On Jun 9, 2011, at 5:50 PM, Jed Brown wrote: > On Fri, Jun 10, 2011 at 00:47, Barry Smith <bsmith at mcs.anl.gov> wrote: > So you are suggesting totally removing PCFieldSplitSetSchurPrecondition() and > instead having the user call MatSetApproximateSchurComplement() if they wish > to provide a matrix? > > Yeah, though I think it would still be useful to fall back to using the > diagonal block if nothing was provided by the user.
Absolutely, by default MatGetSchurComplement() should be providing the diagonal block if something else is not given by the user. This way the fieldsplit can just call MatGetSchurComplement() and needs to have no special code for "if user didn't provide anything". Right? Barry > The user can choose -pc_type none if they don't want to do anything with that > block.
