Smart Job Submission Tool for Fluent Simulations
Wang Junhong, NUS Information Technology
With the recent change of ANSYS Fluent software academic licensing by the developer in early 2021, more parallel Fluent simulations can be supported with the existing academic license in the HPC system. It means more CPU cores can be used to run a Fluent simulation job if needed. To fully benefit from this and also to make optimal use of the hardware computing resources, the automated job submission tool “fluent-job” is revamped to allow more CPU cores to run a Fluent simulation. At the same time, it is also improved with a smart suggestion on the best queue to shorten the waiting time. The likely waiting time in every queue is evaluated using artificial intelligence (AI) analysis based on existing running jobs, the demand and the supply in the queue. With this, users can choose the best queue for the simulation by comparing the benefit between using more CPU cores and shorter waiting time to run the simulation.
On the Atlas HPC cluster, the batch job submission using the updated “fluent-job” is illustrated below. As an end user, you only need to provide the relevant information regarding the Fluent simulation, such as the version of solver to run, the dimension of your simulation, the input script file name and the number of CPU cores you wish to request for the simulation. The rest of the job submission will be taken care by the “fluent-job” tool, reducing the need to remember unrelated information.
# fluent-job
1. Version of Fluent Solver (2020R2, or latest 2021R1?),
Enter the version or press Enter to choose the latest version: 2021R1
2. Dimension of the Simulation (2d, 2ddp, 3d or 3ddp): 3ddp
3. Input Script File for Fluent Simulation: run_case1.txt
4. Suggested No. of CPU Cores for the Simulation (1/12/20/24)
No. of CPU of Queue Estimated Waiting Time
1 *
12 **
20 ****
24 ******
Enter the No. of CPU Cores for the Simulation: 12
Summary of your Fluent Simulation Job:
1. Fluent Solver to run: 2021R1
2. Dimension of the Simulation: 3ddp
3. Input Script File: run_case1.txt
4. No. of CPU Cores to Run: 12
5. Batch Job Output Log File: STDOUT.o*
6. Expected Waiting Time in the Queue: **
Proceed to Submit This Job (Yes/No/Quit): Y
This Job is submitted as (# qstat -aw):
Users are also encouraged to use the HPC Cloud cluster via the login node hpclogin, as additional HPC resources are provided in Cloud. The job submission will be simpler as there is only one queue. Most of Fluent simulations suggested to run a simulation using 16 CPU cores as default on the Cloud cluster. However, you can choose to use either 1 CPU core because of the constraint of simulation modeling or up to 32 cores if you can justify the requirements.
# fluent-job
1. Version of Fluent Solver (2020R2, or latest 2021R1?),
Enter the version or press Enter to choose the latest version: 2021R1
2. Dimension of the Simulation (2d, 2ddp, 3d or 3ddp): 3ddp
3. Input Script File for Fluent Simulation: run_case1.txt
4. Suggested No. of CPU Cores for the Simulation (1/12/20/24)
Enter the No. of CPU Cores for the Simulation: 16
Summary of your Fluent Simulation Job:
1. Fluent Solver to run: 2021R1
2. Dimension of the Simulation: 3ddp
3. Input Script File: run_case1.txt
4. No. of CPU Cores to Run: 16
5. Batch Job Output Log File: STDOUT.o*
6. Expected Waiting Time in the Queue: **
Proceed to Submit This Job (Yes/No/Quit): Y
This Job is submitted as (# qstat -aw):
In addition, a function for the printing of sample input script for Fluent simulation is also enabled in the “fluent-job” tool. This will help users list out the sample script on the HPC system and then copy and modify it for their own simulation job.
The sample input script for both steady-state and unsteady-state simulation can be listed out on the HPC system as illustrated below.
# fluent-job -script
---------------------------------------------------------
Fluent sample script for Steady-State Flow Simulation:
---------------------------------------------------------
/file/read-case test.cas
/file/read-data test.cas
/file/cff-files no
/solve/iterate 100
/file/write-data test_100.dat
yes
exit
yes
-----------------------------------------------------------
Fluent sample script for Unsteady-State Flow Simulation:
-----------------------------------------------------------
/file/read-case test2.cas
/file/read-case test2_00000.cas
/file/cff-files no
/file/autosave/data-frequency 100
/solve/set/time-step 0.1
/solve/dual-time-iterate 1000 20
/file/write-case test2_new.cas
yes
/file/write-data test2_new.dat
yes
exit
yes
