multi-instances run of CESM

[huihuojia@163_com]

I want to do multi-instances run of CESM, and the instance number I intend to use is 80, and the compset I use is:
2000_CAM5_CLM40%SP_CICE%PRES_DOCN%DOM_RTM_SGLC_SWAV
in which, CAM/CLM/CICE are active components.
./xmlchange NINST_ATM=80
./xmlchange NINST_LND=80
./xmlchange NINST_ICE=80
./xmlchange NINST_ROF=1
./xmlchange NINST_OCN=1
And I will turn off the ROF: ./xmlchange RTM_MODE='NULL'.


and because the computational nodes are limited in cluster machine, so I want to use batches to submit the jobs, suppose I have 80 instances, then I want to have 20 instances per batch, and submit in 4 batches.

Will the result of 4 batches be different from the 80 instances run in 1 batch?

Thanks

 

[gaoyanqiujuly11th@163_com]

I want to know the answer of this question. If you get the answer, please send it to my email gaoyanqiujuly11th@163.comThank you very much!

 

[jedwards]

I think that by default you will get 80 equivalent results and the 4 runs of 20 should give the same answer as 1 run of 80.   But I assume that you want to apply some kind of purturbation so that each instance gets a different result.  To do that you would normally add a perturbation to the atm temperature field using the variable pertlim in each of the members user_nl_cam  namelist - careful application of the pertlim value should allow you to reproduce the same result with 4 runs of 20 members as with a run of 80 members.    But performance wise you could do this with 80 single instance runs more efficiently.