[mpich-discuss] mpifort wrapper compiler?

[Jeff Hammond]

> Is this MPICH, or IBM MPI?

That dichotomy is dated, but not particularly relevant for this discussion.

> When I install MPICH 3.x on my Linux commodity cluster, I only see mpif77 and mpif90.  Does MPICH do something different when installed on a BG system?

IBM deploys MPICH for BG with a bunch of wrappers, one for each bgxl*
compiler (including an _r variant for each as well).  They are named
mpixl* to prevent confusion with the GCC wrappers, at least when some
variants of MPI are used.  See
https://wiki.alcf.anl.gov/parts/index.php/Mira_MPI_Documentation#Explanation_of_MPI_variants
for details.  If you have further questions, request an ALCF account
and you can dig around yourself :-)

>> By default, XLF does not enforce strict language compliance, but it
>> will enforce a wide range of syntax requirements that cause user codes
>> to fail to compile.  I recall more than one case where Fortran 2003
>> and 2008 differ just slightly and users have to use the compiler
>> associated with precisely the language that they are trying to use.
>
> Fair enough.
>
> But I'm trying to determine if MPICH really has mpif03 and mpif08, or whether you were using IBM's MPI, or whether you used MPICH's "mpif90" with some appropriate flag to force a particular syntax/dialect.

MPICH does not have these, but I don't see why it would today given
that it only supports the F77 and F90 interfaces.  Whether or not
mpif08 is required depends on whether or not the Fortran compiler is
indifferent to all syntax between 1990 and 2008+.

Jeff

-- 
Jeff Hammond
jeff.science at gmail.com