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 <aduar...@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
