Hi,
I have tried in 2 different clusters, and both times I have problems using the headed node together with a headless one. There is no problem if I run 2 processes on n0, or 2 processes on n1, or on n2. No problem either using n1 and n2. The problem is when I try to use n0 and n1, or n0 and n2.
Previously I thought it was a cluster configuration problem. http://www.open-mpi.org/community/lists/users/2006/04/1094.php but now I am the sysadmin and don't know why this happens.I'm attaching config.log, the ompi_info output, and the mpirun -d output for both a working command (n1,n2) and one who blocks (n0,n2). The hello program is the typical "I am n/m" example.
Thanks for your help -javier
config.log.bz2
Description: BZip2 compressed data
Open MPI: 1.0.2
Open MPI SVN revision: r9571
Open RTE: 1.0.2
Open RTE SVN revision: r9571
OPAL: 1.0.2
OPAL SVN revision: r9571
Prefix: /home/javier/openmpi-1.0.2
Configured architecture: i686-pc-linux-gnu
Configured by: javier
Configured on: Mon Apr 24 20:47:06 CEST 2006
Configure host: oxigeno.ugr.es
Built by: javier
Built on: lun abr 24 21:24:27 CEST 2006
Built host: oxigeno.ugr.es
C bindings: yes
C++ bindings: yes
Fortran77 bindings: yes (all)
Fortran90 bindings: no
C compiler: gcc
C compiler absolute: /usr/bin/gcc
C++ compiler: g++
C++ compiler absolute: /usr/bin/g++
Fortran77 compiler: g77
Fortran77 compiler abs: /usr/bin/g77
Fortran90 compiler: none
Fortran90 compiler abs: none
C profiling: yes
C++ profiling: yes
Fortran77 profiling: yes
Fortran90 profiling: no
C++ exceptions: no
Thread support: posix (mpi: yes, progress: yes)
Internal debug support: no
MPI parameter check: runtime
Memory profiling support: no
Memory debugging support: no
libltdl support: 1
MCA memory: malloc_interpose (MCA v1.0, API v1.0, Component
v1.0.2)
MCA paffinity: linux (MCA v1.0, API v1.0, Component v1.0.2)
MCA maffinity: first_use (MCA v1.0, API v1.0, Component v1.0.2)
MCA timer: linux (MCA v1.0, API v1.0, Component v1.0.2)
MCA allocator: basic (MCA v1.0, API v1.0, Component v1.0)
MCA allocator: bucket (MCA v1.0, API v1.0, Component v1.0)
MCA coll: basic (MCA v1.0, API v1.0, Component v1.0.2)
MCA coll: self (MCA v1.0, API v1.0, Component v1.0.2)
MCA coll: sm (MCA v1.0, API v1.0, Component v1.0.2)
MCA io: romio (MCA v1.0, API v1.0, Component v1.0.2)
MCA mpool: sm (MCA v1.0, API v1.0, Component v1.0.2)
MCA pml: ob1 (MCA v1.0, API v1.0, Component v1.0.2)
MCA pml: teg (MCA v1.0, API v1.0, Component v1.0.2)
MCA bml: r2 (MCA v1.0, API v1.0, Component v1.0.2)
MCA bml: r2 (MCA v1.0, API v1.0, Component v1.0.2)
MCA ptl: self (MCA v1.0, API v1.0, Component v1.0.2)
MCA ptl: sm (MCA v1.0, API v1.0, Component v1.0.2)
MCA ptl: tcp (MCA v1.0, API v1.0, Component v1.0.2)
MCA btl: self (MCA v1.0, API v1.0, Component v1.0.2)
MCA btl: sm (MCA v1.0, API v1.0, Component v1.0.2)
MCA btl: tcp (MCA v1.0, API v1.0, Component v1.0)
MCA topo: unity (MCA v1.0, API v1.0, Component v1.0.2)
MCA gpr: null (MCA v1.0, API v1.0, Component v1.0.2)
MCA gpr: proxy (MCA v1.0, API v1.0, Component v1.0.2)
MCA gpr: replica (MCA v1.0, API v1.0, Component v1.0.2)
MCA iof: proxy (MCA v1.0, API v1.0, Component v1.0.2)
