[petsc-users] Stop KSP if diverging

[Matthew Knepley]

On Wed, May 29, 2019 at 3:07 AM Edoardo alinovi via petsc-users <
petsc-users at mcs.anl.gov> wrote:

> Dear PETSc friends,
>
> Hope you are doing all well.
>
> I have a quick question for you that I am not able to solve by my self.
> Time to time, while testing new code features, it happens that KSP diverges
> but it does not stop automatically and the iterations continue even after
> getting a NaN.
>

I think you want


https://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/KSP/KSPSetErrorIfNotConverged.html

  Thanks,

    Matt


> In the KSP setup I use the following instruction to set the divergence
> stopping criteria (div = 10000):
>
> call KSPSetTolerances(myksp,  rel_tol,  abs_tol, div,  itmax,  ierr)
>
> But is does not help. Looking into the documentation I have found also:
>
> KSPConvergedDefault <https://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/KSP/KSPConvergedDefault.html#KSPConvergedDefault>(KSP <https://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/KSP/KSP.html#KSP> ksp,PetscInt <https://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/Sys/PetscInt.html#PetscInt> n,PetscReal <https://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/Sys/PetscReal.html#PetscReal> rnorm,KSPConvergedReason <https://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/KSP/KSPConvergedReason.html#KSPConvergedReason> *reason,void *ctx)
>
> Which I am not calling in the code. Is this maybe the reason of my
> problem? If yes how can I use KSPConvergedDefault
> <https://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/KSP/KSPConvergedDefault.html#KSPConvergedDefault> in
> FORTRAN?
>
> Thanks,
>
> Edo
>
> ------
>
> Edoardo Alinovi, Ph.D.
>
> DICCA, Scuola Politecnica,
> Universita' degli Studi di Genova,
> 1, via Montallegro,
> 16145 Genova, Italy
>
> Email: edoardo.alinovi at dicca.unige.it
> Tel: +39 010 353 2540
> Website: https://www.edoardoalinovi.com/
>
>
>

-- 
What most experimenters take for granted before they begin their
experiments is infinitely more interesting than any results to which their
experiments lead.
-- Norbert Wiener

https://www.cse.buffalo.edu/~knepley/ <http://www.cse.buffalo.edu/~knepley/>
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