#12121: floor/ceil can be very slow at integral values
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Reporter: dsm | Owner: AlexGhitza
Type: | Status: needs_work
defect |
Priority: major | Milestone: sage-7.2
Component: basic | Resolution:
arithmetic |
Keywords: | Merged in:
Authors: | Reviewers: Marc Mezzarobba
Vincent Delecroix |
Report Upstream: N/A | Work issues:
Branch: | Commit:
public/12121 | 9bd70406da71c6e1083fc25cd57435788689018e
Dependencies: | Stopgaps:
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Comment (by vdelecroix):
Replying to [comment:49 mmezzarobba]:
> > On a related note, I noticed that for `round` you need to test
equality with elements of `ZZ + 1/2`.
>
> Couldn't you just compute ceil(x-1/2)?
{{{
sage: x = 0.5
sage: print x.round() == (x-0.5).ceil()
False
}}}
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Ticket URL: <https://trac.sagemath.org/ticket/12121#comment:54>
Sage <http://www.sagemath.org>
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