[petsc-users] Using factored complex matrices from MUMPS as a preconditioner in PETSC

[Evan Um]

Hi Barry,

Thanks for your comments. To activate block low rank (BLR) approximation in
MUMPS version 5.1.1, a user needs to turn on the functionality (i.e.
ICNTL(35)=1) and specify the tolerance value (e.g. CNTL(7)=1e-4). In PETSC,
I think that we can set up ICNTL and CNTL parameters for MUMPS. I was
wondering if we can still use BLR approximation for a preconditioner for
Krylov solvers.

Best,
Evan


On Sat, Sep 23, 2017 at 6:45 PM, Barry Smith <bsmith at mcs.anl.gov> wrote:

>
> > On Sep 23, 2017, at 8:38 PM, Evan Um <evanum at gmail.com> wrote:
> >
> > Dear PETSC Users,
> >
> > My system matrix comes from finite element modeling and is complex and
> unstructured. Its typical size is a few millions-by a few millions. I
> wondering if I can use MUMPS parallel direct solver as a preconditioner in
> PETSC. For example, I want to pass factored matrices to Krylov iterative
> solvers such as QMR. Is there any PETSC+MUMPS example code for the purpose?
>
>   You don't pass factored matrices you just pass the original matrix and
> use -pc_type lu -pc_factor_mat_solver_package mumps
>
> > Can PETSC call the latest MUMPS that supports block low rank
> approximation?
>
>   No, send us info on it and we'll see if we can add an interface
>
>
> >
> > In advance, thank you very much for your comments.
> >
> > Best,
> > Evan
> >
> >
> >
> >
> >
>
>
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