[R-sig-Debian] rmpi/snow grabs all available CPU

[Dirk Eddelbuettel]

Faheem,

There is another difference. 

Under LAM, you could start R rightaway and it would find the hosts for MPI on
the net.

Under OpenMPI, I do something like

      orterun --hostfile ~/.my-ompi-hosts -np 1 R --no-save    

and then use

      cl <- makeCluster(spec=N, type="MPI")

to start 'N' nodes.  Note how orterun is instrumented to use just one
'outer' R node (our master) which will then spawn the 'inner' N nodes.

If I launch things this way things behave better.   I'd invite other to share
their tips and tricks :)

Hth, Dirk

-- 
Three out of two people have difficulties with fractions.