Do you want to refine the geometry or are you fine with the current one? What kind of hardware are you planning on using (GPU, single-node…)? Do you have a configuration for which LSC fails or does not give you good-enough performance?
Thanks, Pierre > On 9 May 2025, at 9:08 PM, Mark Adams <mfad...@lbl.gov> wrote: > > Hi Hardik, > > The domain shape is not critical but the element shapes are. Your 100:1 > domain aspect ratio is bad if you have N^3 mesh and thus element aspect > ratios of 100:1. > If that is the case then you probably want to look at semi-coarsening > multigrid. > > Mark > > On Fri, May 9, 2025 at 9:55 AM Hardik Kothari <hardik.koth...@corintis.com > <mailto:hardik.koth...@corintis.com>> wrote: >> Dear PETSc team, >> >> We are solving the Stokes equations using PETSc (via Firedrake) on a highly >> anisotropic 3D domain (L_x=1, L_y=0.01, L_z=0.1). >> >> In this setup, standard Schur complement preconditioners using a mass >> inverse for pressure struggle to converge. We could solve the problem with >> the LSC preconditioner (solver parameters are shown in the script). >> >> We have the following questions: >> Why standard preconditioners struggle in such domains? >> Why is the preconditioned residual norm for the Schur complement system much >> higher than the true residual norm? >> Would you recommend alternative or more robust preconditioners for such >> geometries? >> >> Thank you for your help. >> >> Best regards, >> Hardik >> >> >> >> >> HARDIK KOTHARI >> >> hardik.koth...@corintis.com <mailto:hardik.koth...@corintis.com> >> >> Corintis SA >> EPFL Innovation Park Building C >> 1015 Lausanne >> >> >> >> >> Here at Corintis we care for your privacy. That is why we have taken >> appropriate measures to ensure that the data you have provided to us is >> always secure
