On Tue, Mar 29, 2011 at 12:07:15PM -0700, Simon King wrote:
> Tickets #9944 and #9138 provide some nice features, but slow things
> down. It seems to me that the reason of the performance loss is that
> the patches from these tickets make the method resolution order of
> polynomial rings much longer - in some cases the length doubles (15
> versus 39 steps until <type 'object'> is reached).
>
> As much as I understand: If the mro is longer than Python needs more
> time to look up a method that is defined for a very basic class (such
> as sage.structure.category_object.CategoryObject or
> sage.structure.parent.Parent).
Note: for good or bad, the Cython classes come before categories in
the mro:
sage: sage: C = CombinatorialFreeModule(ZZ, ZZ)
sage: C.__class__.mro()
[<class 'sage.combinat.free_module.CombinatorialFreeModule_with_category'>,
<class 'sage.combinat.free_module.CombinatorialFreeModule'>,
<class 'sage.structure.unique_representation.UniqueRepresentation'>,
<type 'sage.modules.module.Module'>,
<type 'sage.structure.parent.Parent'>,
<type 'sage.structure.category_object.CategoryObject'>,
<type 'sage.structure.sage_object.SageObject'>,
<class 'sage.categories.modules_with_basis.ModulesWithBasis.parent_class'>,
... <type 'object'>]
So the number of classes to walk through to find base_ring only
increases by 1 (due to the _with_category).
Cheers,
Nicolas
--
Nicolas M. Thiéry "Isil" <[email protected]>
http://Nicolas.Thiery.name/
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