[SciPy-Dev] Cython as build dependency, file/dll size and current issues

[Ralf Gommers]

On Thu, Jul 5, 2012 at 8:31 PM, Matthew Brett <matthew.brett at gmail.com>wrote:

> Hi,
>
> On Thu, Jul 5, 2012 at 11:25 AM, Ralf Gommers
> <ralf.gommers at googlemail.com> wrote:
> > Hi all,
> >
> > On https://github.com/scipy/scipy/pull/261 the problem with large size
> of
> > generated C files from Cython came up again, and Matthew suggested to add
> > Cython as a build time dependency. He also pointed out that this was
> > discussed before, with most people being in favor:
> > http://mail.scipy.org/pipermail/scipy-dev/2009-November/013272.html
> > http://mail.scipy.org/pipermail/scipy-dev/2009-November/013308.html
> > We discussed the same issue on https://github.com/scipy/scipy/pull/211
> > recently, and also the size of the binary.
> >
> > This is probably also the right moment to point out other recent Cython
> > issues we've had:
> > 1. A memoryview issue with Python 2.4, either a Cython or Numpy bug:
> > https://github.com/numpy/numpy/pull/307
> > 2. We had to manually patch the generated C files when using Cython
> 0.16, to
> > make them work with MinGW: http://projects.scipy.org/scipy/ticket/1673
> > 3. According to Ray, there's also an indexing bug in Cython 0.16 which
> > requires to use 0.17-dev for https://github.com/scipy/scipy/pull/261
> >
> > I think it's clear that PR's like #261 above (Ray's ndimage.label
> rewrite)
> > are in principle a good thing: faster and more general code which is
> easier
> > to maintain. Now the question is what to do though. Here's some options
> that
> > I see:
> >
> > a) Keep things as is for now. Accept large file/binary sizes. Manually
> patch
> > the generated C if necessary.
> > b) Keep things as is for now. Either go back to Cython 0.15, or bump
> > required numpy version to latest dev version to not have to manually
> patch
> > the generated C files.
> > c) Keep things as they are now, without accepting too large file/binary
> > sizes. To be defined what too large. Means we can't get the full
> benefits of
> > fused types for example.
> > d) Move to Cython as a build dependency. Write down the required versions
> > and incompatibilities in the docs.
> > e) Include a Cython version in the scipy git repo, patch it to solve the
> > above issues 2 and 3 (and any other ones that come along).
> > f) Some combination of the above.
> > g) Any other options?
>
> Am I right in thinking that Cython 0.17dev will generate usable C
> files without patching?
>

Yes.
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