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Subject: Re: [OMPI devel] Fortran 90 Interface
From: David Robertson (robertson_at_[hidden])
Date: 2009-01-23 00:30:28


>> I don't know how helpful this code will be unless you happen to have
>> HDF5/NetCDF4 already installed. I looked at the code NetCDF4 uses to
>> test parallel IO but it is all in C so it wasn't very helpful. If you
>> have the NetCDF4 source code the parallel IO tests are in the nc_test4
>> directory.
>
> Mm, yes, that would be difficult for me to build/run. Can you or your
> developer trim it down to a small independent example?

I will talk to the developer tomorrow to see if he can come up with an
independent example.

> FWIW, this is not happening for me -- I can call subroutines or
> functions with MPI_COMM_WORLD and then use that value (which should be
> 0, btw) to call an MPI function such as MPI_COMM_DUP.
>
> Per your prior comment about the debugging not being able to find
> MPI_COMM_WORLD -- perhaps the compiler is optimizing it out...? Or
> perhaps it was transmorgified to lower case (i.e., try seeing if
> "mpi_comm_world" exists -- I see it in your mpi.mod file)...?

I have looked for both MPI_COMM_WORLD and mpi_comm_world but neither can
be found by totalview (the parallel debugger we use) when I compile with
"USE mpi". When I use "include 'mpif.h'" both MPI_COMM_WORLD and
mpi_comm_world are zero. MPI_COMM_WORLD is set to a large integer
(1140850688) in MPICH2 so I wonder if there is something in HDF5 and/or
NetCDF4 that doesn't like 0 for the communicator handle. At any rate,
you have given me some ideas of things to check in the debugger
tomorrow. Is there a safe way to change what MPI_COMM_WORLD is set to in
OpenMPI?

I have tried the code I sent you with ifort and gfortran compilations of
OpenMPI 1.3 with identical results so I don't think it's PGI's fault.

Let me know on that MPI_COMM_WORLD value and I'll get back to you tomorrow.

Thanks,
Dave