MCA iof: svc (MCA v1.0, API v1.0, Component v1.0.2)
MCA ns: proxy (MCA v1.0, API v1.0, Component v1.0.2)
MCA ns: replica (MCA v1.0, API v1.0, Component v1.0.2)
MCA oob: tcp (MCA v1.0, API v1.0, Component v1.0)
MCA ras: dash_host (MCA v1.0, API v1.0, Component v1.0.2)
MCA ras: hostfile (MCA v1.0, API v1.0, Component v1.0.2)
MCA ras: localhost (MCA v1.0, API v1.0, Component v1.0.2)
MCA ras: slurm (MCA v1.0, API v1.0, Component v1.0.2)
MCA rds: hostfile (MCA v1.0, API v1.0, Component v1.0.2)
MCA rds: resfile (MCA v1.0, API v1.0, Component v1.0.2)
MCA rmaps: round_robin (MCA v1.0, API v1.0, Component v1.0.2)
MCA rmgr: proxy (MCA v1.0, API v1.0, Component v1.0.2)
MCA rmgr: urm (MCA v1.0, API v1.0, Component v1.0.2)
MCA rml: oob (MCA v1.0, API v1.0, Component v1.0.2)
MCA pls: daemon (MCA v1.0, API v1.0, Component v1.0.2)
MCA pls: fork (MCA v1.0, API v1.0, Component v1.0.2)
MCA pls: proxy (MCA v1.0, API v1.0, Component v1.0.2)
MCA pls: rsh (MCA v1.0, API v1.0, Component v1.0.2)
MCA pls: slurm (MCA v1.0, API v1.0, Component v1.0.2)
MCA sds: env (MCA v1.0, API v1.0, Component v1.0.2)
MCA sds: pipe (MCA v1.0, API v1.0, Component v1.0.2)
MCA sds: seed (MCA v1.0, API v1.0, Component v1.0.2)
MCA sds: singleton (MCA v1.0, API v1.0, Component v1.0.2)
MCA sds: slurm (MCA v1.0, API v1.0, Component v1.0.2)
Script iniciado (Tue Apr 25 11:23:37 2006
)
[javier@oxigeno hello]$ mpirun -d -c 2 -H ox1,ox2 hello
[oxigeno.ugr.es:29960] [0,0,0] setting up session dir with
[oxigeno.ugr.es:29960] universe default-universe
[oxigeno.ugr.es:29960] user javier
[oxigeno.ugr.es:29960] host oxigeno.ugr.es
[oxigeno.ugr.es:29960] jobid 0
[oxigeno.ugr.es:29960] procid 0
[oxigeno.ugr.es:29960] procdir:
/tmp/openmpi-sessions-jav...@oxigeno.ugr.es_0/default-universe/0/0
[oxigeno.ugr.es:29960] jobdir:
/tmp/openmpi-sessions-jav...@oxigeno.ugr.es_0/default-universe/0
[oxigeno.ugr.es:29960] unidir:
/tmp/openmpi-sessions-jav...@oxigeno.ugr.es_0/default-universe
[oxigeno.ugr.es:29960] top: openmpi-sessions-jav...@oxigeno.ugr.es_0
[oxigeno.ugr.es:29960] tmp: /tmp
[oxigeno.ugr.es:29960] [0,0,0] contact_file
/tmp/openmpi-sessions-jav...@oxigeno.ugr.es_0/default-universe/universe-setup.txt
[oxigeno.ugr.es:29960] [0,0,0] wrote setup file
[oxigeno.ugr.es:29960] spawn: in job_state_callback(jobid = 1, state = 0x1)
[oxigeno.ugr.es:29960] pls:rsh: local csh: 0, local bash: 1
[oxigeno.ugr.es:29960] pls:rsh: assuming same remote shell as local shell
[oxigeno.ugr.es:29960] pls:rsh: remote csh: 0, remote bash: 1
[oxigeno.ugr.es:29960] pls:rsh: final template argv:
[oxigeno.ugr.es:29960] pls:rsh: /usr/bin/ssh <template> orted --debug
--bootproxy 1 --name <template> --num_procs 3 --vpid_start 0 --nodename
<template> --universe jav...@oxigeno.ugr.es:default-universe --nsreplica
"0.0.0;tcp://150.214.191.217:1220;tcp://192.168.1.9:1220" --gprreplica
"0.0.0;tcp://150.214.191.217:1220;tcp://192.168.1.9:1220" --mpi-call-yield 0
[oxigeno.ugr.es:29960] pls:rsh: launching on node ox1
[oxigeno.ugr.es:29960] pls:rsh: not oversubscribed -- setting
mpi_yield_when_idle to 0
[oxigeno.ugr.es:29960] pls:rsh: ox1 is a REMOTE node
