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 <[email protected]> wrote: > Matthew Knepley <[email protected]> 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)] >
