ANSYS: Computer-aided engineering software

Contents

1. Overview of package
   1. General usage
2. Availability of package by cluster
3. Licensing
4. Using fluent with MPI

Overview of package

General usage information

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 of the package ANSYS, by cluster

This section lists the available versions of the package ANSYSon the different clusters.

Available versions of ANSYS on the Zaratab cluster

Licensing

The ANSYS suite of software is commercially licensed software. It is currently being made available to users of the UMD Deepthought HPC clusters by the generosity of the Dept of Mechanical Engineering.

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 srun hostname -s > $FLUENTNODEFILE command. See the examples below, paying attention to the lines with $FLUENTNODEFILE.

ANSYS launches the processes on the listed nodes via ssh. In order to facilitate the passwordless connection, the RSA keys have to be present in your ~/.ssh directory. If the RSA keys are not present, you will receive an error like "Permission denied (publickey,gssapi-keyex,password)" or "No cached password provided". Please follow the instructions to create the intracluster RSA key pair.

If you are using csh or tcsh, create a submission script similar to:

#!/bin/tcsh
#SBATCH --ntasks=64
#SBATCH -t 20:00:00
#SBATCH --mem-per-cpu=6000

module load ansys

#Get an unique temporary filename to use for our nodelist
set 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
fluent 3ddp -g -t $SLURM_NTASKS -mpi=intel -ssh -cnf="$FLUENTNODEFILE" -i YOUR_JOU_FILE

#Clean up
rm $FLUENTNODEFILE

If you use the bourne or bourne again shells:

#!/bin/bash
#SBATCH --ntasks=64
#SBATCH -t 20:00:00
#SBATCH --mem-per-cpu=6000

#Get our profile
. ~/.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
fluent 3ddp -g -t $SLURM_NTASKS -mpi=intel -ssh -cnf="$FLUENTNODEFILE" -i YOUR_JOU_FILE

#Clean up
rm $FLUENTNODEFILE

Using ANSYS in graphical mode

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

You may run ANSYS in graphical mode using the OnDemand Interactive Desktop: start and connect to the desktop, then open a terminal window, run module load ansys and start the ANSYS application.