[MPIWG Fortran] ticket 351

[Jeff Hammond]

On Mon, Nov 9, 2015 at 6:37 AM, Bill Long <longb at cray.com> wrote:

>
> On Nov 9, 2015, at 8:24 AM, Jeff Hammond <jeff.science at gmail.com> wrote:
>
> > Did you read the ticket?  We need this for the same reason MPI_Init()
> takes argc/argv even though C main() already has them.
>
> But the C standard does not implicitly assume every program is parallel.
>
>
Correct.  Nor can MPI assume that argc/argv will magically appear on the
compute nodes when the job is launched from somewhere else.


> >
> > While it may be true that process managers are magically fixing
> argc/argv, this is not guaranteed by any standard.
>
> The Fortran standard is intentionally vague to allow for environments
> where there is no command line, but rather (for example) the code starts
> executing by clicking a graphic button on the screen.  The standard is
> likely to not include specific words about program launchers that might
> turn into bit rot in the future.   If your favorite compiler returns the
> launcher text as part of the command line, complain.
>
>
Complaining is fun, but has no teeth without a standard.  Many vendors are
quite strict about standards and reject feature requests that improve user
experience if they lack justification in a standard.  I can cite numerous
vendors here...


> While the new proposed routines are trivial to implement (assuming they
> have the same arguments as the corresponding Fortran ones),  they add to
> one of MPI’s most serious flaws - way to many routines already.
>
>
As you say, they are trivial to implement.  The size of the standard is an
irrelevant argument.  Users don't read what they don't need to read and
users shouldn't be reading the spec most of the time anyways.

Jeff


> Cheers,
> Bill
>
>
> >
> > Jeff
> >
> > On Mon, Nov 9, 2015 at 6:21 AM, Bill Long <longb at cray.com> wrote:
> > Hi Jeff,
> >
> > I don’t see the value of this.  The Fortran intrinsics GET_COMMAND and
> friends should already do what you want.  Fortran programs are now presumed
> parallel. The intrinsics should know how to strip off the “launcher” part
> of the command line.  At least that is how the Cray versions have worked
> from the beginning.   Experiments are  in order for other vendors, as a
> check.
> >
> > Cheers,
> > Bill
> >
> >
> >
> > On Nov 9, 2015, at 8:13 AM, Jeff Hammond <jeff.science at gmail.com> wrote:
> >
> > > we did a lot of work on
> https://svn.mpi-forum.org/trac/mpi-forum-web/ticket/351.  do we intend to
> move forward this for MPI 4+?  if yes, we need to migrate the trac ticket
> to a github issue.
> > >
> > > jeff
> > >
> > > --
> > > Jeff Hammond
> > > jeff.science at gmail.com
> > > http://jeffhammond.github.io/
> > > _______________________________________________
> > > mpiwg-fortran mailing list
> > > mpiwg-fortran at lists.mpi-forum.org
> > > http://lists.mpi-forum.org/mailman/listinfo.cgi/mpiwg-fortran
> >
> > Bill Long
>        longb at cray.com
> > Fortran Technical Support  &                                  voice:
> 651-605-9024
> > Bioinformatics Software Development                     fax:
> 651-605-9142
> > Cray Inc./ Cray Plaza, Suite 210/ 380 Jackson St./ St. Paul, MN 55101
> >
> >
> > _______________________________________________
> > mpiwg-fortran mailing list
> > mpiwg-fortran at lists.mpi-forum.org
> > http://lists.mpi-forum.org/mailman/listinfo.cgi/mpiwg-fortran
> >
> >
> >
> > --
> > Jeff Hammond
> > jeff.science at gmail.com
> > http://jeffhammond.github.io/
> > _______________________________________________
> > mpiwg-fortran mailing list
> > mpiwg-fortran at lists.mpi-forum.org
> > http://lists.mpi-forum.org/mailman/listinfo.cgi/mpiwg-fortran
>
> Bill Long
>      longb at cray.com
> Fortran Technical Support  &                                  voice:
> 651-605-9024
> Bioinformatics Software Development                     fax:  651-605-9142
> Cray Inc./ Cray Plaza, Suite 210/ 380 Jackson St./ St. Paul, MN 55101
>
>
> _______________________________________________
> mpiwg-fortran mailing list
> mpiwg-fortran at lists.mpi-forum.org
> http://lists.mpi-forum.org/mailman/listinfo.cgi/mpiwg-fortran
>



-- 
Jeff Hammond
jeff.science at gmail.com
http://jeffhammond.github.io/
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