[Numpy-discussion] RE: Python 2.2 seriously crippled for numerical computation?

Tim Peters tim.one at comcast.net
Fri Mar 8 21:18:01 CST 2002


I hope the bogus underflow problem is fixed in CVS Python now.  Since my
platform didn't have the problem (and still doesn't, of course), we won't
know for sure until people try it and report back.

Python used to link with -lieee, but somebody changed it for a reason
history may have lost.  See comments attached to Huaiyu Zhu's bug report for
more on that:

<http://sf.net/tracker/?func=detail&aid=525705&group_id=5470&atid=105470>

If someone on a box that had the problem can build current CVS Python with
and without -lieee (I'm told it defaults to "without" today, although that
appears to mixed up with whether or not __fpu_control is found outside of
libieee (search for "ieee" in configure.in)), please try the following in a
shell:

import math
x = 1e200
y = 1/x

math.pow(x, 2)  # expect OverflowError
math.pow(y, 2)  # expect 0.

pow(x, 2)       # expect OverflowError
pow(y, 2)       # expect 0.

x**2            # expect OverflowError
y**2            # expect 0.

If those all work as annotated on a box that had the problem, please report
the success *as a comment to the bug report* (link above).  If one or more
still fail, likewise please give box details and paste the failures into a
comment on the bug report.

Thanks!





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