On Thu, 7 Jan 2010 14:52:41 -0600, Barry Smith <bsmith at mcs.anl.gov> wrote:
> There would be no SNES in this context! One would be able to > cleanly and simply (more so then today) put geometric multigrid inside > a Schure fieldsplit preconditioner. If one can't then we screwed up > our new design. I think we're agreeing. My comment was just a retort to the claim that linear problems are silly. They are silly if that's your end goal, and I believe they are still silly when using a scheme where the quality of your solution depends on the quality of the linear solve (as in a semi-implicit scheme), but having a nice interface for linear MG is important when it goes inside a preconditioner. In contrast, I think that all special treatment of linear problems could be stripped out of TS with no ill consequences. Jed
