#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 SimonKing):
Replying to [comment:10 jdemeyer]:
> Replying to [comment:7 SimonKing]:
> > It is wrong to use sig_on/sig_off in comparison code without "try-
except".
> Why is that?
Because comparison in Python must not result in an error, if I remember
correctly the Python specifications.
Here are timings, using `a = 1, b = 2, c = 1".
Vanilla sage-4.8.alpha3:
{{{
sage: timeit("a==b",number=10^5)
100000 loops, best of 3: 271 ns per loop
sage: timeit("a==c",number=10^5)
100000 loops, best of 3: 268 ns per loop
sage: timeit("a==x",number=10^5)
100000 loops, best of 3: 13.8 µs per loop
}}}
William's patch:
{{{
sage: timeit("a==b",number=10^5)
100000 loops, best of 3: 260 ns per loop
sage: timeit("a==c",number=10^5)
100000 loops, best of 3: 266 ns per loop
sage: timeit("a==x",number=10^5)
100000 loops, best of 3: 14.7 µs per loop
}}}
try-sigon-sigoff-except:
{{{
sage: timeit("a==b",number=10^5)
100000 loops, best of 3: 272 ns per loop
sage: timeit("a==c",number=10^5)
100000 loops, best of 3: 266 ns per loop
sage: timeit("a==x",number=10^5)
100000 loops, best of 3: 13.6 µs per loop
}}}
So, it is not really that much of a difference.
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/12149#comment:11>
Sage <http://www.sagemath.org>
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