#12149: float('nan')>1 crashes Sage.
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Reporter: was | Owner: AlexGhitza
Type: defect | Status: needs_review
Priority: critical | Milestone: sage-4.8
Component: basic arithmetic | Keywords:
Work_issues: | Upstream: N/A
Reviewer: | Author: William Stein
Merged: | Dependencies:
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Comment(by was):
Replying to [comment:13 SimonKing]:
> Replying to [comment:12 jdemeyer]:
> > So it's a minor issue about specifications, not a big deal. Doing
something against the Python specifications isn't an issue if you're
trying to avoid complete crashes of Sage.
>
> And what does that mean? Use William's patch, or a try-sig_on-sig_off-
except patch?
jdemeyer is remarking that as a general rule we should wrap code that
might send SIGFPE signals in sig_on/sig_off. With the patch I've
attached, I believe there is no possible way that the relevant code will
ever send a SIGFPE signal. For such code, it would make no sense at all
to use sig_on/sig_off.
I think SimonKing's timings above are bogus, because you say that you use
"a = 1, b = 2, c = 1", which are all integers, yet the relevant code path
will only be hit if one operand is a Sage integer and the other is a
Python float. You need to test with a Sage integer, a Python float that
isn't float('nan'), and also with one that is. Probably your differences
in timings are meaningless noise. I wish timeout output both a mean and
standard deviation, so one could tell whether comparisons are meaningful.
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/12149#comment:14>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
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