[SciPy-dev] FAIL: test_yn_zeros, test_ynp_zeros, Negative-order Bessels

[Pauli Virtanen]

Mon, 26 Jan 2009 11:27:30 +0100, Nils Wagner wrote:
> ======================================================================
> FAIL: test_yv_cephes_vs_amos (test_basic.TestBessel)
> ----------------------------------------------------------------------
[clip]
> Traceback (most recent call last):
>    File
> "/data/home/nwagner/local/lib/python2.5/site-packages/scipy/special/
tests/test_basic.py",
> line 1650, in test_yv_cephes_vs_amos
>      self.check_cephes_vs_amos(yv, yn, rtol=1e-11,
> atol=1e-305)
>    File
> "/data/home/nwagner/local/lib/python2.5/site-packages/scipy/special/
tests/test_basic.py",
> line 1640, in check_cephes_vs_amos
>      assert c2.imag != 0, (v, z)
> AssertionError: (301, 1.0)

Appears to be a bug in cephes/yn on 64-bit systems:

>>> import scipy
>>> import scipy.special as sc
>>> scipy.__version__
'0.7.0.dev5268'
>>> sc.yn(301,1)
nan

whereas on a 32-bit system it gives the correct answer:

>>> sc.yn(301,1)
-inf