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

Kurt Smith kwmsmith@gmail....
Wed Nov 3 16:00:14 CDT 2010

On Wed, Nov 3, 2010 at 5:26 AM, Dag Sverre Seljebotn
<dagss@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

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