Runing multiple instances of Ansys Mechanical ...

[vigardo]

Dear experts,

I need to speed up the solution of a large list of Ansys Mechanical (14.5) jobs, typically more than 50000. Such analyses are performed by a perl script that runs each job in batch mode. Since my system size is small and the typical execution time of the jobs is between 1 and 10 seconds, the speedups attained by varying the number of processors from 1 to 4 with the "-np" option is very small, i.e. 10-20% only. As a workaround I tried to split the job list in two and run each part in different terminals, but unfortunately Ansys crashes.

Is it possible to run several instances of Ansys Mechanical in Windows or Linux at the same time? How?

This is the command I use for Windows, is it ok?
##> "<MY_ANSYS_PATH>\ansys145.exe" -p ansys -dir <MY_WORK_DIRECTORY> -j [JOB_NAME] -s noread -l en-us -b nolist -np 2 -i <INPUT_FILE> -o <OUTPUT_FILE>

Thanks a lot!

 

[vigardo]

I also tried to run two different jobs at the same time in different terminals that used a different working directory. Unforutnately one of them crashes (windows alerts that Ansys stopped working) while the other finishes normally. Note that to avoid Ansys-lock-related problems I set the Ansys´ environment variable ANSYS_LOCK to OFF (Ansys help says that by default ANSYS_LOCK=ON to create file locks that prevent users from opening a new job with the same name and in the same directory as the current job).

These were the new commands tested:

command_A#> "<MY_ANSYS_PATH>\ANSYS145.exe" -p ansys -dir "<WORK_DIR_A>" -j job_A -s noread -l en-us -b nolist -np 1 -m 512 -db 256 -i my_job_A.txt -o my_job_A.out

commandB#> "<MY_ANSYS_PATH>\ANSYS145.exe" -p ansys -dir "<WORK_DIR_B>" -j job_B -s noread -l en-us -b nolist -np 1 -m 512 -db 256 -i my_job_B.txt -o my_job_B.out

Any suggestion? I really don´t know what to do next... Thanks!

 

[vigardo]

Problem was solved. It is possible to run N instances of Ansys Mechanical at the same time to speed up calculations as long as you have N licenses.

The problem was that I made a mistake: both input files (my_job_A.txt and my_job_B.txt) used the same working directory. There was a CWD ansys command in the input files that overrode the "-dir" option of the input command at some point and caused an input/output error, wich was evidenced in .err file. This was the ansys command: /CWD,'<C:<SOME_DIRECTORY_NAME>\test\ansys1'

Thanks a lot anyways!