#11589: faster zero matrix creation
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Reporter: malb | Owner: jason, was
Type: enhancement | Status: new
Priority: major | Milestone: sage-4.7.2
Component: linear algebra | Keywords:
Work_issues: | Upstream: N/A
Reviewer: | Author: Martin Albrecht, Simon King
Merged: | Dependencies:
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Comment(by malb):
Replying to [comment:2 SimonKing]:
> I don't like that the timings became a little slower for small matrices.
We should try to find out why that happens.
We'll also have to do more careful timings to establish there really was a
regression. I'm not 100% sure it's not a fluke.
> I think we should use calloc ''only'' when the argument `entries` is not
a list. Namely, ''if'' it is a list then the matrix will be initialised by
direct assignments anyway. Hence, in that case there is no need to
initialise with calloc.
Good point.
> Did you carefully determine the threshold for which calloc becomes
faster than copying? Or is "nrows, ncols > 100" just a guess?
An educated guess, i.e. I did look at some timings but it's not carefully
tuned (and probably machine dependent).
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/11589#comment:3>
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