Real.exe got "check comm_start, nest_pes_x, nest_pes_y" when set nproc_x nproc_y other than -1

[xiao.zh]

Hi all, I got this problem while running real.exe.
Running real.exe was good with nproc_x and nproc_y =-1,when I tried to set nproc_x and nproc_y =4, I got this error:

taskid: 0 hostname: cn060757
-------------- FATAL CALLED ---------------
FATAL CALLED FROM FILE: <stdin> LINE: 5895
check comm_start, nest_pes_x, nest_pes_y settings in namelist for comm 1

Does anyone know why this could happen?

 

[Ming Chen]

It is recommended to turn off nproc_x and nproc_y because WRF will automatically decompose the domain.
If you want to manually decompose, then nproc_x * nproc_y must be equal to the total number of processors you use to run the case.

By default, the decomposition of MPI tasks is computed as the two closest multiplicative factors. For example: 32 MPI tasks = 4x8 decomposition, NOT 2x16. By specifying nproc_x and nproc_y, you can determine how to conduct the decomposition.

 

[xiao.zh]

It is recommended to turn off nproc_x and nproc_y because WRF will automatically decompose the domain.
If you want to manually decompose, then nproc_x * nproc_y must be equal to the total number of processors you use to run the case.

By default, the decomposition of MPI tasks is computed as the two closest multiplicative factors. For example: 32 MPI tasks = 4x8 decomposition, NOT 2x16. By specifying nproc_x and nproc_y, you can determine how to conduct the decomposition.

Hi Ming,
Thanks for your timely reply.
I used the default and tried the number_of_procs.py, it worked fine for my case now.

Xiao