I am using mpi_comm_spawn_multiple to spawn multiple commands with argument lists. I am trying to do this in fortran (77) using version openmpi-1.4.1 and the ifort compiler v9.0. The operating system is SuSE Linux 10.1 (x86-64).
I have put together a simple controlling example program (test_pbload.F) and an example slave program (spray.F) to try and explain my problem.
In the controlling program mpi_comm_spawn_multiple is used to set 2 copies of the slave running. The first is started with the argument list "1 2 3 4" and the second with "5 6 7 8".
The slaves are started OK and the slaves print out the argument lists and exit. In addition the slaves print out their rank numbers so I can see which argument list belongs to which slave.
What I am finding is that the argument lists are not being sent to the slaves correctly, indeed both slaves seem to be getting both arguments lists !!!
To compile and run the programs I follow the steps below.
Controlling program "test_pbload.F"
mpif77 -o test_pbload test_pbload.F
Slave program "spray.F"
mpif77 -o spray spray.F
Run the controller
mpirun -np 1 test_pbload
The output of which is from the first slave:
nsize, mytid: iargs 2 0 : 2
spray: 0 1:1 2 3 4 < FIRST ARGUMENT
spray: 0 2:4 5 6 7 < SECOND ARGUMENT
and the second slave:
nsize, mytid: iargs 2 1 : 2
spray: 1 1:1 2 3 4 < FIRST ARGUMENT
spray: 1 2:4 5 6 7 < SECOND ARGUMENT
In each case the arguments (2 in both cases) are the same.
I have written a C version of the controlling program and everthing works as expected so I presume that I have either got the specification of the argument list wrong or I have discovered an error/bug. At the moment I working on the former -- but am at a loss to see what is wrong !!
Any help, pointers etc really appreciated.
Controlling program (that uses MPI_COMM_SPAWN_MULTIPLE) test_pbload.F
CHARACTER*25 commands(2), argvs(2, 2)
ncpus = 2
commands(1) = ' ./spray '
nprocs(1) = 1
info(1) = MPI_INFO_NULL
argvs(1, 1) = ' 1 2 3 4 '
argvs(1, 2) = ' '
commands(2) = ' ./spray '
nprocs(2) = 1
info(2) = MPI_INFO_NULL
argvs(2, 1) = ' 4 5 6 7 '
argvs(2, 2) = ' '
call mpi_comm_spawn_multiple( ncpus,
1 commands, argvs, nprocs, info,
2 0, MPI_COMM_WORLD, intercomm,
3 MPI_ERRCODES_IGNORE, error )
Slave program (started by the controlling program) spray.F
write(*,*) 'nsize, mytid: iargs', nsize, mytid, ":", iargs
if( iargs.gt.0 ) then
do i = 1, iargs
1 'spray: ',mytid,i,line(i)