numpy, overflow, inf, ieee, and rich comparison
Huaiyu Zhu
hzhu at yahoo.com
Tue Oct 10 03:46:03 EDT 2000
Well, maybe this is a 2.0 bug (or feature)?
On Mon, 9 Oct 2000 22:25:59 -0400, Tim Peters <tim_one at email.msn.com> wrote:
>
>While that's inherited from your libc.
...
>
>I haven't used Numeric, but I do guess you're simply hosed without resorting
>to C.
I thought so, BUT
$ /usr/bin/python
Python 1.5.2 (#1, Sep 17 1999, 20:15:36) [GCC egcs-2.91.66 19990314/Linux
(egcs- on linux-i386
Copyright 1991-1995 Stichting Mathematisch Centrum, Amsterdam
>>> from math import *
>>> exp(-745)
4.94065645841e-324
>>> exp(-746)
0.0
$ /usr/local/bin/python
Python 2.0b2 (#2, Oct 6 2000, 17:54:55)
[GCC egcs-2.91.66 19990314/Linux (egcs-1.1.2 release)] on linux2
Type "copyright", "credits" or "license" for more information.
>>> from math import *
>>> exp(-745)
4.9406564584124654e-324
>>> exp(-746)
Traceback (most recent call last):
File "<stdin>", line 1, in ?
OverflowError: math range error
This is on the same machine. Notice that GCC? Exactly the same version. So
what's going on here? I was wondering why I hadn't noticed this underflow
for such a long time ...
Maybe 2.0 fixes Window's bug wile introducing Linux bug? One thing I can
confirm is that Numeric behaves the same as math in this regard.
Huaiyu
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