[SciPy-Dev] [fwrap-users] Work on fwrap and SciPy

[Kurt Smith]

On Wed, Nov 3, 2010 at 5:26 AM, Dag Sverre Seljebotn
<dagss at student.matnat.uio.no> wrote:
> This is just a quick note to inform people that I am currently working with
> Enthought to bring SciPy to the .NET platform. In particular, I will work on
> the Fortran parts of SciPy.
>
> The primary strategy will be to improve fwrap enough to make it usable for
> SciPy, and then move SciPy over to fwrap instead of f2py. The point here is
> that Carl Witty is already working on a .NET backend for Cython, and since
> fwrap generates Cython code we get the .NET port that way.

This is great news.  Thanks for doing this, and to Enthought for
providing support.  I think all parties will benefit :-)

>
> All work is done in Enthought's "refactor" branches for now [1]. The
> intention is certainly to merge back to main eventually, but questions of
> how or when or whether will have to wait; getting things up and running on
> .NET has priority.
>

Sure.  The fact that the .NET-specific stuff is in Cython should make
merging fwrap much easier than it otherwise would be.  I'm interested
in keeping fwrap-main synced up with fwrap-.NET, so that they won't
diverge too much.  Your thoughts on this are welcome.

At any rate, whatever improvements I make to fwrap in the coming
months will likely be orthogonal to callbacks.  The code could use
some refactoring, to use the visitor pattern consistently throughout.

> Some details:
>
>  a) The most important missing feature in fwrap is callbacks. I'm sure there
> are other things I'll have to implement as well.
>

There are differences between callbacks in f77 and callbacks in F90,
using modern (Fortran 2003) features.  So figuring out whether g77
support is a requirement would be good to know before attacking this
problem.  F90 callbacks (using the 2003 features) are much stricter,
and last time I looked not all compilers support all features that
would be useful for callback support.

>  b) The main strategy is to first move (our own branch of) SciPy over to
> fwrap and have that work on CPython, and then move to compiling things on
> .NET
>
>  c) fwrap does not support g77, only Fortran 90 compilers like
> gfortran/ifort etc. For the purposes of the .NET port this is likely to be
> good enough. Before a merge with the main CPython branch one must perhaps
> look into implementing g77 support in fwrap. I know that David C. at least
> earlier stated that g77 support is not going away anytime soon. Feedback on
> this welcome.
>

I'm interested to hear what DC has to say...

> Dag Sverre
>
> [1]
> http://github.com/teoliphant/numpy-refactor
> http://github.com/jasonmccampbell/scipy-refactor