On Feb 12, 2013, at 11:24 PM, Jed Brown <jedbrown at mcs.anl.gov> wrote:
> > On Tue, Feb 12, 2013 at 11:17 PM, Matthew Knepley <knepley at gmail.com> > wrote: > Yes. PetscSection represents groups of numbers, and you can see the grouping. > > IS is a map from (int) -> (int), but PetscSection is a map from (int) -> > (int,int) where the pair is interpreted to mean an interval of non-negative > extent. If it's any use, an IS could be thought of as the special case (int) > -> (int,1). Is it? Maybe a more general definition of PetscSection would be better as map from (int) -> IS Matt's current usage is very restricted to only contiguous blocks of elements in a group. Need that be it? Should that be it? Barry > > > What queries "do not just return members of this list" in PETSc section? > (That is queries we wish to retain anyways). > > For example, you can ask "how many items are in group p?". This is crucial, > and the whole point of the structure. > I don't see how you can recover that information from just the list of dof > numbers. > >
