On Thu, Aug 5, 2010 at 2:10 AM, Jed Brown <jed at 59a2.org> wrote: > On Thu, 5 Aug 2010 00:21:13 -0500, Matthew Knepley <knepley at gmail.com> > wrote: > > If someone tells us, "I have a Stokes problem", we could search for 0 > > diagonals and create the partition for FS. > > I suppose this would work for some common cases, but there are lot of > discretizations and pressure-dependent constitutive relations/boundary > conditions that have nonzeros in the pressure block. I think some slip > conditions can also produce zero or negative values in the momentum > block. >
Do not disagree. > I'm not convinced that it's so much to ask people to provide an index > set, considering that FieldSplit is a somewhat advanced thing anyway > (based on sheer number of choices available, and (typical) sensitivity > to those choices). I guess the point here is somewhat like the point of DAs. It is a very limited thing, but something many people do. So we provide a way to most easily do the very limited thing. Not sure if this is useful enough, but it might be. Matt > > Jed > -- What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead. -- Norbert Wiener -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.mcs.anl.gov/pipermail/petsc-dev/attachments/20100805/c7b926d7/attachment.html>