[petsc-users] PETSc geometric multigrid use

[Barry Smith]

  I don't think you want to use -pc_type gamg if you want to use geometric multigrid. You can can use -pc_type mg and the DMDA. The only thing I think you need to change from the default use of DMDA and -pc_type mg is to provide custom code that computes the interpolation between levels to take into account the curvilinear grids.

  Barry


> On Dec 1, 2022, at 3:43 PM, Alfredo J Duarte Gomez <aduarteg at utexas.edu> wrote:
> 
> Good morning,
> 
> Good afternoon,
> 
> I am testing the performance of some preconditioners on a problem I have and I wanted to try geometric multigrid. I am using a DMDA object and respective matrices (the mesh is structured, but not rectangular, it is curvilinear)
> 
> I have used the default version of algebraic multigrid (that is -pc_gamg_type agg) very easily.
> 
> When I try to use  -pc_gamg_type geo, it returns an error.
> 
> What additional lines of code do I have to add to use the geo option? 
> 
> Or does this require some sort of fast remeshing routine, given that I am using curvilinear grids?
> 
> Thank you and have a good day.
> 
> -Alfredo
> 
> -- 
> Alfredo Duarte
> Graduate Research Assistant
> The University of Texas at Austin

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20221201/9efca104/attachment.html>