On Sun, May 8, 2022 at 12:44 AM markwinpe <[email protected]> wrote: > Dear PETSc’s developers, > > In the context of unstructured applications developed by PETSc’s > DMPlex, if the ASM is used for preconditioning, is it algebraic (based on > matrix graph) or geometric (based on Metis partition)? >
Algebraic. DMPlex is a topology thing and I don't know if it helps ASM. ASM will have one subdomain per process by default, it does not try to create subdomains for you. You can give AMS domains that you can create with a partitioning (Metis the common one to use). see https://petsc.org/main/docs/manualpages/MatOrderings/MatPartitioningCreate and https://petsc.org/main/docs/manualpages/PC/PCASMSetTotalSubdomains/ Mark When the ASM preconditioner is associated with a specific DM object, I > found there is only the implementation of DMCreateDomainDecomposition > <https://www.petsc.org/release/src/dm/impls/da/dadd.c.html#DMCreateDomainDecomposition_DA> > for > DA in PCSetUp_ASM, and there is no implementation for DMPlex. So I guess > the ASM is algebraic for DMPlex, is that right ? > > > > Best, > > > Wenpeng >
