Re: [Starpu-devel] Fortran interface for StarPU

[Olivier Aumage <olivier.aumage@u-bordeaux.fr>]

Hi Alfredo,

I finally found some time to integrate this within StarPU, together with a 
few additional tweaks. 

I made some modifications to the proposal so as to make it possible to write 
native Fortran applications on top of StarPU, without having to write C code 
at all on the application side.

The currently supported Fortran StarPU functions are listed in 
STARPU/include/fstarpu_mod.f90

Some examples are available in STARPU/examples/native_fortran/. This 
directory also contains autonomous Makefiles to compile them from outside the 
StarPU build system.

Somes notes:
- fully native Fortran apps are supported with GFortran >= 4.9 and Intel 
Fortran >= 2016. I have not yet tested this with other compiler brands.
- the Fortran task implementation functions have to be declared in a module 
outside the main program source file, to avoid some link-time issue.
- the native Fortran interface is available in StarPU's SVN repository, in 
the trunk/ and in the starpu-1.2/ branches.

Please let me know if you have any suggestion, or need some additional key C 
StarPU functions in the Fortran interface.

Best regards,
--
Olivier

> Le 14 avr. 2016 à 10:03, Alfredo Buttari <alfredo.buttari@enseeiht.fr> a 
> écrit :
> 
> Dear StarPU developers,
> in order to port the qr_mumps solver on StarPU, I have written (and 
> re-written quite a few times) a module containing fortran interfaces for 
> StarPU methods as well as a few wrappers for those methods that cannot be 
> interfaced in a portable way. These wrappers are necessary mostly because 
> of the following issues:
> 
> 1) C variadic functions are not interoperable and (as far as I know) 
> there's no portable way to call them in a fortran code other than going 
> through a C wrapper.
> 
> 2) some StarPU structs (for example starpu_codelet) are not interoperable.
> 
> 3) the arguments of some functions are not of interoperable type. One weird 
> and very common case is the unsigned type which (for some obscure reason) 
> is not fortran interoperable. For arguments of this type we can use the 
> fortran integer type and it will just work although, on paper, this is not 
> portable.
> 
> In the attachment you can find the starpu_f_mod.f90 file containing a 
> number of interfaces and a starpu_f_wrappers.c containing C wrappers. The 
> package also contains a main program that shows how to use most of the 
> interfaced routines.
> 
> I discussed with Sam Thibault about the possibility to integrate this 
> interface in StarPU to make it available to the other concerned users. The 
> module is far from being complete and only contains a small fraction of all 
> the StarPU methods but if we agree on the approach and the syntax then it's 
> just a matter of coding the rest gradually, as needed.
> 
> 
> Ciao
> Alfredo
> 
> 
> 
> -- 
> -----------------------------------------
> Alfredo Buttari, PhD
> CNRS-IRIT
> 2 rue Camichel, 31071 Toulouse, France
> http://buttari.perso.enseeiht.fr
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