Hello,
I'm having a problem with MPI_COMM_WORLD in Fortran 90. I have tried
with OpenMPI versions 1.2.6, 1.2.8 and 1.3. Both versions are compiled
with the PGI 8.0-2 suite. I've run the program in a debugger and with
"USE mpi" and MPI_COMM_WORLD returns 'Cannot find name
"MPI_COMM_WORLD"'. If I use "include mpif.h" results are a little
better: MPI_COMM_WORLD returns 0 (the initial value assigned by
mpif-common.h). The MPI functions don't seem to be affected by the fact
that MPI_COMM_WORLD is unset or equal to 0. For example, the following
works just fine:
CALL mpi_init (MyError)
CALL mpi_comm_rank (MPI_COMM_WORLD, MyRank, MyError)
CALL mpi_comm_size (MPI_COMM_WORLD, Nnodes, MyError)
even though, in the debugger, MPI_COMM_WORLD is unset or zero every step
of the way. However, when I try to us MPI_COMM_WORLD in a non MPI
standard function (Netcdf-4 in this case):
status=nf90_create_par(TRIM(ncname), &
& OR(nf90_clobber, nf90_netcdf4),
&
& MPI_COMM_WORLD, info, ncid)
I get the following error:
[daggoo:07640] *** An error occurred in MPI_Comm_dup
[daggoo:07640] *** on communicator MPI_COMM_WORLD
[daggoo:07640] *** MPI_ERR_COMM: invalid communicator
[daggoo:07640] *** MPI_ERRORS_ARE_FATAL (goodbye)
I have tried the exact same code compiled and run with MPICH2 (also PGI
8.0-2) and the problem does not occur.
If I have forgotten any details needed to debug this issue, please let
me know.
Thanks,
David Robertson
