[Numpy-discussion] Questions about fixes for 1.9.0rc2

[Nathaniel Smith]

On Fri, Jul 4, 2014 at 10:31 PM, Charles R Harris
<charlesr.harris at gmail.com> wrote:
>
> On Fri, Jul 4, 2014 at 3:15 PM, Nathaniel Smith <njs at pobox.com> wrote:
>>
>> On Fri, Jul 4, 2014 at 9:48 PM, Charles R Harris
>> <charlesr.harris at gmail.com> wrote:
>> >
>> > On Fri, Jul 4, 2014 at 2:41 PM, Nathaniel Smith <njs at pobox.com> wrote:
>> >>
>> >> On Fri, Jul 4, 2014 at 9:33 PM, Charles R Harris
>> >> <charlesr.harris at gmail.com> wrote:
>> >> >
>> >> > On Fri, Jul 4, 2014 at 2:09 PM, Nathaniel Smith <njs at pobox.com>
>> >> > wrote:
>> >> >>
>> >> >> On Fri, Jul 4, 2014 at 9:02 PM, Ralf Gommers
>> >> >> <ralf.gommers at gmail.com>
>> >> >> wrote:
>> >> >> >
>> >> >> > On Fri, Jul 4, 2014 at 10:00 PM, Charles R Harris
>> >> >> > <charlesr.harris at gmail.com> wrote:
>> >> >> >>
>> >> >> >> On Fri, Jul 4, 2014 at 1:42 PM, Charles R Harris
>> >> >> >> <charlesr.harris at gmail.com> wrote:
>> >> >> >>>
>> >> >> >>> Sebastian Seberg has fixed one class of test failures due to the
>> >> >> >>> indexing
>> >> >> >>> changes in numpy 1.9.0b1.  There are some remaining errors, and
>> >> >> >>> in
>> >> >> >>> the
>> >> >> >>> case
>> >> >> >>> of the Matplotlib failures, they look to me to be Matplotlib
>> >> >> >>> bugs.
>> >> >> >>> The
>> >> >> >>> 2-d
>> >> >> >>> arrays that cause the error are returned by the overloaded
>> >> >> >>> _interpolate_single_key function in CubicTriInterpolator that is
>> >> >> >>> documented
>> >> >> >>> in the base class to return a 1-d array, whereas the actual
>> >> >> >>> dimensions
>> >> >> >>> are
>> >> >> >>> of the form (n, 1). The question is, what is the best work
>> >> >> >>> around
>> >> >> >>> here
>> >> >> >>> for
>> >> >> >>> these sorts errors? Can we afford to break Matplotlib and other
>> >> >> >>> packages on
>> >> >> >>> account of a bug that was previously accepted by Numpy?
>> >> >> >
>> >> >> >
>> >> >> > It depends how bad the break is, but in principle I'd say that
>> >> >> > breaking
>> >> >> > Matplotlib is not OK.
>> >> >>
>> >> >> I agree. If it's easy to hack around it and issue a warning for now,
>> >> >> and doesn't have other negative consequences, then IMO we should
>> >> >> give
>> >> >> matplotlib a release or so worth of grace period to fix things.
>> >> >
>> >> >
>> >> > Here is another example, from skimage.
>> >> >
>> >> >
>> >> > ======================================================================
>> >> > ERROR: test_join.test_relabel_sequential_offset1
>> >> >
>> >> > ----------------------------------------------------------------------
>> >> > Traceback (most recent call last):
>> >> >   File "X:\Python27-x64\lib\site-packages\nose\case.py", line 197, in
>> >> > runTest
>> >> >     self.test(*self.arg)
>> >> >   File
>> >> >
>> >> >
>> >> > "X:\Python27-x64\lib\site-packages\skimage\segmentation\tests\test_join.py",
>> >> > line 30, in test_relabel_sequential_offset1
>> >> >     ar_relab, fw, inv = relabel_sequential(ar)
>> >> >   File
>> >> > "X:\Python27-x64\lib\site-packages\skimage\segmentation\_join.py",
>> >> > line 127, in relabel_sequential
>> >> >     forward_map[labels0] = np.arange(offset, offset + len(labels0) +
>> >> > 1)
>> >> > ValueError: shape mismatch: value array of shape (6,) could not be
>> >> > broadcast
>> >> > to indexing result of shape (5,)
>> >> >
>> >> > Which is pretty clearly a coding error. Unfortunately, the error is
>> >> > in
>> >> > the
>> >> > package rather than the test.
>> >> >
>> >> > The only easy way to fix all of these sorts of things is to revert
>> >> > the
>> >> > indexing changes, and I'm loathe to do that. Grrr...
>> >>
>> >> Ugh, that's pretty bad :-/. Do you really think we can't use a
>> >> band-aid over the new indexing code, though?
>> >
>> >
>> > Yeah, we can. But Sebastian doesn't have time and I'm unfamiliar with
>> > the
>> > code, so it may take a while...
>>
>> Fair enough!
>>
>> I guess that if what are (arguably) bugs in matplotlib and
>> scikit-image are holding up the numpy release, then it's worth CC'ing
>> their mailing lists in case someone feels like volunteering to fix
>> it... ;-).
>
> I can do that ;) Doesn't help with the release though unless we want to
> document the errors in the release notes and tell folks to wait on the next
> release of the packages.

Oh, I meant, in case they want to fix numpy so that their packages
don't break :-).

-- 
Nathaniel J. Smith
Postdoctoral researcher - Informatics - University of Edinburgh
http://vorpus.org