On Thu, Nov 30, 2017 at 11:43 AM, Ralf Gommers <ralf.gommers@gmail.com> wrote:

On Fri, Dec 1, 2017 at 7:17 AM, Matthew Rocklin <mrocklin@gmail.com> wrote:

How would the community handle the scipy.sparse matrix subclasses?  These are still in common use.

They're not going anywhere for quite a while (until the sparse ndarrays materialize at least). Hence np.matrix needs to be moved, not deleted. We discussed this earlier this year: https://mail.python.org/pipermail/numpy-discussion/2017-January/076332.html

Somewhat related: https://github.com/scipy/scipy/issues/8162

On Thu, Nov 30, 2017 at 1:13 PM, <josef.pktd@gmail.com> wrote:

On Thu, Nov 30, 2017 at 9:23 AM, Marten van Kerkwijk <m.h.vankerkwijk@gmail.com> wrote:

Hi All,

I wondered if the move to python3-only starting with numpy 1.17 would
be a good reason to act on what we all seem to agree: that the matrix
class was a bad idea, with its overriding of multiplication and lack
of support for stacks of matrices.

I'd suggest any release in the next couple of years is fine,but the one where we drop Python 2 support is probably the worst choice. That's one of the few things the core Python devs got 100% right with the Python 3 move: advocate that in the 2->3 transition packages would not make any API changes in order to make porting the least painful.

Ralf

Agree, we don't want to pile in too many changes at once. I think the big sticking point is the sparse matrices in SciPy, even issuing a DeprecationWarning could be problematic as long as there are sparse matrices. May I suggest that we put together an NEP for the NumPy side of things? Ralf, does SciPy have a mechanism for proposing such changes?