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npr_yz setting via cesm script in CESM1.2.0

R

rambhari0123@gmail_com

Member
Dear CESM Users ,We have ported cesm1.2.0 on IITD HPC (A newly set up High performance computing ). I wanted to some time or benchmarking test for this machine using a increasing number of processor/core for F_2_2000_CAM5 compset with f09_f09 horizontal resolution. I have taken a total of 2304 cores (96 nodes with 24 Maximum Pes /node) .I faced an facen an error while doing cesm setup.The details steps i used to create the case as given below.1.) /home/apps/cesm/cesm1_2_0/scripts/create_newcase -case Test_B_5_2304 -res f09_f09 -compset F_2000_CAM5 -mach IITD -mpilib mpich -compiler pgion doing ./cesm setup---- Creating batch script Test_B_5_2304.run
Locking file env_mach_pes.xml
Running preview_namelist script
 infile is /home/cas/phd/asz118159/CESM_Benchmarking_Runs/Test_B_5_2304/Buildconf/cplconf/cesm_namelist
CAM build-namelist - ERROR: fv_decomp_set failed to find a decomposition.
  npr_yz needs to be set by the user. at /home/apps/cesm/cesm1_2_0/models/atm/cam/bld/build-namelist line 3479.
ERROR: cam.buildnml.csh failed
ERROR: /home/cas/phd/asz118159/CESM_Benchmarking_Runs/Test_B_5_2304/preview_namelists failed: 25344
----------------------Before this i ran it sucessfully with 1728 ( 72 nodes X 24 pes) . I guess there is a limit on maximum number of ntask i can select based on resolutions and compset ??can i change it using some npr_yz setting ?? if yes then how will i do it, as i doesn't found anything regarding it .xml created in case.Please help.Thanking you in anticipation.Ram SinghCAS,IIT Delhi, New Delhi 110016. 
 
J

jedwards

CSEG and Liaisons
Staff member
f09 cannot scale beyond 1728 mpi tasks in cesm1.2.x  the only way to increase processors beyond this is by adding threads
 
E

eaton

CSEG and Liaisons
For FV on 0.9x1.25 grid the max number of tasks is 1920.  The corresponding namelist setting is npr_yz=64,30,30,64That setting is determined from the maximum number of latitude subdomains being 64 (number of lat grid pts divided by 3) and the maximum number of vertical subdomains being 30 (the number of model levels). 
 
R

rambhari0123@gmail_com

Member
Thanks you Eaton and jedwards.
It confirms my conclusion after reading about the settings.
I request admin to help me on hybrid parallelism(adding Threads) for more cores.Thanks
 
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