Learning Forum

[abhijitrk]

Hello Everyone,

I am runnig LS-Dyna through ANSYS Product Launcher. Recentrly I tried to run some simulations using MPP version of ANSYS LS-Dyna but the files do terminate in error. However, when I run the same files using my workstation, file runs and provide good results (though the run time is in number of days). I do not understand why same file running on workstation run well while files running on MPP version terminate.

Is there anything else I have to request in the keyword file of LS-Dyna?

 

Best Regards

Abhijit

[tsiriaks]

Hi Abhijit,

Could you post the screenshot of the error ?

I'm a bit confused, it sounds like you are talking about two machines and compare analysis mode with a computer.

On your workstation, what if you run with MPP ?

Also, on the other machine, what if you run in serial mode or SMP ?

If you only talk about one machine but just different behaviors because of different analysis modes, then there might be issue with security software on your machine blocking multiple processes used by MPP mode.

Thanks,

Win

[abhijitrk]

Hi Win I will upload the screenshot tomorrow.
On my workstation I am running SMP version I guess, there is no MPP version of ansys ls-dyna installed on the workstation. The workstation has 6 processors. I am running few simulations that involve quasi static loading on reinforced UHPC concrete beams. I am using implicit analysis.

I do not have any trouble with explicit analysis on HPC using MPP version of ansys ls-dyna (tried 2-3 imapt simulations).

The implicit analysis models I have built run fine on the workstation, however, it takes longer to complete an analysis, and, that is the sole reason I moved to the MPP capabilities using my university's HPC facility.

I am utilizing 16-24 processors on HPC facility. The facility has correct version of ansys ls-dyna licenses installed although I am not sure whether they have correct mpi files installed (MPI files are required only when MPP is requested).
Anyways, the implicit analysis models don't terminate normally. In some cases errors are like "NaN on processor 1,2 or n etc". Some terminate because of internal model error like "negative volume on elemnent xyz".

But my point is if a file runs on workstation (SMP) using the same version of ansys ls-dyna those shold run on HPC(mpp) facilities right?
Let me know what are your thoughts about this and what will be the best way to resolve this issue.

I am using ls-dyna through ansys, and LS - dyna (LSTC) do not support students. The University is licensed through ansys, and in addition, ansys do not entertain students either.
Looking for some guidance and thanks in advance.
Best Regards
Abhijit

[tsiriaks]

Hi Abhijit,

There are lots of things that can go wrong when you change machine even though it's the same project. Sometimes, even on the same machine, you can have issue with MPP while SMP is solving fine, this is caused by the reason I said earlier. 

Are you saying that on this cluster, you can solve ANSYS LS-Dyna with MPP and explicit analysis just fine but you have issue if you are solving ANSYS LS-Dyna with MPP and implicit analysis  ?

I have to see the full error message that you get from the cluster.

Also, what is the OS version on the cluster ?

Thanks,

Win

 

[abhijitrk]

Hi Win,

This is one type of error I see in implicit analysis. 

Are you saying that on this cluster, you can solve ANSYS LS-Dyna with MPP and explicit analysis just fine but you have issue if you are solving ANSYS LS-Dyna with MPP and implicit analysis  ?

Yes, correct.

Also, what is the OS version on the cluster ?

It is linux based. I do not know much about the version though.

Thanks

Abhijit

 

[abhijitrk]

Hi Win,

Please find additional screenshot of the error.

[tsiriaks]

Hi Abhijit,

I've pinged a Mechanical support engineer to look into this. I will follow up with him again tomorrow.

Thanks,

Win

[abhijitrk]

Thanks Win. Appreaciate your help.