How to speed up CFDEM

Submitted by rqwang on Tue, 08/23/2011 - 14:26

Hi,

I wonder how to speed up CFDEM.

I am running a particle-laden jets. To reach the steady state, I have to run for a long time.

Could anyone tell me where I can modify to speed up, especially in DEM/in.xxxx

Thanks.

rq

Forums:

ckloss's picture

ckloss | Fri, 08/26/2011 - 14:54

there are multiple ways to speed up your DEM simulation. First of all, you should look at the timing statistics what comsumes the most of the time. If e.g. the neigh time is more that say 10% you can tune the skin distance and binsize, if the other time is very high, you may suffer from load imbalance - but it all depends on your problem and also the machine you are running on. If you have further questions, feel free to ask (please use the DEM forum).

Christoph

venes520 | Wed, 03/28/2012 - 11:30

Hi Christoph,
Can you give more specific instructions on how to speed up the simulation?
You mention the timing statistics, how do I access this timing statistics?
And how doesn't the skin distance and timestep affect the simulation speed (not the total simulation time).
By the way, is there a way to determine the optimal tiemstep and skin distance?

Thanks in advance.

Cheers
Anson Liang

dnojiri | Thu, 05/31/2012 - 13:58

Hellou

Does "load imbalance" means that the number of atoms alocated to each processor differ greatly?
if the answer is yes. How can I make the load balanced? Does liggghts have commands to achieve this?

Im currently pouring atoms in a cylinder, and then stirring them with a stl paddle.
The simulation runs faster with one processor than with four processors. Which is contrary to what I was expecting.

Any pointer that you could give me?

cgoniva's picture

cgoniva | Wed, 06/06/2012 - 15:27

Hello,

there is a load balancing method, but not in the public release.
Concerning the moving mesh performance, there will be a better parallel perfromance of moving meshes in future versions.

Cheers,
Chris