[petsc-users] Bug report LMVM matrix class

[Barry Smith]

  Thanks for the bug report with reproducing example. I have a fix in https://gitlab.com/petsc/petsc/-/merge_requests/5797

  Barry


> On Nov 2, 2022, at 6:52 AM, Stephan Köhler <stephan.koehler at math.tu-freiberg.de> wrote:
> 
> Dear PETSc/Tao team,
> 
> it seems to be that there is a bug in the LMVM matrix class:
> 
> In the function MatCreateVecs_LMVM, see, e.g., https://petsc.org/release/src/ksp/ksp/utils/lmvm/lmvmimpl.c.html at line 214.
> it is not checked if the vectors  *L, or *R are NULL.  This is, in particular, a problem if this matrix class is combined with the Schur complement matrix class, since MatMult_SchurComplement
> calls this function with NULL as *R, see, e.g. https://petsc.org/release/src/ksp/ksp/utils/schurm/schurm.c.html at line 66.
> 
> I attach a minimal example.  You need to modify the paths to the PETSc installation in the makefile.
> 
> Best 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 39-3173 (Büro)
> 
> <Minimal_example_schur_lmvm.tar.gz><OpenPGP_0xC9BF2C20DFE9F713.asc>

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