[oxigeno.ugr.es:29960] pls:rsh: executing: /usr/bin/ssh ox1 orted --debug
--bootproxy 1 --name 0.0.1 --num_procs 3 --vpid_start 0 --nodename ox1
--universe jav...@oxigeno.ugr.es:default-universe --nsreplica
"0.0.0;tcp://150.214.191.217:1220;tcp://192.168.1.9:1220" --gprreplica
"0.0.0;tcp://150.214.191.217:1220;tcp://192.168.1.9:1220" --mpi-call-yield 0
[oxigeno.ugr.es:29960] pls:rsh: launching on node ox2
[oxigeno.ugr.es:29960] pls:rsh: not oversubscribed -- setting
mpi_yield_when_idle to 0
[oxigeno.ugr.es:29960] pls:rsh: ox2 is a REMOTE node
[oxigeno.ugr.es:29960] pls:rsh: executing: /usr/bin/ssh ox2 orted --debug
--bootproxy 1 --name 0.0.2 --num_procs 3 --vpid_start 0 --nodename ox2
--universe jav...@oxigeno.ugr.es:default-universe --nsreplica
"0.0.0;tcp://150.214.191.217:1220;tcp://192.168.1.9:1220" --gprreplica
"0.0.0;tcp://150.214.191.217:1220;tcp://192.168.1.9:1220" --mpi-call-yield 0
[ox1:21646] [0,0,1] setting up session dir with
[ox1:21646] universe default-universe
[ox1:21646] user javier
[ox1:21646] host ox1
[ox1:21646] jobid 0
[ox1:21646] procid 1
[ox1:21646] procdir: /tmp/openmpi-sessions-javier@ox1_0/default-universe/0/1
[ox1:21646] jobdir: /tmp/openmpi-sessions-javier@ox1_0/default-universe/0
[ox1:21646] unidir: /tmp/openmpi-sessions-javier@ox1_0/default-universe
[ox1:21646] top: openmpi-sessions-javier@ox1_0
[ox1:21646] tmp: /tmp
[ox1:21735] [0,1,0] setting up session dir with
[ox1:21735] universe default-universe
[ox1:21735] user javier
[ox1:21735] host ox1
[ox1:21735] jobid 1
[ox1:21735] procid 0
[ox1:21735] procdir: /tmp/openmpi-sessions-javier@ox1_0/default-universe/1/0
[ox1:21735] jobdir: /tmp/openmpi-sessions-javier@ox1_0/default-universe/1
[ox1:21735] unidir: /tmp/openmpi-sessions-javier@ox1_0/default-universe
[ox1:21735] top: openmpi-sessions-javier@ox1_0
[ox1:21735] tmp: /tmp
[ox2:22211] [0,0,2] setting up session dir with
[ox2:22211] universe default-universe
[ox2:22211] user javier
[ox2:22211] host ox2
[ox2:22211] jobid 0
[ox2:22211] procid 2
[ox2:22211] procdir: /tmp/openmpi-sessions-javier@ox2_0/default-universe/0/2
[ox2:22211] jobdir: /tmp/openmpi-sessions-javier@ox2_0/default-universe/0
[ox2:22211] unidir: /tmp/openmpi-sessions-javier@ox2_0/default-universe
[ox2:22211] top: openmpi-sessions-javier@ox2_0
[ox2:22211] tmp: /tmp
[ox2:22300] [0,1,1] setting up session dir with
[ox2:22300] universe default-universe
[ox2:22300] user javier
[ox2:22300] host ox2
[ox2:22300] jobid 1
[ox2:22300] procid 1
[ox2:22300] procdir: /tmp/openmpi-sessions-javier@ox2_0/default-universe/1/1
[ox2:22300] jobdir: /tmp/openmpi-sessions-javier@ox2_0/default-universe/1
[ox2:22300] unidir: /tmp/openmpi-sessions-javier@ox2_0/default-universe
[ox2:22300] top: openmpi-sessions-javier@ox2_0
[ox2:22300] tmp: /tmp
[oxigeno.ugr.es:29960] spawn: in job_state_callback(jobid = 1, state = 0x3)
[oxigeno.ugr.es:29960] Info: Setting up debugger process table for applications
MPIR_being_debugged = 0
MPIR_debug_gate = 0
MPIR_debug_state = 1
MPIR_acquired_pre_main = 0
MPIR_i_am_starter = 0
MPIR_proctable_size = 2
MPIR_proctable:
(i, host, exe, pid) = (0, ox2, hello, 22300)
(i, host, exe, pid) = (1, ox1, hello, 21735)
