ANSYS: Computer-aided engineering software

Overview of package

Package:	ANSYS
Description:	Computer-aided engineering software
For more information:	http://www.ansys.com
Categories:	Engineering
License:	Proprietary

General Usage

Ansys is a suite of software for engineering analysis over a range of disciplines, including finite element analysis, structural analysis, and fluid dynamics.

IMPORTANT NOTE: Ansys works with openMPI, use flag: -mpi=openmpi

                NOTE

This is restrictively licensed software. It is currently being made available on the UMD HPC clusters by the generosity of the Dept of Mechanical Engineering.

Available versions by cluster

This section lists the available versions of the package ANSYSon the UMD HPC clusters.

Versions available on the Zaratan cluster

Version	Module tags	CPU(s) optimized for	GPU ready?
23.1	23.1	x86_64	Yes
21.2	21.2	x86_64	Yes

Using fluent with MPI

To make use of the fluent package within the ANSYS suite in a parallel fashion with a job spanning multiple nodes, you need to provide special arguments to the fluent command. In particular, you would want to provide the arguments:

g : to instruct fluent not to use a graphical environment
-t $SLURM_NTASKS : to start the number of tasks requested of Slurm
-mpi=intel : to ensure the correct MPI libraries are used
-cnf=NODEFILE : to tell fluent which nodes to use

In the -cnf argument, you need to provide the name of a file containing a list of the nodes to use. This can be done using the command srun hostname -s > $FLUENTNODEFILE

ANSYS launches the processes on the listed nodes via the ssh command, so you need to set up RSA public key authentication among the nodes in the cluster to allow passwordless ssh connections between the nodes of the cluster. If this is not set up properly, you will likely receive an error like "Permission denied (publickey,gssapi-keyex,password)" or "No cached password provided". If you get one of these or a similar connection error, please follow the instructions to setup public key authentication among the cluster nodes.

You can use a job script like:

#!/bin/bash
#SBATCH --ntasks=64 #Change this to the appropriate number of MPI tasks
#SBATCH -t 20:00:00 #Change this to an appropriate time limit
#SBATCH --mem-per-cpu=4000 #Change this to the appropriate amoung of memory

# Get our profile
source /etc/profile

module load ansys

# Get an unique temporary filename to use for our nodelist
FLUENTNODEFILE=$(mktemp)

# Output the nodes to our nodelist file, repeating nodes
# according to number of tasks on that node
srun hostname -s > $FLUENTNODEFILE

# Display to us the nodes being used
echo "Running on nodes:"
cat $FLUENTNODEFILE

# Run fluent with the requested number of tasks on the assigned nodes
# Replace YOUR_JOU_FILE with the name of your journal file
fluent 3ddp -g -t $SLURM_NTASKS -mpi=intel -ssh -cnf="$FLUENTNODEFILE" -i YOUR_BJOU_FILE

# Clean up
rm $FLUENTNODEFILE

Using ANSYS in graphical mode

It is recommended to run ANSYS applications in batch mode. Do not try to run GUI-based ANSYS applications on the login nodes of the HPC clusters since they typically use many resources and therefore may adversely impact other users. Also, the remote connection may prevent or slow down the GUI display on your monitor.

You may run ANSYS in graphical mode using the interactive desktop applet of the OnDemand Web Portal. This will start a job on the cluster which presents a full graphical desktop to you through your web browser. You can then open a terminal window, issue the module load ansys and start the ANSYS application. As the desktop is running on a compute node and not a login node, you are allowed to perform computationally intensive tasks.