There are several but I am updating *src/snes/tests/ex13.c * <https://gitlab.com/petsc/petsc/-/merge_requests/6875/diffs#diff-content-5a7dc636e85ce214f0a7dcf710f45f1e6800c0d4> now, in branch adams/gamg-fast-filter <https://gitlab.com/petsc/petsc/-/tree/adams/gamg-fast-filter>. but main is fine (it should get merged very soon). It does what you want scales forever, but it does not have Neumann BCs. I might be able to add that, but not today.
Mark On Mon, Sep 18, 2023 at 11:16 AM Khurana, Parv <[email protected]> wrote: > Hello PETSc users, > > > > Thank you for this very active community of users and the mailing list. > > > > I am looking for a PETSc example which solves the Poisson equation on a 2D > domain using FEM (or HO-FEM if possible). I would like the following: > > 1. The example should be formulated fully on PETSc, and to be solved > with KSP objects in PETSc. > 2. The problem should scale up to a few hundred processors (ideally > 1000 procs). > 3. Ideally on a unit square with either Square or Triangle element > discretization. > 4. There should be an option to specify Dirichlet/Neumann-type BCs on > the boundaries. > > > > I was wondering if someone could point me to such an example as I am > relatively new to PETSc – and I am trying to avoid reinventing the wheel. I > have had a look at Examples 29,32,50 and 66 in the PETSc tutorials – while > they are very close to what I need I am not sure if they scale to a few > hundred processors. Furthermore, I am aware that I can formulate such a > problem with FENICS/Firedrake with relative ease and these software > interfaces with PETSc quite well. However, I am just trying to see if such > an application already exists purely in PETSc. > > > > Thanks, and Best > > Parv > > >
