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To: gentoo-science@g.o
From: Darren Dale <dd55@...>
Subject: Re: question about signbit
Date: Fri, 28 Oct 2005 12:00:05 -0400
On Friday 28 October 2005 11:40 am, Marco Matthies wrote:
> Darren Dale wrote:
> > signbit(-1): -2147483648
> > isnan(0.0/0): 1
> > isinf(1.0/0): 1
>
> As other people have already noted, signbit from math.h is behaving as
> it should.
>
> > Do you know why signbit doesn't yield 1? I wonder if this might be the
> > source of the problem in Scipy.
>
> I actually had a look at scipy today, and it uses its own signbit
> routine -- so looking at what signbit from math.h does is totally
> irrelevant. The scipy signbit implementation does say it returns 0 or 1.

Actually, SciPy's signbit is only used if math.h does not supply it. On my 
system, the math.h version of signbit is used. I talked with the lead scipy 
developer this morning, and based on the fact that signbit was returning a 
nonzero result rather than 1, he made a modification to scipy's code and we 
got the problem solved. Thank you everyone for your help. All of Scipy's 
tests are now successful on my arch, I think they will have a test release 
coming in the not-too-distant future.

Darren
-- 
gentoo-science@g.o mailing list


References:
question about signbit
-- Darren Dale
Re: question about signbit
-- Darren Dale
Re: question about signbit
-- Marco Matthies
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