[Numpy-discussion] Branch cuts, inf, nan, C99 compliance

Charles R Harris charlesr.harris@gmail....
Sun Jul 20 03:34:48 CDT 2008


On Sun, Jul 20, 2008 at 2:18 AM, Nils Wagner <nwagner@iam.uni-stuttgart.de>
wrote:

> On Sat, 19 Jul 2008 13:29:45 -0500
>  "Travis E. Oliphant" <oliphant@enthought.com> wrote:
> > Pauli Virtanen wrote:
> >> Hi all,
> >>
> >> Re: Ticket 854.
> >>
> >> I wrote tests for the branch cuts for all complex arc*
> >>functions
> >> in umathmodule. It turns out that all except arccosh
> >>were OK.
> >> The formula for arcsinh was written in a non-standard
> >>form with
> >> an unnecessary nc_neg, but this didn't affect the
> >>results.
> >> I also wrote tests for checking values of the functions
> >>at infs and nans.
> >>
> >
> > Thanks for looking into these.   These functions were
> >contributed by
> > Konrad Hinsen (IIRC) many years ago and I don't think
> >they've really
> > been reviewed since then.
> >
> > I'm all for using C99 when it is available and improving
> >these functions
> > with help from cmathmodule.  IIRC, the cmathmodule was
> >contributed by
> > Konrad originally also.
> >
> > So +1 on C99 standardization.
> >
> > -Travis
> >
>
> ======================================================================
> ERROR: test_umath.TestC99.test_catanh(<ufunc 'arctanh'>,
> (nan, nan), (nan, nan), '')
> ----------------------------------------------------------------------
> Traceback (most recent call last):
>   File
> "/usr/lib/python2.4/site-packages/nose-0.10.3-py2.4.egg/nose/case.py",
> line 182, in runTest
>     self.test(*self.arg)
>   File
> "/usr/lib/python2.4/site-packages/numpy/core/tests/test_umath.py",
> line 405, in _check
>     func(point)
> FloatingPointError: invalid value encountered in arctanh
>

<snip>

What architecture and OS?

Chuck
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