[Numpy-discussion] Questions about fixes for 1.9.0rc2

[Charles R Harris]

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...

Chuck
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