#11900: Serious regression caused by #9138
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Reporter: SimonKing | Owner: tbd
Type: defect | Status: needs_work
Priority: major | Milestone: sage-4.7.3
Component: performance | Keywords: categories regression
Work_issues: fix doctests | Upstream: N/A
Reviewer: | Author: Simon King
Merged: | Dependencies: #9138 #11911
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Comment(by nthiery):
Hi Simon,
Replying to [comment:50 SimonKing]:
> and also it is faster to do `base_ring.is_ring()` if `is_ring` is a
parent method.
I thought that you had optimized the `in` containment to make it as
fast as a method call? Besides, as far as I remember from previous
discussions, we had agreed on the following:
- X in Fields() would return whether X is already known to be a
field.
- X.is_field() would return whether X *is* a field, possibly
launching a costly computation if needed, and possibly updating the
category afterward
Finally, to do dispatching in category code, the preferred idiom would
be X in Fields(). Roughly speaking, operations on an element depend on
its declared parent, operations on a parent depend on its declared
category.
Cheers,
Nicolas
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/11900#comment:52>
Sage <http://www.sagemath.org>
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