Quoting "Garth N. Wells" <[email protected]>: > > > Anders Logg wrote: > > On Fri, Apr 17, 2009 at 03:57:09PM +0800, Garth N. Wells wrote: > >> > >> Anders Logg wrote: > >>> On Fri, Apr 17, 2009 at 03:07:17PM +0800, Garth N. Wells wrote: > >>>> Anders Logg wrote: > >>>>> On Fri, Apr 17, 2009 at 08:59:43AM +0200, Johan Hake wrote: > >>>>>> On Friday 17 April 2009 03:32:26 Garth N. Wells wrote: > >>>>>>> Should we start moving to UFL-based forms for the DOLFIN demos? Is > the > >>>>>>> only serious outstanding issue on the FFC side the correct > determination > >>>>>>> of the quadrature order? > >>>>>> Not sure how this could be best done in PyDOLFIN. > >>>>>> > >>>>>> We could add > >>>>>> > >>>>>> from dolfin.ufl import * > >>>>>> > >>>>>> after each > >>>>>> > >>>>>> from dolfin import * > >>>>>> > >>>>>> in the demos. When this is done and it all just works(TM) we can move > the > >>>>>> files in the site-packages/dolfin/ufl directory down to > site-packages/dolfin, > >>>>>> and remove > >>>>>> > >>>>>> from dolfin.ufl import * > >>>>>> > >>>>>> from the demos? > >>>>>> > >>>>>> Johan > >>>>> I suggest we just move everything to UFL at once and then solve any > >>>>> problems that we encounter. > >>>>> > >>>>> I'm intending to remove the .form support from FFC quite soon (maybe > >>>>> today). > >>>>> > >>>>> It's easier to fix things so that they work with UFL than to have two > >>>>> conflicting form languages work at the same time.
I agree on this. > >>>> The quadrature issue is serious, so I think that it should be tackled > >>>> before the transition, or at least a short-term plan for how to solve it > >>>> should be in place. > >>>> > >>>> Garth > >>> Is it so serious? It's a small thing compared to what will happen when > >>> the .form support is removed from FFC (as in everything will be broken > >>> until fixed). > >>> > >> Results computed with the new and old formats will not, in general, be > >> the same, so I considered it to be serious. > > > > Yes, they won't be the same but I thought they would still be correct > > (as in possibly using a better quadrature rule than needed). > > > > No, it uses a lower degree of quadrature. For example, for the Poisson > demo using the new UFL format only one quadrature point is used for the > source term, whereas enough points for a quadratic polynomial are required. > > