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Rmpi

Rmpi is R with mpi support. On the barley this means OpenMPI. Rmpi can be installed from CRAN packages if you wish to have the latest version. As a convenience Rmpi_0.5-9 is installed on the barley in /mnt/glusterfs/apps/R. The setup section following this one will describe how to setup Rmpi so that you may submit jobs to the barley cluster.

setup

grid engine submit script (rmpi.submit)

#
#$ -cwd 
#$ -j y 
#$ -S /bin/bash 
#$ -N rmpi32 
#$ -pe orte 32

tmphosts=`mktemp` awk '{ for (i=0; i < $2; ++i) { print $1} }' $PE_HOSTFILE > $tmphosts 

echo "Got $NSLOTS slots"
echo "jobid $JOB_ID"

mpirun -np $NSLOTS -machinefile $tmphosts R --no-save -q < Rmpitest.R

Save following as .Rprofile. This should be in the current directory from where you submit your Rmpi jobs

# This R profile can be used when a cluster does not allow spawning or a job 
# scheduler is required to launch any parallel jobs. Saving this file as 
# .Rprofile in the working directory or root directory. For unix platform, run 
# mpirexec -n [cpu numbers] R --no-save -q 
# For windows platform with mpich2, use mpiexec wrapper and specify a working 
# directory where .Rprofile is inside. 
# Cannot be used as Rprofile.site because it will not work

# Following system libraries are not loaded automatically. So manual loads are 
# needed.


.libPaths(c("/mnt/glusterfs/apps/R", "/usr/lib/R/library"))

library(utils)
library(stats)
library(datasets)
library(grDevices)
library(graphics)
library(methods)

if (!invisible(library(Rmpi,logical.return = TRUE))){
    warning("Rmpi cannot be loaded")
    q(save = "no")
}

options(error=quote(assign(".mpi.err", FALSE, env = .GlobalEnv)))

if (mpi.comm.size(0) > 1)
    invisible(mpi.comm.dup(0,1))

if (mpi.comm.rank(0) >0){
    #sys.load.image(".RData",TRUE)
    options(echo=FALSE)
    .comm <- 1
    mpi.barrier(0)
    repeat 
	try(eval(mpi.bcast.cmd(rank=0,comm=.comm)),TRUE)
	#try(eval(mpi.bcast.cmd(rank=0,comm=.comm),env=sys.parent()),TRUE)
    #mpi.barrier(.comm)
    if (is.loaded("mpi_comm_disconnect")) 
        mpi.comm.disconnect(.comm)
    else mpi.comm.free(.comm)
    mpi.quit()
}
    
if (mpi.comm.rank(0)==0) {
    #options(echo=TRUE)
    mpi.barrier(0)
    if(mpi.comm.size(0) > 1)
        slave.hostinfo(1)
}

.Last <- function(){
    if (is.loaded("mpi_initialize")){
        if (mpi.comm.size(1) > 1){
            print("Please use mpi.close.Rslaves() to close slaves")
            mpi.close.Rslaves(comm=1)
    	}
    }
    print("Please use mpi.quit() to quit R")
    mpi.quit()
}

Here is a very short R program. Save this as Rmpitest.R

# Tell all slaves to return a message identifying themselves

mpi.remote.exec(paste("I am",mpi.comm.rank(),"of",mpi.comm.size())) 

# Tell all slaves to close down, and exit the program

mpi.close.Rslaves()
mpi.quit()

running

If you look at the first few lines of rmpi.submit you will see -pe orte 32. This indicates to grid engine to allocate 32 slots, across any hosts.

Lets submit the job:

bishopj@corn14:/mnt/glusterfs/bishopj$ qsub rmpi.submit
Your job 81714 ("rmpi32") has been submitted
bishopj@corn14:/mnt/glusterfs/bishopj$ cat rmpi32.o81714
Got 32 slots
jobid 81714

master  (rank 0 , comm 1) of size 32 is running on: barley01 
slave1  (rank 1 , comm 1) of size 32 is running on: barley01 
slave2  (rank 2 , comm 1) of size 32 is running on: barley04 
slave3  (rank 3 , comm 1) of size 32 is running on: barley04 
... ... ...
slave30 (rank 30, comm 1) of size 32 is running on: barley11 
slave31 (rank 31, comm 1) of size 32 is running on: barley20 
> 
> # Tell all slaves to return a message identifying themselves
> mpi.remote.exec(paste("I am",mpi.comm.rank(),"of",mpi.comm.size()))
$slave1
[1] "I am 1 of 32"

$slave2
[1] "I am 2 of 32"

$slave3
[1] "I am 3 of 32"

$slave4
[1] "I am 4 of 32"

$slave5
[1] "I am 5 of 32"

$slave6
[1] "I am 6 of 32"

$slave7
[1] "I am 7 of 32"

$slave8
[1] "I am 8 of 32"

$slave9
[1] "I am 9 of 32"

$slave10
[1] "I am 10 of 32"

$slave11
[1] "I am 11 of 32"

$slave12
[1] "I am 12 of 32"

$slave13
[1] "I am 13 of 32"

$slave14
[1] "I am 14 of 32"

$slave15
[1] "I am 15 of 32"

$slave16
[1] "I am 16 of 32"

$slave17
[1] "I am 17 of 32"

$slave18
[1] "I am 18 of 32"

$slave19
[1] "I am 19 of 32"

$slave20
[1] "I am 20 of 32"

$slave21
[1] "I am 21 of 32"

$slave22
[1] "I am 22 of 32"

$slave23
[1] "I am 23 of 32"

$slave24
[1] "I am 24 of 32"

$slave25
[1] "I am 25 of 32"

$slave26
[1] "I am 26 of 32"

$slave27
[1] "I am 27 of 32"

$slave28
[1] "I am 28 of 32"

$slave29
[1] "I am 29 of 32"

$slave30
[1] "I am 30 of 32"

$slave31
[1] "I am 31 of 32"

> 
> # Tell all slaves to close down, and exit the program
> mpi.close.Rslaves()
[1] 1
> mpi.quit()