ANSYS Mechanical

To load the default version of ANSYS module, use  module load ansys . To select a particular software version, use   module load ansys/version . For example, use  module load ansys/17.2   to load ANSYS version 17.2. 

Following a successful loading of the ANSYS module, you can access the ANSYS Mechanical commands and utility programs located in your execution path:

ansys <switch options> <file>

The ANSYS Mechanical command takes a number of Unix-style switches and parameters.

The -j Switch

The command accepts a -j switch. It specifies the "job id," which determines the naming of output files. The default is the name of the input file.

The -d Switch

The command accepts a -d switch. It specifies the device type. The value can be X11, x11, X11C, x11c, or 3D.

The -m Switch

The command accepts a -m switch. It specifies the amount of working storage obtained from the system. The units are megawords.

The memory requirement for the entire execution will be approximately 5300000 words more than the -m specification. This is calculated for you if you use ansnqs to construct an NQS request.

The -b [nolist] Switch

The command accepts a -b switch. It specifies that no user input is expected (batch execution).

The -s [noread] Switch

The command accepts a -s switch. By default, the start-up file is read during an interactive session and not read during batch execution. These defaults may be changed with the -s command line argument. The noread option of the -s argument specifies that the start-up file is not to be read, even during an interactive session. Conversely, the -s argument with the -b batch argument forces the reading of the start-up file during batch execution.

The -g [off] Switch

The command accepts a -g switch. It specifies that the ANSYS graphical user interface started automatically.

ANSYS Mechanical parameters

ANSYS Mechanical parameters may be assigned values on the command. The parameter must be at least two characters long and must be a legal parameter name. The ANSYS Mechanical parameter that is to be assigned a value should be given on the command line with a preceding dash (-), a space immediately after, and the value immediately after the space:

module load ansys
ansys -pval1 -10.2 -EEE .1e6
sets pval1 to -10.2 and EEE to 100000

When you log into cardinal.osc.edu you are actually logged into a linux box referred to as the login node. To gain access to the mutiple processors in the computing environment, you must submit your ANSYS Mechanical analysis to the batch system for execution. Batch jobs can request mutiple nodes/cores and compute time up to the limits of the OSC systems. Refer to Batch Limit Rules for more info. Batch jobs run on the compute nodes of the system and not on the login node. It is desirable for big problems since more resources can be used.

Interactive Batch Session

Interactive mode is similar to running ANSYS Mechanical on a desktop machine in that the graphical user interface will be sent from OSC and displayed on the local machine. Interactive jobs are run on compute nodes of the cluster, by turning on X11 forwarding. The intention is that users can run ANSYS Mechanical interactively for the purpose of building their model and preparing their input file. Once developed this input file can then be run in no-interactive batch mode.

To run interactive ANSYS Mechanical, a batch job need to be submitted from the login node, to request necessary compute resources, with X11 forwarding. For example, the following command requests one core ( -N 1 -n 1  ), for a walltime of 1 hour (  -t 1:00:00 ), with one ANSYS license:

sinteractive -N 1 -n 1 -t 1:00:00 -L ansys@osc:1,ansyspar@osc:24 -A <account>

You may adjust the numbers per your need. This job will queue until resources becomes available. Once the job is started, you're automatically logged in on the compute node; and you can launch ANSYS Mechanical and start the graphic interface with the following commands:

module load ansys
ansys -g

Non-interactive Batch Job (Serial Run)

A batch script can be created and submitted for a serial or parallel run. You can create the batch script using any text editor you like in a working directory on the system of your choice. For a given model, prepare the input file with ANSYS Mechanical commands (named  ansys.in  for example) for the batch run. Below is the example batch script (   job.txt ) for a serial run:

#!/bin/bash
#SBATCH --job-name=ansys_test
#SBATCH --time=1:00:00
#SBATCH --nodes=1 --ntasks-per-node=1
#SBATCH -L ansys@osc:1
#SBATCH --account=<account>

cd $TMPDIR  
cp $SLURM_SUBMIT_DIR/ansys.in .    
module load ansys  
ansys < ansys.in   
cp <output files> $SLURM_SUBMIT_DIR

In order to run it via the batch system, submit the  job.txt  file with the command:  qsub job.txt .

Non-interactive Batch Job (Parallel Run)

To take advantage of the powerful compute resources at OSC, you may choose to run distributed ANSYS Mechanical for large problems. Multiple nodes and cores can be requested to accelerate the solution time. Note that you'll need to change your batch script slightly for distributed runs.

For distributed ANSYS Mechanical jobs, the number of processors needs to be specified in the command line with options '-dis -np':

#!/bin/bash
#SBATCH --job-name=ansys_test
#SBATCH --time=1:00:00
#SBATCH --nodes=1 --ntasks-per-node=28
#SBATCH --account=<account>
#SBATCH -L ansys@osc:1,ansyspar@osc:24

...
ansys -b -dis -mpi ibmmpi -np ${SLURM_NTASKS} -i ansys.in
 
...

Notice that in the script above, the ansys parallel license is requested as well as ansys license in the format of

#SBATCH -L ansys@osc:1,ansyspar@osc:n

where n=m-4, with m being the total cpus called for this job. This part is necessary when the total cpus called is greater than 4 (m>4), which applies for the parallel example below as well.

The following shows changes in the batch script if 2 nodes on Cardinal are requested for a parallel ANSYS Mechanical job:

#!/bin/bash
#SBATCH --job-name=ansys_test
#SBATCH --time=3:00:00
#SBATCH --nodes=2 --ntasks-per-node=28
#SBATCH -L ansys@osc:1,ansyspar@osc:52

...
ansys -b -dis -mpi ibmmpi -np ${SLURM_NTASKS} -i ansys.in 
...
pbsdcp -g '<output files>' $SLURM_SUBMIT_DIR

The 'pbsdcp -g' command in the last line in the script above makes sure that all result files generated by different compute nodes are copied back to the work directory.