Rocky Python MPI Hello World - Revision history

Jondale at 20:35, 12 January 2026

2026-01-12T20:35:32Z

← Older revision		Revision as of 20:35, 12 January 2026
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	</syntaxhighlight>		</syntaxhighlight>

	With the above given information we are going to use ~~<code>OpenMPI/5.0.8-GCC-14.3.0</code> and~~ <code>mpi4py/4.0.1</code>.		With the above given information we are going to use <code>mpi4py/4.0.1</code>.


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	#SBATCH --time=00:05:00		#SBATCH --time=00:05:00

	~~module load OpenMPI/5.0.8-GCC-14.3.0~~
	module load mpi4py/4.0.1		module load mpi4py/4.0.1

Jondale at 20:35, 12 January 2026

2026-01-12T20:35:02Z

@@ Line 5: / Line 5: @@
 Rocky supports PMIx v3 for MPI process management. MPI applications should be launched via srun using --mpi=pmix_v3.
-To see what versions of OpenMPI are available use the following command:
+To see what versions of mpi4py are available use the following command:
 <syntaxhighlight lang="bash">

Jondale at 19:15, 12 January 2026

2026-01-12T19:15:09Z

← Older revision		Revision as of 19:15, 12 January 2026
Line 74:		Line 74:
	== hello_mpi4py.sbatch ==		== hello_mpi4py.sbatch ==

			Note the usage of <code>--mpi=pmix_v3</code> parameter.
	<syntaxhighlight lang="bash">		<syntaxhighlight lang="bash">
	#!/usr/bin/env bash		#!/usr/bin/env bash

Jondale at 19:08, 12 January 2026

2026-01-12T19:08:10Z

@@ Line 1: / Line 1: @@
 = MPI4PY Jobs on Rocky =
-== Supported Stack ==
+== Supported versions ==
-We currently recommend and support:
+Rocky supports PMIx v3 for MPI process management. MPI applications should be launched via srun using --mpi=pmix_v3.
-* '''OpenMPI 4.1.6'''
+To see what versions of OpenMPI are available use the following command:
-= MPI4PY Example: Hello World in Python =
+<syntaxhighlight lang="bash">
@@ Line 37: / Line 83: @@
 #SBATCH --time=00:05:00
-module load OpenMPI/4.1.6-GCC-13.2.0
+module load OpenMPI/5.0.8-GCC-14.3.0
 module load mpi4py/4.0.1

Jondale at 14:22, 16 December 2025

2025-12-16T14:22:55Z

← Older revision		Revision as of 14:22, 16 December 2025
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	= ~~MPI~~ Jobs on Rocky =		= MPI4PY Jobs on Rocky =

	== Supported Stack ==		== Supported Stack ==
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	* '''mpi4py 4.0.1'''		* '''mpi4py 4.0.1'''

	= ~~MPI~~ Example: Hello World in Python =		= MPI4PY Example: Hello World in Python =

Jondale at 14:21, 16 December 2025

2025-12-16T14:21:56Z

← Older revision		Revision as of 14:21, 16 December 2025
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	module load OpenMPI/4.1.6-GCC-13.2.0		module load OpenMPI/4.1.6-GCC-13.2.0
	module load mpi4py		module load mpi4py/4.0.1

	srun --mpi=pmix_v3 python hello_mpi4py.py		srun --mpi=pmix_v3 python hello_mpi4py.py

Jondale at 14:19, 16 December 2025

2025-12-16T14:19:19Z

← Older revision		Revision as of 14:19, 16 December 2025
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	#SBATCH --error=hello-mpi4py-%j.err		#SBATCH --error=hello-mpi4py-%j.err
	#SBATCH --nodes=2		#SBATCH --nodes=2
	#SBATCH --ntasks=3		#SBATCH --ntasks=8
	#SBATCH --time=00:05:00		#SBATCH --time=00:05:00

