[petsc-users] Bug report VecNorm

[Matthew Knepley]

We already merged the fix.

  Thanks,

    Matt

On Mon, Dec 11, 2023 at 6:00 AM Barry Smith <bsmith at petsc.dev> wrote:

>
>    I don't fully understand your code and what it is trying to
> demonstrate, but VecGetArrayWrite is Logically Collective. Having
>
>   if(rank == 0)
>   {
>     PetscCall(VecGetArrayWrite(vec, &xx));
>     PetscCall(VecRestoreArrayWrite(vec, &xx));
>   }
>
> is not allowed.  The reason is that VecRestoreArrayWrite() changes the
> PetscObjectState of the vector, and this state must be changed consistently
> across all MPI processes that share the vector.
>
>
>
> On Dec 10, 2023, at 2:40 AM, Stephan Köhler <
> stephan.koehler at math.tu-freiberg.de> wrote:
>
> Dear PETSc/Tao team,
>
> there is a bug in the voector interface:  In the function
> VecNorm, see, eg.
> https://petsc.org/release/src/vec/vec/interface/rvector.c.html#VecNorm
> line 197 the check for consistency in line 214 is done on the wrong
> communicator.  The  communicator should be PETSC_COMM_SELF.
> Otherwise the program may hang when PetscCheck is executed.
>
> Please find a minimal example attached.
>
>
> Kind regards,
> Stephan Köhler
>
> --
> Stephan Köhler
> TU Bergakademie Freiberg
> Institut für numerische Mathematik und Optimierung
>
> Akademiestraße 6
> 09599 Freiberg
> Gebäudeteil Mittelbau, Zimmer 2.07
>
> Telefon: +49 (0)3731 39-3188 (Büro)
>
> <minimal_ex_vec_norm.cpp><OpenPGP_0xC9BF2C20DFE9F713.asc>
>
>
>

-- 
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/>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20231211/0b3b8b2d/attachment.html>