> On Jan 10, 2023, at 2:19 PM, Mark Lohry <[email protected]> wrote: > >> Is DILU a point-block method? We have -pc_type pbjacobi (and vpbjacobi if >> the node size is not uniform). The are good choices for scale-resolving CFD >> on GPUs. > > I was hoping you'd know :) pbjacobi is underperforming ilu by a pretty wide > margin on some of the systems i'm looking at. > >> We don't have colored smoothers currently in PETSc. > > So what happens under the hood when I run -mg_levels_pc_type sor on GPU? Are > you actually decomposing the matrix into lower and computing updates with > matrix multiplications? Or is it just the standard serial algorithm with > thread safety ignored?
It is running the regular SOR on the CPU and needs to copy up the vector and copy down the result. > > On Tue, Jan 10, 2023 at 1:52 PM Barry Smith <[email protected] > <mailto:[email protected]>> wrote: >> >> We don't have colored smoothers currently in PETSc. >> >> > On Jan 10, 2023, at 12:56 PM, Jed Brown <[email protected] >> > <mailto:[email protected]>> wrote: >> > >> > Is DILU a point-block method? We have -pc_type pbjacobi (and vpbjacobi if >> > the node size is not uniform). The are good choices for scale-resolving >> > CFD on GPUs. >> > >> > Mark Lohry <[email protected] <mailto:[email protected]>> writes: >> > >> >> I'm running GAMG with CUDA, and I'm wondering how the nominally serial >> >> smoother algorithms are implemented on GPU? Specifically SOR/GS and ILU(0) >> >> -- in e.g. AMGx these are applied by first creating a coloring, and the >> >> smoother passes are done color by color. Is this how it's done in petsc >> >> AMG? >> >> >> >> Tangential, AMGx and OpenFOAM offer something called "DILU", diagonal ILU. >> >> Is there an equivalent in petsc? >> >> >> >> Thanks, >> >> Mark >>
