53a4853a10e1de4
Dependencies: #11224, #8327, | Stopgaps:
#10193, #12895, #14516, #14722, |
#13589, #14471, #15069, #15094, |
#11688, #13394, #15150, #15506, |
#15757, #15759 |
-------------------------------------+-------------------------------------
Comment (by nbruin):
There are some performance and leaking issues with the proposed code here.
They have been mentioned before, but they got swamped in more theoretical
design discussions. Consider for instance without the patch:
{{{
sage: import gc
sage: from collections import Counter
sage: %time for n in [1..5000]: x=(matrix(Integers(n),2,2,1))
CPU times: user 5.25 s, sys: 0.02 s, total: 5.27 s
Wall time: 5.34 s
sage: gc.collect()
13714
sage: [c for c in Counter([type(a) for a in gc.get_objects()]).items() if
c[1] > 4000]
[(weakref, 5432),
(wrapper_descriptor, 4162),
(method_descriptor, 6241),
(function, 30547),
(list, 26843),
(tuple, 10281),
(dict, 9481)]
}}}
and with the patch:
{{{
sage: import gc
sage: from collections import Counter
sage: %time for n in [1..5000]: x=(matrix(Integers(n),2,2,1))
CPU times: user 12.8 s, sys: 109 ms, total: 13 s
Wall time: 13 s
sage: gc.collect()
1496
sage: [c for c in Counter([type(a) for a in gc.get_objects()]).items() if
c[1] > 4000]
[(sage.rings.finite_rings.integer_mod.Int_to_IntegerMod, 5001),
(sage.rings.finite_rings.integer_mod.IntegerMod_int, 138255),
(sage.rings.finite_rings.integer_mod.NativeIntStruct, 5001),
(sage.structure.coerce_dict.MonoDict, 20412),
(sage.rings.ideal.Ideal_pid, 5001),
(sage.categories.homset.Homset_with_category, 5040),
(cell, 73146),
(instancemethod, 10387),
(wrapper_descriptor, 4160),
(method_descriptor, 6395),
(sage.misc.cachefunc.CachedMethodCallerNoArgs, 40956),
(sage.misc.cachefunc.CachedMethodCaller, 30124),
(staticmethod, 36521),
(function, 64203),
(list, 107010),
(dict, 120792),
(builtin_function_or_method, 32639),
(tuple, 338430),
(weakref, 71075),
(sage.rings.finite_rings.integer_mod_ring.IntegerModRing_generic_with_category,
4331),
(sage.structure.dynamic_class.DynamicClasscallMetaclass, 35867),
(sage.structure.coerce_dict.TripleDictEraser, 10180),
(sage.structure.coerce_dict.MonoDictEraser, 20412),
(sage.structure.coerce_dict.TripleDict, 10180),
(weakref.KeyedRef, 86907),
(frozenset, 30790)]
}}}
As you can see, much slower execution and much leakier behaviour (even
without the patch this kind of stuff is very liable to leak but as you can
see, this patch makes it much worse)
--
Ticket URL: <http://trac.sagemath.org/ticket/10963#comment:571>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
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