[gentoo-science] question about signbit

[Darren Dale]

Hello,

A while back, SciPy was added to the portage tree. There will be a new version 
of SciPy soon, which will hopefully unify the Numeric/numarray split in the 
Python community.

I am trying to track down the source of a bug in the SciPy development branch 
which, so far, has only been reported on a Gentoo platform (mine). It 
involves the use of the libc math function "signbit". Here is a clip from the 
manpage:

       `signbit' is a generic macro which can work on all real floating-
       point types.  It returns a non-zero value if the value of  X  has
       its sign bit set.

On my system, SciPy's signbit function reports that the sign bit is not set 
for any number, positive or negative. Could someone here help me understand 
how to test the libc signbit function? I have to admit I have no experience 
with C programming.

Thanks,

Darren
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