[ox1:21646] orted: job_state_callback(jobid = 1, state = 134643904)
[ox2:22211] orted: job_state_callback(jobid = 1, state = 134640784)
[oxigeno.ugr.es:29960] spawn: in job_state_callback(jobid = 1, state = 0x4)
[ox2:22211] orted: job_state_callback(jobid = 1, state = 134640784)
[ox1:21646] orted: job_state_callback(jobid = 1, state = 134643312)
Hello, world! I am 1 of 2
Hello, world! I am 0 of 2
[ox1:21735] [0,1,0] ompi_mpi_init completed
[ox2:22300] [0,1,1] ompi_mpi_init completed
[oxigeno.ugr.es:29960] spawn: in job_state_callback(jobid = 1, state = 0x7)
[oxigeno.ugr.es:29960] spawn: in job_state_callback(jobid = 1, state = 0x8)
[ox2:22211] orted: job_state_callback(jobid = 1, state = 134640408)
[ox2:22211] orted: job_state_callback(jobid = 1, state = 134611224)
[ox1:21646] orted: job_state_callback(jobid = 1, state = 134643320)
[ox1:21646] orted: job_state_callback(jobid = 1, state = 134611424)
[ox2:22300] sess_dir_finalize: found proc session dir empty - deleting
[ox1:21735] sess_dir_finalize: found proc session dir empty - deleting
[ox2:22300] sess_dir_finalize: job session dir not empty - leaving
[ox1:21735] sess_dir_finalize: job session dir not empty - leaving
[ox1:21646] sess_dir_finalize: proc session dir not empty - leaving
[ox2:22211] sess_dir_finalize: proc session dir not empty - leaving
[ox2:22211] orted: job_state_callback(jobid = 1, state =
ORTE_PROC_STATE_TERMINATED)
[ox1:21646] orted: job_state_callback(jobid = 1, state =
ORTE_PROC_STATE_TERMINATED)
[ox1:21646] sess_dir_finalize: found job session dir empty - deleting
[ox2:22211] sess_dir_finalize: found job session dir empty - deleting
[ox1:21646] sess_dir_finalize: univ session dir not empty - leaving
[ox2:22211] sess_dir_finalize: univ session dir not empty - leaving
[ox1:21646] sess_dir_finalize: found proc session dir empty - deleting
[ox2:22211] sess_dir_finalize: found proc session dir empty - deleting
[ox1:21646] sess_dir_finalize: found job session dir empty - deleting
[ox2:22211] sess_dir_finalize: found job session dir empty - deleting
[ox2:22211] sess_dir_finalize: found univ session dir empty - deleting
[ox1:21646] sess_dir_finalize: found univ session dir empty - deleting
[ox2:22211] sess_dir_finalize: found top session dir empty - deleting
[ox1:21646] sess_dir_finalize: found top session dir empty - deleting
[javier@oxigeno hello]$ exit
Script terminado (Tue Apr 25 11:24:10 2006
)
Script iniciado (Tue Apr 25 11:24:26 2006
)
[javier@oxigeno hello]$ mpirun -d -c 2 -H ox0,ox2 hello
[oxigeno.ugr.es:30067] [0,0,0] setting up session dir with
[oxigeno.ugr.es:30067] universe default-universe
[oxigeno.ugr.es:30067] user javier
[oxigeno.ugr.es:30067] host oxigeno.ugr.es
[oxigeno.ugr.es:30067] jobid 0
[oxigeno.ugr.es:30067] procid 0
[oxigeno.ugr.es:30067] procdir:
/tmp/openmpi-sessions-jav...@oxigeno.ugr.es_0/default-universe/0/0
[oxigeno.ugr.es:30067] jobdir:
/tmp/openmpi-sessions-jav...@oxigeno.ugr.es_0/default-universe/0
[oxigeno.ugr.es:30067] unidir:
/tmp/openmpi-sessions-jav...@oxigeno.ugr.es_0/default-universe
[oxigeno.ugr.es:30067] top: openmpi-sessions-jav...@oxigeno.ugr.es_0
[oxigeno.ugr.es:30067] tmp: /tmp
