>>> 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?
>> No. Open MPI's Fortran MPI_COMM_WORLD is pretty much hard-wired to 0.
> That's a mistake. But probably non-trivial to fix.
I'm a little confused as to what you mean. What are you saying is a
mistake? That Open MPI's Fortran MPI_COMM_WORLD is hard-wired to 0? That
MPICH2 setting MPI_COMM_WORLD to 1140850688? or that HDF5 and/or
NetCDF-4 may not like 0 for a communicator handle?