[petsc-users] Recursive field split with MatNest

[Colin McAuliffe]

Thanks for the comments Jed and Matt, I'll defer to your judgement
regarding the implementation that is the least intrusive. I'll take a look
at this later on when I have time.
Colin

On Mon, Jan 12, 2015 at 12:29 PM, Jed Brown <jed at jedbrown.org> wrote:

> Matthew Knepley <knepley at gmail.com> writes:
> > I don't like this business of ISes holding pointers to other ISes. This
> > fundamentally
> > changes the model. The hashing sounds workable.
>
> ISs are immutable and a reference would probably be held anyway, so I
> don't think it's evil.
>
> We also have to think about recursive composition and I'd rather not
> have to walk a subset DAG.  If we hash, the IS would just store a list
> of "known subset hashes" with the semantic
>
>   (A ∪ B).known_subset_hashes =
>       A.known_subset_hashes ∪ B.known_subset_hashes ∪ [hash(A)] ∪ [hash(B)]
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20150112/8e8db930/attachment.html>