dolfin team mailing list archive

[Anders Logg <logg@xxxxxxxxx>]

On Tue, Oct 17, 2006 at 03:09:50PM +0200, Garth N. Wells wrote:

> > and you have it. For any cell in that mesh, you may then do
> > 
> >     uint* edges = cell.connections(1);
> > 
> > Which gives you the global edge numbers for the three edges of the
> > cell. The local numbers are 0, 1, 2.
> > 
> > Is that what you mean?
> > 
> 
> What I would like is the other way around. For a given facet, I need to
> it's local ID (0, 1 or 2) relative to the cells which is it connected
> to. Basically, on the boundary, I now have the facet and the mesh cell,
> but I don't know the local facet number (FFC generate output for each case).
> 
> I could use the above way and iterate over each mesh cell which has a
> boundary facet, and work out which facet is on the boundary.

ok, now I remember. I forgot we had this before by localID().

Is this needed only for the boundary? If so, we could add it as
another MeshFunction that gets computed when the boundary is
generated. In that case, we compute this in BoundaryComputation.

Or do we need something more general, so for any given pair of
entities (e0, e1), e0 can ask e1: Who am I to you?

/Anders