[Numpy-discussion] 1.8.0rc1

[Sebastian Berg]

On Wed, 2013-10-02 at 12:54 +0200, Sebastian Berg wrote:
> On Wed, 2013-10-02 at 10:04 +0100, Nathaniel Smith wrote:
> > This is a complicated issue to describe but i think the bottom line is
> > that the test is just wonky here. the behaviour it's checking for is:
> > wrong in old numpy, but we do it anyway (bug)
> > wrong in current numpy without RELAXED_STRIDES, and we get it right
> > (I.e. don't do it, fixed bug)
> > correct in current numpy with RELAXED_STRIDES (and I think the test
> > will pass if you build 1.8 this way?) (fixed bug again, since the
> > definition of "correct" flipped)
> > correct in future numpys
> > 

OK, I had a look. And it is the 1-dimensional size-1 special case that
was always "relaxed", but is not anymore. If anyone thinks this is a
problem, we could re-add the special case (rethinking it, it is almost
impossible to hurt, since the array has only one element). Otherwise, I
think the test should check if numpy was compiled with relaxed strides,
for more extensive tests this is necessary anyway.

- Sebastian


> Sounds about right, but I did not yet look at the test exactly. The old
> numpy had some corner cases where the *not* relaxed strides were not
> enforced. I could imagine that the test was written to accommodate the
> relaxed strides, but runs through fine with the old behaviour, too.
> 
> That said, if this is the case, this must be something like a size 1
> array corner case, so I would agree with Nathaniel, that probably the
> test should just see whether relaxed strides is active or not and change
> behaviour accordingly.
> 
> If this has to do with the Buffer protocol change we have to have a
> closer look if it might be breaking code out there. (even if the buffer
> protocol change is correct and this should be fixed on cythons end in
> that case)
> 
> - Sebastian
> 
> 
> > (@seberg, does that look right?)
> > 
> > I guess maybe we could go back and make sure it stays broken in 1.8,
> > but it's probably not worth the trouble because this is such a corner
> > case. Nothing real is going to break because of this AFAICT.
> > 
> > -n
> > 
> > On 2 Oct 2013 08:31, "Christoph Gohlke" <cgohlke at uci.edu> wrote:
> >         On 9/30/2013 8:17 AM, Charles R Harris wrote:
> >                 Hi All,
> >                 
> >                 NumPy 1.8.0rc1 is up now on sourceforge
> >                 <http://sourceforge.net/projects/numpy/files/NumPy/1.8.0rc1/> .The
> >                 binary builds are included except for Python 3.3 on
> >                 windows, which will
> >                 arrive later. Many thanks to Ralf for the binaries,
> >                 and to those who
> >                 found and fixed the bugs in the last beta. Any
> >                 remaining bugs are all my
> >                 fault ;) I hope this will be the last release before
> >                 final, so please
> >                 test it thoroughly.
> >                 
> >                 Chuck
> >                 
> >         
> >         One more: Cython-0.19.1 fails relaxed_strides.test_one_sized
> >         with "ValueError: ndarray is not C-contiguous". Tested on
> >         numpy-MKL-1.8.0rc1-win-amd64-py2.7 and msvc9.
> >         
> >         https://github.com/cython/cython/blob/0.19.x/tests/memoryview/relaxed_strides.pyx#L29
> >         
> >         The relevant test output is attached.
> >         
> >         Christoph
> >         
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