#17663: Clean up sparse matrices
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Reporter: | Owner:
vdelecroix | Status: needs_review
Type: | Milestone: sage-6.5
enhancement | Resolution:
Priority: major | Merged in:
Component: | Reviewers: Martin von Gagern
linear algebra | Work issues:
Keywords: | Commit:
Authors: | d292e6ff17ea1815e5b24267a6d0140ea5598add
Vincent Delecroix | Stopgaps:
Report Upstream: N/A |
Branch: |
public/17663 |
Dependencies: |
#17658 |
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Comment (by gagern):
Replying to [comment:19 vdelecroix]:
> It depends on the school! "my_var is None" is a simple address lookup
while "not my_var" implies a function call. So "my_var is None" is very
fast compared to "not my_var".
Valid point, so I won't object to leave the code as it is. Might even
adapt that style.
> > * `_cmp_backward` might use `if i != j: return i - j` in the first
case as well. Not sure whether that makes much of a difference.
>
> Actually this is what I tried. But if you do that, you end up with some
warning claiming that the comparison routine returns something different
from 0,1,-1!
Can't reproduce such a warning. Who is complaining when? Why no warning
for the other pair component? I wonder whether one would want to put some
bigger numbers in the test case, in order to make sure that steps with
absolute value more than one are always involved in some comparison. But
even then I don't see this warning you mention.
My question about the `The input must be scalar or a dictionary` exception
being dead code (from comment:23) still stands. I just pushed a commit for
that. If you have no objections to it, feel free to mark this as positive
review, since I'm happy with your changes.
--
Ticket URL: <http://trac.sagemath.org/ticket/17663#comment:31>
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