Algebraic multigrid can be used directly, -pc_type gamg -pc_gamg_agg_nsmooths 1. Geometric either required that you use the PCMG interface to set interpolation (and provide a coarse operator for non-Galerkin) or use a DM that provides coarsening capability.
What kind of problem are you solving? On Oct 28, 2012 6:09 AM, "w_ang_temp" <w_ang_temp at 163.com> wrote: > Hello, > I want to use the multigrid as a preconditioner. The introduction about > it in the manual is little. > So are there some typical examples or details about multigrid? Is it used > just like other preconditioners > like jacobi, sor, which can be simply used in the cammand line options? > Thanks. > Jim > > > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20121028/b0c2a1ff/attachment.html>
