ffc team mailing list archive

["Garth N. Wells" <g.n.wells@xxxxxxxxxx>]

Johan Hoffman wrote:
> In connection with the dof-discussion; could we add geometry info to FFC?
> Like diameter, normals, tangents etc. From what I understand this info is
> already in FIAT, so it would amount to adding a mapping to FFC?

I think that this belongs more to the mesh. Diameter is already in 
DOLFIN, and normals should be added shortly (needed for DG which is 
currently being implemented).

Garth

> /Johan
>
>
>
>
> > Anders Logg wrote:
> > > On Mon, Dec 04, 2006 at 02:14:51PM +0100, Garth N. Wells wrote:
> > > > Could we add something to FFC to describe where the various degrees of
> > > > freedom live (on vertices, edges, internal)?
> > > >
> > > > Garth
> > > Yes we could, but I'd rather not. Why do we need it? I'd prefer if
> > > DOLFIN did not know anything about dofs, other than how to reorder
> > > them.
> > Not sure that it's this simple if you want to assemble some terms
> > block-wise. Also, for parallel assembly we might need to know where dofs
> > lie. I'm still thinking about this so I can't be concrete in what's
> > needed just yet.
> >
> > > I see two options:
> > >
> > >  1. Reorder the dofs computed by FFC, not knowing why and how they
> > >     are numbered.
> > This is one option I'm considering. Just take the FFC numbering, and run
> > a renumbering algorithm over it to minimise bandwidth.
> >
> > >  2. Compute a different mapping in FFC.
> > This could be difficult as it depends on properties of the mesh,
> > partition, etc. I think that this should remain simple.
> >
> > > I can be convinced otherwise of course, but I don't understand why
> > > this is needed.
> > >
> > > /Anders
> > > _______________________________________________
> > > FFC-dev mailing list
> > > FFC-dev@xxxxxxxxxx
> > > http://www.fenics.org/mailman/listinfo/ffc-dev
> >
> > _______________________________________________
> > FFC-dev mailing list
> > FFC-dev@xxxxxxxxxx
> > http://www.fenics.org/mailman/listinfo/ffc-dev