dolfin team mailing list archive

[Johan Hake <johan.hake@xxxxxxxxx>]

On Wednesday December 1 2010 14:52:32 Garth N. Wells wrote:
> On 01/12/10 22:25, Johan Hake wrote:
> > On Wednesday December 1 2010 14:06:59 Anders Logg wrote:
> >> On Wed, Dec 01, 2010 at 01:51:01PM -0800, Johan Hake wrote:
> >>> On Wednesday December 1 2010 11:19:28 noreply@xxxxxxxxxxxxx wrote:
> >>>> ------------------------------------------------------------
> >>>> revno: 5346
> >>>> committer: Garth N. Wells<gnw20@xxxxxxxxx>
> >>>> branch nick: dolfin-all
> >>>> timestamp: Wed 2010-12-01 19:15:42 +0000
> >>>> 
> >>>> message:
> >>>>    Re-working of Function interfaces for removal of Data object.
> >>>>    
> >>>>    Nearly all test running, but logic needs to be checked. Problem
> >>>>    remains
> >>>> 
> >>>> with demos that use facet info.
> >>>> 
> >>>>    Also need to sort out determning whether or nor a ufc::cell belongs
> >>>>    to a
> >>>> 
> >>>> given mesh. modified:
> >>> There is a whole bunch of functionality that is lost with not having
> >>> access to a dolfin::Cell. Should this be added to ufc::cell?
> >> 
> >> I assume we will keep all existing functionality in place, in
> >> particular the functions defined in SpecialFunctions.h.
> > 
> > My point is that in the data argument you could access a dolfin::Cell.
> > This you cannot do now. I think this is a no go if we cannot find a
> > substitute for the lost functionality.
> 
> We haven't lost much, since nearly everything that was in
> SpecialFunctions.h is now in UFL/FFC. What remains (e.g. FacetArea)
> could probably go in UFC eventually.

FacetArea as in special function FacetArea?

There are all kinds of functionalities in dolfin::Cell:

  volume, diameter, normal, facet_area

which are neat functions to have within a more complex Expression.

> What we can do is create a dolfin::Cell from a ufc::cell (since we can
> access the cell index from the ufc::cell object) if we know that the
> ufc::cell comes from the mesh at hand.

How would a user access a dolfin::Cell from within eval?

Johan