[petsc-users] Issue with KSPSolve when the number of CPUs are larger than four

Wed Jan 10 15:41:15 CST 2018

Hi,

I hope you are doing well. I am Mohammad, a PhD student of environmental
sciences at the University of Arizona.

I do appreciate any help that can shed some light on the issue I have:
recently I have added a feature to an existing parallel code called
'parswms' which solves water and solute transport in soils. The code uses
MPI and parmetis for the parallelization purposes and petsc package
(KSPSolve) for solving linear systems. I have it installed on the UofA HPC
: the issue is that it works well if the number of CPUs are up to 4! but
when I add to this number the numerical linear solver (here it is 'KSPCGS')
stops with the error of 'KSP_DIVERGED_NANORINF'.

Would you mind please giving me some hints, suggestions or resources in
this regard?

Best Regards,
Mohammad
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