[oxigeno.ugr.es:30067] [0,0,0] contact_file
/tmp/openmpi-sessions-jav...@oxigeno.ugr.es_0/default-universe/universe-setup.txt
[oxigeno.ugr.es:30067] [0,0,0] wrote setup file
[oxigeno.ugr.es:30067] spawn: in job_state_callback(jobid = 1, state = 0x1)
[oxigeno.ugr.es:30067] pls:rsh: local csh: 0, local bash: 1
[oxigeno.ugr.es:30067] pls:rsh: assuming same remote shell as local shell
[oxigeno.ugr.es:30067] pls:rsh: remote csh: 0, remote bash: 1
[oxigeno.ugr.es:30067] pls:rsh: final template argv:
[oxigeno.ugr.es:30067] pls:rsh: /usr/bin/ssh <template> orted --debug
--bootproxy 1 --name <template> --num_procs 3 --vpid_start 0 --nodename
<template> --universe jav...@oxigeno.ugr.es:default-universe --nsreplica
"0.0.0;tcp://150.214.191.217:1223;tcp://192.168.1.9:1223" --gprreplica
"0.0.0;tcp://150.214.191.217:1223;tcp://192.168.1.9:1223" --mpi-call-yield 0
[oxigeno.ugr.es:30067] pls:rsh: launching on node ox0
[oxigeno.ugr.es:30067] pls:rsh: not oversubscribed -- setting
mpi_yield_when_idle to 0
[oxigeno.ugr.es:30067] pls:rsh: ox0 is a LOCAL node
[oxigeno.ugr.es:30067] pls:rsh: changing to directory /home/javier
[oxigeno.ugr.es:30067] pls:rsh: executing: orted --debug --bootproxy 1 --name
0.0.1 --num_procs 3 --vpid_start 0 --nodename ox0 --universe
jav...@oxigeno.ugr.es:default-universe --nsreplica
"0.0.0;tcp://150.214.191.217:1223;tcp://192.168.1.9:1223" --gprreplica
"0.0.0;tcp://150.214.191.217:1223;tcp://192.168.1.9:1223" --mpi-call-yield 0
[oxigeno.ugr.es:30070] [0,0,1] setting up session dir with
[oxigeno.ugr.es:30070] universe default-universe
[oxigeno.ugr.es:30070] user javier
[oxigeno.ugr.es:30070] host ox0
[oxigeno.ugr.es:30070] jobid 0
[oxigeno.ugr.es:30070] procid 1
[oxigeno.ugr.es:30070] procdir:
/tmp/openmpi-sessions-javier@ox0_0/default-universe/0/1
[oxigeno.ugr.es:30070] jobdir:
/tmp/openmpi-sessions-javier@ox0_0/default-universe/0
[oxigeno.ugr.es:30070] unidir:
/tmp/openmpi-sessions-javier@ox0_0/default-universe
[oxigeno.ugr.es:30070] top: openmpi-sessions-javier@ox0_0
[oxigeno.ugr.es:30070] tmp: /tmp
[oxigeno.ugr.es:30067] pls:rsh: launching on node ox2
[oxigeno.ugr.es:30067] pls:rsh: not oversubscribed -- setting
mpi_yield_when_idle to 0
[oxigeno.ugr.es:30067] pls:rsh: ox2 is a REMOTE node
[oxigeno.ugr.es:30067] pls:rsh: executing: /usr/bin/ssh ox2 orted --debug
--bootproxy 1 --name 0.0.2 --num_procs 3 --vpid_start 0 --nodename ox2
--universe jav...@oxigeno.ugr.es:default-universe --nsreplica
"0.0.0;tcp://150.214.191.217:1223;tcp://192.168.1.9:1223" --gprreplica
"0.0.0;tcp://150.214.191.217:1223;tcp://192.168.1.9:1223" --mpi-call-yield 0
[oxigeno.ugr.es:30076] [0,1,0] setting up session dir with
[oxigeno.ugr.es:30076] universe default-universe
[oxigeno.ugr.es:30076] user javier
[oxigeno.ugr.es:30076] host ox0
[oxigeno.ugr.es:30076] jobid 1
[oxigeno.ugr.es:30076] procid 0
[oxigeno.ugr.es:30076] procdir:
/tmp/openmpi-sessions-javier@ox0_0/default-universe/1/0
[oxigeno.ugr.es:30076] jobdir:
/tmp/openmpi-sessions-javier@ox0_0/default-universe/1
[oxigeno.ugr.es:30076] unidir:
/tmp/openmpi-sessions-javier@ox0_0/default-universe
[oxigeno.ugr.es:30076] top: openmpi-sessions-javier@ox0_0