Jondale at 14:18, 16 December 2025

2025-12-16T14:18:49Z

← Older revision		Revision as of 14:18, 16 December 2025
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	#SBATCH --output=hello-mpi4py-%j.out		#SBATCH --output=hello-mpi4py-%j.out
	#SBATCH --error=hello-mpi4py-%j.err		#SBATCH --error=hello-mpi4py-%j.err
	#SBATCH --nodes=1		#SBATCH --nodes=2
	#SBATCH --ntasks=3		#SBATCH --ntasks=3
	#SBATCH --time=00:05:00		#SBATCH --time=00:05:00
	~~#SBATCH --partition=kivlin,compute_all~~

	module load OpenMPI/4.1.6-GCC-13.2.0		module load OpenMPI/4.1.6-GCC-13.2.0
	module load mpi4py		module load mpi4py

	~~echo "=== Running mpi4py test with Slurm PMIx ==="~~
	srun --mpi=pmix_v3 python hello_mpi4py.py		srun --mpi=pmix_v3 python hello_mpi4py.py
	</syntaxhighlight>		</syntaxhighlight>

Jondale: Created page with "= MPI Jobs on Rocky = == Supported Stack == We currently recommend and support: * '''OpenMPI 4.1.6''' * '''PMIx 4.2.6''' * '''mpi4py 4.0.1''' = MPI Example: Hello World in Python = == hello_mpi4py.py == from mpi4py import MPI import socket comm = MPI.COMM_WORLD rank = comm.Get_rank() size = comm.Get_size() hostname = socket.gethostname() print(f"Hello from rank {rank} of {size} on {hostname}") == hello_mpi4py.s..."

2025-12-16T14:17:24Z

Created page with "= MPI Jobs on Rocky = == Supported Stack == We currently recommend and support: * '''OpenMPI 4.1.6''' * '''PMIx 4.2.6''' * '''mpi4py 4.0.1''' = MPI Example: Hello World in Python = == hello_mpi4py.py == <syntaxhighlight lang="python"> from mpi4py import MPI import socket comm = MPI.COMM_WORLD rank = comm.Get_rank() size = comm.Get_size() hostname = socket.gethostname() print(f"Hello from rank {rank} of {size} on {hostname}") </syntaxhighlight> == hello_mpi4py.s..."

New page

= MPI Jobs on Rocky =

== Supported Stack ==

We currently recommend and support:

* '''OpenMPI 4.1.6'''
* '''PMIx 4.2.6'''
* '''mpi4py 4.0.1'''

= MPI Example: Hello World in Python =

== hello_mpi4py.py ==

<syntaxhighlight lang="python">
from mpi4py import MPI
import socket

comm = MPI.COMM_WORLD
rank = comm.Get_rank()
size = comm.Get_size()
hostname = socket.gethostname()

print(f"Hello from rank {rank} of {size} on {hostname}")
</syntaxhighlight>

== hello_mpi4py.sbatch ==

<syntaxhighlight lang="bash">
#!/usr/bin/env bash
#SBATCH --job-name=hello-mpi4py
#SBATCH --output=hello-mpi4py-%j.out
#SBATCH --error=hello-mpi4py-%j.err
#SBATCH --nodes=1
#SBATCH --ntasks=3
#SBATCH --time=00:05:00
#SBATCH --partition=kivlin,compute_all

module load OpenMPI/4.1.6-GCC-13.2.0
module load mpi4py

echo "=== Running mpi4py test with Slurm PMIx ==="
srun --mpi=pmix_v3 python hello_mpi4py.py
</syntaxhighlight>

Submit the job:

<pre>
sbatch hello_mpi4py.sbatch
</pre>

== Expected Output ==

<pre>
Hello from rank 0 of 8 on rocky4.rocky.nimbios.org
Hello from rank 1 of 8 on rocky4.rocky.nimbios.org
Hello from rank 2 of 8 on rocky4.rocky.nimbios.org
Hello from rank 3 of 8 on rocky4.rocky.nimbios.org
Hello from rank 4 of 8 on rocky5.rocky.nimbios.org
Hello from rank 5 of 8 on rocky5.rocky.nimbios.org
Hello from rank 6 of 8 on rocky5.rocky.nimbios.org
Hello from rank 7 of 8 on rocky5.rocky.nimbios.org
</pre>