> What I want is to spawn a bunch of R slaves to other machines on
> the network. I can spawn R slaves, as many as I like, to the local
> machine, but I don t know how to do this with machines on the
> network. That s what hosts parameter of mpi.spawn.Rslaves()
> enables me to do, I think. If I can do that, then Rmpi has
> function(s) to send command to each of the spawned slaves.
> My question is how can I get open MPI to give me those hosts
I am not quite sure if I understood your question, but when you
read "man MPI_Comm_spawn" you can find the parameter "MPI_Info info"
which allows to specify where and how to start processes. "man
MPI_Info_create" shows you how to create an info object and "man
MPI_Info_set" how to add a key/value pair. "man orte_hosts" shows
you how you can build a hostfile. I do not know how to do these
things in your language R but hopefully the information of the
manual pages helps to solve your problem.