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

[Matthew Brett]

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?

Cheers,

Matthew