This function uses MPI to spawn a process on a members of a group.
The full power of the underlying routine, MPI_Comm_spawn is not
yet available via the mpicommspawn routine in FreeMat. The
general syntax for its use is
errcodes = mpicommspawn(command,argv,maxprocs,root,comm)
where command is the command to execute, argv is a cell-array
of strings to pass as arguments to command, maxprocs is the
number of processes to spawn, root is the node that will actually
do the process spawn, and comm is the communicator to use.
If no communicator is specified, comm defaults to MPI_COMM_SELF.
If root is not specified, it defaults to 0. If maxprocs is
not specified, it defaults to 1. If argv is not specified no
arguments are passed to the spawned processes.