Fri May 16 13:23:55 CDT 2008
On Fri, May 16, 2008 at 11:23 AM, Stuart Brorson <firstname.lastname@example.org> wrote:
> Hi guys,
> Just a quick note. I've been playing with NumPy again, looking at
> corner cases of function evaluation. I noticed this:
> In : numpy.sign(numpy.nan)
> Out: 0.0
> IMO, the output should be NaN, not zero.
> If you agree, then I'll be happy to file a bug in the NumPy tracker.
> Or if somebody feels like pointing me to the place where this is
> implemented, I can submit a patch. (I grepped through the source for
> "sign" to see if I could figure it out, but it occurs so frequently
> that it will take longer than 5 min to sort it all out.)
> Before I did anything, however, I thought I would solicit the opinions
> of other folks in the NumPy community about the proper behavior of
You're probably right. I would like to see what other systems do
before changing it, though.
The implementation is actually in a #define macro in
umathmodule.c.src. Look for _SIGN1 (and _SIGNC if you want to clean up
the complex versions, too).
"I have come to believe that the whole world is an enigma, a harmless
enigma that is made terrible by our own mad attempt to interpret it as
though it had an underlying truth."
-- Umberto Eco
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