[petsc-users] Fortran interface -- low level access to petsc data

[Hossein Talebi]

Well, when dealing with Fortran I also often encounter software which
cannot be changed or upgraded to a more modern style.

What was in my mind is to create an interface additional to what is already
there in petsc. So this should be compiled along with anyone's code if the
used ocmpiler supports F03 or the necessary features of F03. This way the
older codes can be kept with the original F77 interface. Same thing they
did for Mpi and F03, F08 in the Mpi 3 standard if I'm not mistaken.





On Sun, Oct 27, 2013 at 8:51 PM, Tabrez Ali <stali at geology.wisc.edu> wrote:

>  On 10/27/2013 12:36 PM, Hossein Talebi wrote:
>
> Thank you for your answer.
>
>  It is not true that F2003 support is that limited: Gfortran, Intel
> Fortran, Cray Fortran, IBM Fortran and PGI Fortran all support nearly full
> F2003. Some other ones support the C portability of F2003 although not
> supporting the rest.
>
>
> You're 100% right but many systems often have older versions of these
> compilers that don't support the Fortran C interoperability. There is
> absolutely no excuse to not upgrade but then its not always possible.
>
> Unless there is a significant gain in functionality (or ease of support)
> by moving to a Fortran 2003 compiler it would be better to be conservative.
> One advantage of being able to build PETSc on a old enough system (e.g.,
> Debian Etch with GCC 4.1; glibc 2.4)  is that you can very easily build a
> static binary of your code and it will run pretty much on every Linux
> machine out there.
>
>
> T
>
>  * I can contribute on creating this interface. I have experience with
> F2003 to C++ and it works fine while C is a lot easier. My idea is to
> create the F03 interface to petsc as a separate tool. So, anyone trying to
> use petsc with a F03 compiler can compile this interface again to avoid the
> compiler inconsistency of Modules.
>
>  We can work on a python (or similar) script to generate the interfaces.
> For example, a project called gtk-fortran uses this method. Can any of you
> guys help a little for planning the interface design?
>
>
>  Cheers
> Hossein
>
>
>
>
>
>
>
>
>
>
>
>
> On Sun, Oct 27, 2013 at 4:42 PM, Satish Balay <balay at mcs.anl.gov> wrote:
>
>> On Sun, 27 Oct 2013, Matthew Knepley wrote:
>>
>> > On Sun, Oct 27, 2013 at 6:16 AM, Hossein Talebi <
>> talebi.hossein at gmail.com>wrote:
>> >
>> > >  Hello All,
>> > >
>> > > I am trying to use petsc with Fortran. The initial mechanism to use
>> petsc
>> > > with FORTRAN77 that works fine. However, I found the Fortran 90
>> interfaces
>> > > difficult to work with. The very first issue is one has to recompile
>> petsc
>> > > with the Fortran compiler in case different to the one which was used
>> to
>> > > create the Fortran Mod files.
>>
>>  Yes - one cannot mix fortran code compiled with 2 different compilers
>> - or 2 different version of the same compiler wrt modules.
>>
>> But we generally recommend not mixing compilers   for C aswell as
>> this
>> can cause problems.
>>
>> Also you don't need to use modules to get f90 interfaces. You can include
>> the f90 interface include files    directly in your code.
>>
>> #incude "finclude/petsc.h90"
>>
>> > > Also, we would still need to use C type
>> > > #include statements along with Fortran 'use' statement which is not so
>> > > optimal.
>>
>>  Even if you were to use f90 modules #include is unavoidable as we still
>> have other stuff in include files.
>>
>> check include/finclude/petscsysdef.h  include/finclude/petscsys.h
>>
>> > > Since Fortran 2003 offers great interface to C, did anyone try to
>> write a
>> > > F03 interface to petsc? Using F03 features, we can have very low data
>> > > access to petsc database as well.
>> > >
>> >
>> > F2003 support is fairly thin in the compiler world, and we have not had
>> > much call for it. We do gratefully accept contributions.
>>
>>  Currently we have the f90 interfaces [in include/finclude/ftn-auto/]
>> automatically generated by bfort tool from the C interface. So to
>> support F03 it would be ideal if there is such a tool. [or update
>> bfort to do it]
>>
>> Satish
>>
>
>
>
>
>
> --
> No one trusts a model except the one who wrote it; Everyone trusts an observation except the one who made it- Harlow Shapley
>
>


-- 
Dr.-Ing. Hossein Talebi

Bauhaus-Universität Weimar
Graudate Research School 1462 "Evaluation of Coupled Numerical and
Experimental Partial Models in Structural Engineering "
Postdoctoral Researcher

Berkaer Str. 9
99425 Weimar
Tel.: +49/3643/58 41 03
Fax:  +49/3643/58 41 01
E-Mail: hossein.talebi at uni-weimar.de <maximilian.huber at uni-weimar.de>
www.uni-weimar.de/grk1462
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20131028/87a52221/attachment.html>