On Fri, Feb 24, 2012 at 2:39 PM, Barry Smith <bsmith at mcs.anl.gov> wrote:
> > On Feb 24, 2012, at 2:23 PM, Jed Brown wrote: > > > We need a richer field interface. Some way for a client of DM to > discover vector and tensor structure. > > No idea what a tensor is, but DMGetSubDMS(dm,PetscInt *cnt,IS *ises,DM > *dms); and DMPushSubDMType(DM,"name of a type of splitting like u,v,p or > velocity,p"); DMPopSubDMType(); and DMGetAvailableSubDMTypes(DM,char **); > > Do you need more than that? > Yuck Yuck Yuck. Why are we persisting in shoving all of the index stuff into the DM interface. I think this is so unwieldy and complicated. PetscSection is small, powerful, and does everything suggested and more. I see no argument in support of stuff like the above. Matt > Barry > > Note that current DMDA's default subdms served up would be a DM for each > field consisting of one of the degrees of freedom per node and it could > also serve up DMs that represent any collections of those for example dof > 0 and 1 per node, then dof 2 per node. We'll need to come up with some > naming convention for these. > > > > Possibly also (eventually) a way to solve equations of state so that we > can formulate reduced problems in non-conservative variables. > > > > On Feb 24, 2012 2:19 PM, "Matthew Knepley" <knepley at gmail.com> wrote: > > On Fri, Feb 24, 2012 at 1:58 PM, Jed Brown <jedbrown at mcs.anl.gov> wrote: > > http://petsc.cs.iit.edu/petsc/petsc-dev/rev/518ff70e8a0a > > > > Matt, I want to get rid of these conditionals, not add more. We should > have a DM base interface for getting fields on which to split, that common > interface should _replace_ the DMComposite specialization. > > > > I agree. However, I won't put anything in until I do it by hand once. > > > > Also, I was tempted to just promote DMGetGlobalISes(), but its not quite > right. I am planning > > to put the IS method in PetscSection. I am hoping eventually DMDA uses > PetscSection for > > layout. > > > > Matt > > > > -- > > 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 > > -- 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/20120224/4dfcf8e1/attachment.html>
