[petsc-users] Question about applying algebraic multigrid (AMG) PC and multilevel Schwarz PC

[Mark Adams]

On Fri, Feb 10, 2023 at 9:17 AM ­권승리 <ksl7912 at snu.ac.kr> wrote:

> Dear petsc developers.
>
> Hello.
> While I was applying the preconditioner in contact with the FEM code, I
> had some questions.
>
> How can I apply the AMG PC and the multilevel Schwarz PC in the FEM code?
> Purpose is to compare which PC is better in the FEM code with contact
> situation.
>
> In my case, the Jacobi PC could be easily applied as shown in the example
> below. However, AMG and multilevel have too many options.
>
> ex) ./app -ksp_type gmres -pc_type jacobi -ksp_view
>

You can use the built-in AMG PC with: -pc_type gamg

Technically AMG is a  multilevel Schwarz PC, but I think you may be
referring to: -pc_type bddc

All solvers are equipped with default parameters that tend to be
optimized for robustness rather than peak performance and they are a good
place to start.

Thanks,
Mark


> Best regards
>
> Seung Lee Kwon
> --
> Seung Lee Kwon, Ph.D.Candidate
> Aerospace Structures and Materials Laboratory
> Department of Mechanical and Aerospace Engineering
> Seoul National University
> Building 300 Rm 503, Gwanak-ro 1, Gwanak-gu, Seoul, South Korea, 08826
> E-mail : ksl7912 at snu.ac.kr
> Office : +82-2-880-7389
> C. P : +82-10-4695-1062
>
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