EDEM Command Line Input on Mesh Size

Yu Wang_21521

I have submitted two batch jobs in the server, one of the batch jobs contains the command of mesh size via adding "-g 1.5" (defining the mesh size as 1.5 R) in the command line, and the other does not contain mesh size command (assuming the default mesh size as 2.5 R), and all other command lines are the same. However, after getting the result, I found that the simulation times taken for two batch jobs were the same, which went against my assumptions, as I supposed the smaller mesh size would take more time. Are there any command lines incorrect or did I miss anything to input?

Stephen Cole

Hi Yu,

 

If you don't specify a grid size value then EDEM will run with what is set in the EDEM Simulator tab in the user interface.  It won't always default to 2.5 unless this is what is set in the Simulator.

I would expect 1.5 Rmin to be slower as you typically see a big drop off in speed below 2.5 Rmin but this is very case and particle size dependent.  You can add in the command --debug-logger "c:\myfolder\myfile.txt" and this will write out a text file to the specified location with some timing details.  You would be able to see how long contact detection takes in the debug log which may show some differences.

 

Also worth mentioning if you run with CUDA GPU this doesn't use the grid, it automatically sets the contact detection method, the rmin value only applies for CPU or OpenCL GPU runs.

Regards

Stephen

 

Yu Wang_21521

Stephen Cole_21117 said:

Hi Yu,

 

If you don't specify a grid size value then EDEM will run with what is set in the EDEM Simulator tab in the user interface.  It won't always default to 2.5 unless this is what is set in the Simulator.

I would expect 1.5 Rmin to be slower as you typically see a big drop off in speed below 2.5 Rmin but this is very case and particle size dependent.  You can add in the command --debug-logger "c:\myfolder\myfile.txt" and this will write out a text file to the specified location with some timing details.  You would be able to see how long contact detection takes in the debug log which may show some differences.

 

Also worth mentioning if you run with CUDA GPU this doesn't use the grid, it automatically sets the contact detection method, the rmin value only applies for CPU or OpenCL GPU runs.

Regards

Stephen

 

Dear Stephen,

 

Thank you for your great help!!! I can check the mesh size by adding write out a text file.

Currently, I am working on the adjustment of the time step size, is there any alternative way to adjust the Rayleigh time step size in the command line? I am aware that I can input "-t 1.0e-06" to set the actual value of time step size, but if I would like to apply 30% Rayleigh time step size, is there any command line to help me achieve this?

 

Best Regards,

Yu

Stephen Cole

Yu Wang_21521 said:

Dear Stephen,

 

Thank you for your great help!!! I can check the mesh size by adding write out a text file.

Currently, I am working on the adjustment of the time step size, is there any alternative way to adjust the Rayleigh time step size in the command line? I am aware that I can input "-t 1.0e-06" to set the actual value of time step size, but if I would like to apply 30% Rayleigh time step size, is there any command line to help me achieve this?

 

Best Regards,

Yu

Hi Yu, 

No options for setting % time-step via command line unfortunatly. If you don't put a value to the command line it uses what is set as default in the Simulator GUI.  So if the simulation is set at 30% it would default to that but you can't change it via the command prompt.

Regards

Stephen