Using StarCCM+ at the UB CCR

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1 Using StarCCM+ at the UB CCR About This Document This document provides a step-by-step tutorial for using the StarCCM + graphical user interface (GUI) on the UB CCR cluster and viz node front-end. It also demonstrates how to load and solve StarCCM simulations in parallel on CCR compute nodes from within the GUI. Why would I want to run StarCCM+? StarCCM+ is a convenient way to develop a model. It also allows for monitoring solution progress and making sure a new model has been developed correctly. A user can run an intermediate version of their model (e.g. after adding new components) and check to see if the new addition looks to be working ok. If problems are observed, the user can halt the model via the GUI and make changes as needed. Why wouldn t I want to run StarCCM+? StarCCM+ isn t appropriate for production -style model runs where user interaction isn t necessary. These are model runs or parameter sweeps for which the user is already very confident in the model that they have developed. Basically, if you are finished with model development and just need to run a complex model or parameter sweep, then running StarCCM+ on the cluster is not appropriate. Instead, you should use the sbatch command to submit a SLURM job that will run StarCCM in batch mode. Example scripts are available on the rush front-end: /util/slurm-scripts/slurm-starccm-single-node (for single-node shared memory parallelism) /util/slurm-scripts/slurm-starccm-multi-node (for multi-node distributed memory parallelism) How do I use StarCCM+ at UB CCR? There are several steps involved. First, users should become familiar with logging into the UB CCR viz node front-end machine (viz01.ccr.buffalo.edu). Instructions for this are given below in Step 1 (Install nice client and login to viz node). Step 1 Connecting to the CCR viz node The CCR viz node and accompanying client software allows users to remotely run graphics intensive software without experiencing sluggishness and degraded functionality associated with typical remote connection approaches, such as XWin32. To use the viz node you must connect to it via the following web-site using your favorite browser. If prompted, choose to accept certificates, add exception, continue anyway, understand the risks, etc.

2 Click on the Log-in link located on the left-hand site of the web-site it is circled in red in the above image. Enter your login information when prompted it s the same as your CCR login. Step 2 Installing viz node client software Note: this step only needs to be performed once. In the area under You will need to update your DCV plugin select the client installer appropriate for your machine and run it. Step 3 Launching a Linux desktop Once the viz node client software is installed you can launch a 3D Linux desktop session from the website. Click Desktop sessions 3D Linux Session on the left-hand side of the web-site. Select autodetect resolution unless you are confident that one of the other resolution alternatives matches your system. Then click Start. At this point the Session area of the site may display something cryptic like the following: This message is normal shortly after it appears your browser will prompt you to open the client session. In Internet Explorer, look for a dialog window like the one below and choose Open as shown in the image below. In FireFox, look for a dialog like the one below and choose Ok to open using the VNC viewer that was installed previously. A new VNC window will appear containing the desktop, as shown below. In the Server Status dialog click Close to dismiss the 32-bit application warning.

3 Step 3 Launching the DCV Monitor [optional] The DCV monitor is a useful tool for keeping track of the performance of the remote visualization client and adjusting settings as needed to improve responsiveness. To launch the monitor press CTRL + SHIFT + F9 from within the remote desktop. The following floating console window will appear: Click on the Advanced option of the DCV Console and enable the Show frames per second option. This will cause each graphics window to report its display rate in the lower right hand corner. For example, consider the DCV demo window shown below.

4 Rates less than 24 fps indicate degraded responsiveness which can be improved by reducing quality using the slider in the DCV Console, as shown below. Step 4 Running StarCCM+ from the viz node In the Desktop menu bar click Applications System Tools Terminal as shown below to launch a Linux terminal. You will now use SLURM to request compute nodes for loading and running a StarCCM model. A machine file will be created once the nodes are allocated. The machine file will inform StarCCM+ of the nodes to use when loading and solving the model. Type the following in the terminal shell: $ module load stubl (load tools and utilities for SLURM) $ cd WORKDIR (replace WORKDIR with path to the folder containing your simulation file) $ fisbatch --nodes=2 --ntasks-per-node=12 --time=01:00:00 (request 2 SLURM nodes for 1 hour) FISBATCH -- waiting for JOBID ###### to start on cluster=????? and partition=????...! FISBATCH -- Connecting to head node (??????) $ srun hostname sort > machinefile (creates a machine file) $ module load starccm/9.04 (replace 9.04 with desired version) $ starccm+ & StarCCM+ will now launch and be accessible to you remotely via the viz node. The next steps will illustrate loading and running a StarCCM model using this GUI and the CCR compute nodes.

5 Step 5 Load a simulation In StarCCM+, click File Load Simulation to open the Load Simulation dialog. Choose Parallel Specified by Machine File and use the browser button to navigate to the machine file created in Step 4 (see above). Use the file browser further down in the Load Simulation dialog to navigate to your simulation file. When you are done, click the ok button. StarCCM will now display a bunch of updates in the Output tab at the bottom of the GUI. When the load is completed, the Simulation area of the GUI will be populated with information loaded from your simulation file. (Simulation Area) (Progress Updates)

6 Step 6 Launch a simulation To run the simulation, click on the run simulation icon ( ) or press CTRL+R. The compute nodes reserved using the fisbatch command will be used to run the simulation and the simulation progress will be updated in the StarCCM+ GUI.