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ANSYS

ANSYS offers a comprehensive software suite that spans the entire range of physics, providing access to virtually any field of engineering simulation that a design process requires.

Available versions of ANSYS at ULHPC

You can check the available versions of ANSYS at ULHPC with the command module spider ansys.

$ module spider ansys

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  tools/ANSYS:
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    Description:
      ANSYS simulation software enables organizations to confidently predict how their products will operate in the real world. We believe that every product is a promise of something greater. 

     Versions:
        tools/ANSYS/21.1
        tools/ANSYS/2022R2
        tools/ANSYS/2024R2

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  For detailed information about a specific "tools/ANSYS" package (including how to load the modules) use the module's full name.
  Note that names that have a trailing (E) are extensions provided by other modules.
  For example:

     $ module spider tools/ANSYS/2024R2
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According to the output of the module command, there are 3 versions of ANSYS available, and 2024R2 is the latest.

Working in interactive mode

To open an ANSYS in interactive mode, connect to the cluster with X11 forwarding enabled,

# From your local computer
$ ssh -X iris-cluster

# From your local computer
$ ssh -X aion-cluster

and then create and allocation with X11 forwarding enabled:

# Reserve the node for interactive computation
$ salloc --partition=interactive --qos=debug --time=02:00:00 --ntasks=1 --cpus-per-task=14 --x11

# Load the required version of ANSYS and needed environment
$ module purge
$ module load tools/ANSYS/2024R2

# To launch ANSYS workbench
$ runwb2

# Reserve the node for interactive computation
$ salloc --partition=interactive --qos=debug --time=02:00:00 --ntasks=1 --cpus-per-task=16 --x11

# Load the required version of ANSYS and needed environment
$ module purge
$ module load tools/ANSYS/2024R2

# To launch ANSYS workbench
$ runwb2

In this example the number of cpus is selected so that a single full socket is reserved in each cluster.

Submitting batch scripts

When you run ANSYS packages such as Fluent in batch mode apart from the usual input, such as journal files, you may provide options to execute the computation across multiple compute nodes.

According to the output of help function of Fluent, fluent -h,

  • -gu runs the software without GUI,
  • -cnf specifies the host file with the list of hosts available to the program,
  • -t specifies the number of host from the host file that will be used (only -t<number> notation is supported for this flag),
  • -mpi selects the MPI backend, and
  • -p selects the interconnect (only -p<interconnect> notation is supported for this flag).
#!/usr/bin/bash --login
#SBATCH --job-name=VOF
#SBATCH --mail-type=end,fail
#SBATCH --mail-user=name.surname@uni.lu
#SBATCH --partition=batch
#SBATCH --qos=normal
#SBATCH --nodes=4
#SBATCH --ntasks-per-node=28
#SBATCH --cpus-per-task=1
#SBATCH --exclusive
#SBATCH --time=1-00:00:00
#SBATCH --output=%x-%j.out
#SBATCH --error=%x-%j.err

declare HOSTSFILE=/tmp/hostlist-${SLURM_JOB_ID}
scontrol show hostnames > ${HOSTSFILE}

# To get basic info. about the job
echo "== Job ID: ${SLURM_JOBID}"
echo "== Node list: ${SLURM_NODELIST}"
echo "== Working directory: ${SLURM_SUBMIT_DIR}"
echo "Starting run at $(date)"
echo ""

module purge
module load tools/ANSYS/2024R2

fluent 3ddp -gu -t${SLURM_NTASKS} -cnf=${HOSTSFILE} -mpi=openmpi -pib -i journal.txt 

#!/usr/bin/bash --login
#SBATCH --job-name=VOF
#SBATCH --mail-type=end,fail
#SBATCH --mail-user=name.surname@uni.lu
#SBATCH --partition=batch
#SBATCH --qos=normal
#SBATCH --nodes=4
#SBATCH --ntasks-per-node=128
#SBATCH --cpus-per-task=1
#SBATCH --exclusive
#SBATCH --time=1-00:00:00
#SBATCH --output=%x-%j.out
#SBATCH --error=%x-%j.err

declare HOSTSFILE=/tmp/hostlist-${SLURM_JOB_ID}
scontrol show hostnames > ${HOSTSFILE}

# To get basic info. about the job
echo "== Job ID: ${SLURM_JOBID}"
echo "== Node list: ${SLURM_NODELIST}"
echo "== Working directory: ${SLURM_SUBMIT_DIR}"
echo "Starting run at $(date)"
echo ""

module purge
module load tools/ANSYS/2024R2

fluent 3ddp -gu -t${SLURM_NTASKS} -cnf=${HOSTSFILE} -mpi=openmpi -pib -i journal.txt

The ANSYS binaries come bundled with their own version of MPI that operates independent of the system job launcher and so they need a host list and a communication backend to start the job. This job

  • runs SLURM_NTASKS tasks (-t${SLURM_NTASKS}), where SLURM_NTASKS = SLURM_NTASKS_PER_NODE * SLURM_JOB_NUM_NODES are assigned in a round-robin fashion along the entries of HOSTFILE, and
  • uses the openmpi backend (-mpi=openmpi)
  • with the ib (Infiniband) interconnect (-pid).

Similar options are used for other packages of ANSYS.

Additional information

ANSYS provides the customer support, if you have a license key, you should be able to get access the support, manuals, and other useful documents.

You can find an old but relevant version of the user manual section on parallel jobs in the documentation of the ENEAGRID/CRESCO hyper cluster. The user manual provides detailed explanation for the various parallel job options.

Tip

If you find some issues with the instructions above, please file a support ticket.

Last update: December 2, 2024