[petsc-users] error when solving a linear system with gmres + pilut/euclid

[Matthew Knepley]

On Mon, Aug 24, 2020 at 6:27 PM Barry Smith <bsmith at petsc.dev> wrote:

>
>    Alfredo,
>
>       This should never happen. The input to the VecMAXPY in gmres is
> computed via VMDot which produces the same result on all processes.
>
>        If you run with -pc_type bjacobi does it also happen?
>
>        Is this your custom code or does it happen in PETSc examples also?
> Like src/snes/tutorials/ex19 -da_refine 5
>
>       Could be memory corruption, can you run under valgrind?
>

Couldn't it happen if something generates a NaN? That also should not
happen, but I was allowing that pilut might do it.

  Thanks,

    Matt


>     Barry
>
>
> > On Aug 24, 2020, at 4:05 PM, Alfredo Jaramillo <
> ajaramillopalma at gmail.com> wrote:
> >
> > Dear PETSc developers,
> >
> > I'm trying to solve a linear problem with GMRES preconditioned with
> pilut from HYPRE. For this I'm using the options:
> >
> > -ksp_type gmres -pc_type hypre -pc_hypre_type pilut -ksp_monitor
> >
> > If I use a single core, GMRES (+ pilut or euclid) converges. However,
> when using multiple cores the next error appears after some number of
> iterations:
> >
> > [0]PETSC ERROR: Scalar value must be same on all processes, argument # 3
> >
> > relative to the function VecMAXPY. I attached a screenshot with more
> detailed output. The same happens when using euclid. Can you please give me
> some insight on this?
> >
> > best regards
> > Alfredo
> > <Screenshot from 2020-08-24 17-57-52.png>
>
>

-- 
What most experimenters take for granted before they begin their
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https://www.cse.buffalo.edu/~knepley/ <http://www.cse.buffalo.edu/~knepley/>
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