[Numpy-discussion] ANN: NumPy 1.5.0 beta 2

[Christoph Gohlke]

On 8/17/2010 1:02 PM, Charles R Harris wrote:
>
>
> On Tue, Aug 17, 2010 at 1:38 PM, Christoph Gohlke <cgohlke at uci.edu
> <mailto:cgohlke at uci.edu>> wrote:
>
>
>
>     On 8/17/2010 8:23 AM, Ralf Gommers wrote:
>
>         I am pleased to announce the availability of the second beta of
>         NumPy
>         1.5.0. This will be the first NumPy release to include support for
>         Python 3, as well as for Python 2.7.
>
>         Please try this beta and report any problems on the NumPy
>         mailing list.
>         Especially with Python 3 testing will be very useful. On Linux
>         and OS X
>         building from source should be straightforward, for Windows a binary
>         installer is provided. There is one important known issue on Windows
>         left, in fromfile and tofile (ticket 1583).
>
>         Binaries, sources and release notes can be found at
>         https://sourceforge.net/projects/numpy/files/
>         <https://sourceforge.net/projects/numpy/files/>
>
>         Enjoy,
>         Ralf
>
>
>     NumPy 1.5.0 beta 2 built with msvc9/mkl for Python 2.7 and 3.1 (32
>     and 64 bit) still reports many (> 200) warnings and three known test
>     failures/errors. Nothing serious, but it would be nice to clean up
>     before the final release.
>
>     The warnings are of the type "Warning: invalid value encountered in"
>     for the functions reduce, fmax, fmin, logaddexp, maximum, greater,
>     less_equal, greater_equal, absolute, and others. I do not see any of
>     these warnings in the msvc9 builds of numpy 1.4.1.
>
>
> The warnings were accidentally turned off for earlier versions of Numpy.
> I expect these warnings are related to nans and probably due to problems
> with isnan or some such. Can you take a closer look? The fmax function
> should be easy to check out.
>
> <sniip>
>
> Chuck
>


Thanks for the hint. Warnings are issued in the test_umath test_*nan* 
functions. The problem can be condensed to this statement:

>>> numpy.array([numpy.nan]) > 0
Warning: invalid value encountered in greater
array([False], dtype=bool)


When using msvc, ordered comparisons involving NaN raise an exception 
[1], i.e. set the 'invalid' x87 status bit, which leads to the warning 
being printed. I don't know if this violates IEEE 754 or C99 standards 
but it does not happen with the gcc builds. Maybe 
seterr(invalid='ignore') could be added to the test_*nan* functions?

[1] http://msdn.microsoft.com/en-us/library/e7s85ffb%28v=VS.90%29.aspx

--
Christoph