[SciPy-dev] NumPy f2py GSOC project
Dag Sverre Seljebotn
Thu Mar 26 17:47:38 CDT 2009
Charles R Harris wrote:
> On Thu, Mar 26, 2009 at 2:44 PM, Kurt Smith <firstname.lastname@example.org
> <mailto:email@example.com>> wrote:
> 2009/3/26 ross smith <firstname.lastname@example.org <mailto:email@example.com>>:
> > When I looked at that one, It seemed to me like they are trying
> to use it
> > to bind fortran and C together with only a thin, fairly
> transparent python
> > layer in the middle.
> Actually, it's more like binding Fortran to Python/Cython and
> enhancing the ability to pass numpy arrays and python buffer objects
> to external fortran code. The "f2c" capability (with fortran 2003 ISO
> C bindings) is just gravy ;-) The "python layer" will likely have to
> do a good bit of work to make the passing of arrays seamless to the
> user and minimize the copying of arrays.
> I'm a bit confused as to how these two projects relate each other.
> Should they be coordinated or can they stand separately? What would be
> the upshot? If f2py is updated, then presumably it could act as a drop
> in replacement for the current f2py. Would the cython project have that
> same effect?
- Only uses the parser from f2py, but may provide some
improvements/patches for that part. There's a good chance 3rd gen f2py
will be chosen in which case there is probably no overlap codewise (if
Ross' project is for 2nd gen f2py).
- A drop-in replacement for f2py is not a goal. It could be for
projects where no changes are made to generated .pyf files, but will not
become one for custom-written .pyf files
- Will facilitate wrapping Fortran modules using Cython in the same
way one uses Cython for C (i.e. if non-trivial wrapping is needed one
writes Cython code rather than a modify a .pyf file).
If Ross' project involves work on the same parser (likely this means the
3rd gen f2py) then some coordination would be in order in the parser;
this could rather trivially be resolved. Otherwise there doesn't seem to
be any overlap.
As far as I can gather, that is. But I must admit that I don't really
understand Ross' project. What part will be ported to Cython? As I
understand it, a) f2py itself is entirely written in Python already, b)
it generates a C module much like Cython does, which must currently be
kept Py2 because of the NumPy dependency.
If the plan is to switch to a Cython backend, so that f2py starts
*generating* Cython code, then there's somewhat more overlap in goals.
(But that would break existing .pyf files as they can contain free-form
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