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Error Delwaq2 by increasing the number of Processors

GS
Gholamreza Shiravani, modified 2 Months ago.

Error Delwaq2 by increasing the number of Processors

Youngling Posts: 13 Join Date: 6/25/16 Recent Posts

Hi,

I want to run delwaq2 on 28 processors. I used the nothreads command to manage the computations. When I use -nothreads 1 it runs fine, without errors. When I use -nothreads 2 or 3 it runs fine, with some warnings but the Simulation is not crashed. Using 4 and more processors the simulation will be crashed. I attached the simulation files from 1,2,3 and 4 processors. Could you tell me how can I solve this Problem?

Michelle Jeuken, modified 2 Months ago.

RE: Error Delwaq2 by increasing the number of Processors

Jedi Knight Posts: 156 Join Date: 1/21/13 Recent Posts

Hm, seems like you are running multiple instances of Delwaq at once. This is not how is parallelism in Delwaq works. Delwaq uses OpenMP parallelisation, so only one instance of Delwaq should be running on one node, which could use multiple threads. Seen from your screen dump you have an extra tool to launch multiple Delwaq's on 4 nodes. They will all try to write the same files, so this will crash...

It might be that the command line option -nothreads also trigers the multiple instances of Delwaq. It is best to set the number of threads in the input file of Delwaq itself in block 7 (which is terminated by #7) through the special constant nothreads. Like this:
 

 

CONSTANTS nothreads DATA 0.0


You can either set it to 0 (max number of threads) or to the number of threads you want. No command line argument is needed then.

If you need more info, look in the Input File Description manual (section 7.3.1.1).

 

Michelle

GS
Gholamreza Shiravani, modified 2 Months ago.

RE: Error Delwaq2 by increasing the number of Processors

Youngling Posts: 13 Join Date: 6/25/16 Recent Posts

Hi Michelle, thanks a lot. Now it works fine.