[oxigeno.ugr.es:30076] tmp: /tmp
[ox2:22311] [0,0,2] setting up session dir with
[ox2:22311] universe default-universe
[ox2:22311] user javier
[ox2:22311] host ox2
[ox2:22311] jobid 0
[ox2:22311] procid 2
[ox2:22311] procdir: /tmp/openmpi-sessions-javier@ox2_0/default-universe/0/2
[ox2:22311] jobdir: /tmp/openmpi-sessions-javier@ox2_0/default-universe/0
[ox2:22311] unidir: /tmp/openmpi-sessions-javier@ox2_0/default-universe
[ox2:22311] top: openmpi-sessions-javier@ox2_0
[ox2:22311] tmp: /tmp
[ox2:22400] [0,1,1] setting up session dir with
[ox2:22400] universe default-universe
[ox2:22400] user javier
[ox2:22400] host ox2
[ox2:22400] jobid 1
[ox2:22400] procid 1
[ox2:22400] procdir: /tmp/openmpi-sessions-javier@ox2_0/default-universe/1/1
[ox2:22400] jobdir: /tmp/openmpi-sessions-javier@ox2_0/default-universe/1
[ox2:22400] unidir: /tmp/openmpi-sessions-javier@ox2_0/default-universe
[ox2:22400] top: openmpi-sessions-javier@ox2_0
[ox2:22400] tmp: /tmp
[oxigeno.ugr.es:30067] spawn: in job_state_callback(jobid = 1, state = 0x3)
[oxigeno.ugr.es:30070] orted: job_state_callback(jobid = 1, state = 134601784)
[oxigeno.ugr.es:30067] Info: Setting up debugger process table for applications
[ox2:22311] orted: job_state_callback(jobid = 1, state = 134643904)
MPIR_being_debugged = 0
MPIR_debug_gate = 0
MPIR_debug_state = 1
MPIR_acquired_pre_main = 0
MPIR_i_am_starter = 0
MPIR_proctable_size = 2
MPIR_proctable:
(i, host, exe, pid) = (0, ox2, hello, 22400)
(i, host, exe, pid) = (1, ox0, hello, 30076)
Killed by signal 2.
[oxigeno.ugr.es:30070] sess_dir_finalize: found job session dir empty - deleting
[oxigeno.ugr.es:30070] sess_dir_finalize: univ session dir not empty - leaving
mpirun: killing job...
--------------------------------------------------------------------------
WARNING: A process refused to die!
Host: oxigeno.ugr.es
PID: 30076
This process may still be running and/or consuming resources.
--------------------------------------------------------------------------
[oxigeno.ugr.es:30070] sess_dir_finalize: proc session dir not empty - leaving
[oxigeno.ugr.es:30070] orted: job_state_callback(jobid = 1, state =
ORTE_PROC_STATE_ABORTED)
--------------------------------------------------------------------------
WARNING: A process refused to die!
Host: oxigeno.ugr.es
PID: 30076
This process may still be running and/or consuming resources.
--------------------------------------------------------------------------
--------------------------------------------------------------------------
WARNING: A process refused to die!
Host: oxigeno.ugr.es
PID: 30076
This process may still be running and/or consuming resources.
--------------------------------------------------------------------------
[javier@oxigeno hello]$ exit
Script terminado (Tue Apr 25 11:25:41 2006
)
#include <mpi.h> // for MPI_Init()
#include <stdio.h> // for printf()
#include <stdlib.h> // for exit()
int main(int argc, char **argv){
int rank, size;
MPI_Init(&argc, &argv);
MPI_Comm_rank(MPI_COMM_WORLD, &rank);
MPI_Comm_size(MPI_COMM_WORLD, &size);
printf("Hello, world! I am %d of %d\n", rank, size);
MPI_Finalize();
exit(0);
}
