Hi Folks, Maybe I'm doing something wrong because I'm not that familiar with the current workings of multigrid in PETSc, but I was playing with Jed's SNES ex48 tutorial example (hydrostatic ice sheet flow), and was puzzled to find that trying to run a very simple variation:
./ex48 -da_refine 1 -pc_type mg results in a failure. The problem appears to be that PETSc defaults to an SOR smoother, but symmetric SOR isn't implemented for the SBAIJ matrices (with block size > 1) that ex48 uses: [0]PETSC ERROR: No support for this operation for this object type [0]PETSC ERROR: SSOR for block size > 1 is not yet implemented Is this the desired behavior, or should PETSc default to a smoother like Jacobi that is implemented for this matrix type? --Richard P.S. Jed, if I just want to take the default problem and scale it up in size (for some simple parallel performance tests), is using -da_refine <some number> and a Jacobi smoother for the various levels reasonable? Or do I need to do something more sophisticated? (Sorry if this requires another thread.)
