[Numpy-discussion] test failure in numpy trunk

Charles R Harris charlesr.harris@gmail....
Tue Mar 24 14:47:21 CDT 2009


On Tue, Mar 24, 2009 at 1:12 PM, Pauli Virtanen <pav@iki.fi> wrote:

> Tue, 24 Mar 2009 13:15:21 -0400, Darren Dale wrote:
> > I just performed an svn update, deleted my old build/ and
> > site-packages/numpy*, reinstalled, and I see a new test failure on a 64
> > bit linux machine:
> >
> > ======================================================================
> > FAIL: test_umath.TestComplexFunctions.test_loss_of_precision_longcomplex
> > ----------------------------------------------------------------------
> [clip]
> >   "/usr/lib64/python2.6/site-packages/numpy/core/tests/test_umath.py",
> > line 497, in check
> >     'arctanh')
> > AssertionError: (135, 3.4039637354191726288e-09,
> > 3.9031278209478159624e-18, 'arctanh')
>
> I can reproduce this (on another 64-bit machine). This time around, it's
> the real function that is faulty:
>
> >>> x = np.longdouble(3e-9)
> >>> np.arctanh(x+0j).real - x
> 9.0876776281460559983e-27
> >>> np.arctanh(x).real - x
> 0.0
> >>> np.finfo(np.longdouble).eps * x
> 3.2526065174565132804e-28
>
> So, the system atanhl is ~ 30 relative eps away from the correct answer:
>

I see this also. The compiler is gcc version 4.3.0 20080428 (Red Hat
4.3.0-8) (GCC). Maybe we should ping the compiler folks? I could also open a
Fedora bug for this.

Chuck
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://mail.scipy.org/pipermail/numpy-discussion/attachments/20090324/80b8661c/attachment.html 


More information about the Numpy-discussion mailing list