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

[Mohammad Gohardoust]

Thanks Barry,

some 'nan's in the rhs matrix caused the issue strangely when cpu numbers
gets larger than 4.

Best,
Mohammad

On Wed, Jan 10, 2018 at 5:30 PM, Smith, Barry F. <bsmith at mcs.anl.gov> wrote:

>
>   You can also run with -fp_trap to find where the nan/inf first appears
> as well as run with -ksp_monitor to see what is happening before the tragedy
>
>   Barry
>
>
> > On Jan 10, 2018, at 3:41 PM, Mohammad R. Gohardoust <
> gohardoust at email.arizona.edu> wrote:
> >
> > 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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