ffc team mailing list archive

[Anders Logg <logg@xxxxxxxxx>]

On Mon, Mar 22, 2010 at 11:41:42AM +0100, Marie Rognes wrote:
> Anders Logg wrote:
> >On Mon, Mar 22, 2010 at 06:20:00PM +0800, Garth N. Wells wrote:
> >>On 22/03/10 16:42, Kristian Oelgaard wrote:
> >>>On 21 March 2010 21:32, Anders Logg <logg@xxxxxxxxx> wrote:
> >>>>After Marie's latest addition of enriched spaces (and some discussion
> >>>>with Doug Arnold), it seems clear that our current notation V + W for
> >>>>mixed spaces is not optimal.
> >>>>
> >>>>Even though one may think of the operation of creating a "mixed
> >>>>function space" as a direct sum,
> >>>>
> >>>>X = {(v, 0) : v in V} \oplus {(0, w) : w in W},
> >>>>
> >>>>it is more natural (and common) to think of it as a Cartesian product,
> >>>>
> >>>>X = V \times W = {(v, w) : v in V, w in W}
> >>>>
> >>>>It would therefore be more natural to use '*' instead of '+' as the
> >>>>operation for creating mixed elements/function spaces.
> >>>>
> >>>>That would free up '+' to be used for enriched spaces (which have
> >>>>recently been added),
> >>>>
> >>>>X = {v + w : v in V, w in W}
> >>>>
> >>>>The typical example would be to take V piecewise linears and W scaled
> >>>>P3 bubbles.
> >>>>
> >>>>In summary, the suggestion is to use the following notation:
> >>>>
> >>>>+ <-->  +
> >>>>* <-->  \times
> >>>>
> >>>>It's obvious this is better than what we have now which is
> >>>>
> >>>>+ <--> \oplus
> >>>>? <--> +
> >>>>
> >>>>Thoughts?
> >>>Agree.
> >>>
> >>Me too.
> >>
> >>Garth
> >
> >ok. Let's change then.
> >
> >It will require changes in both UFL and FFC. Anyone up for it?
>
> I can fix ffc.

I was hoping for that. :-)

> (Have no permission for ufl)

You do now. ;-)

--
Anders

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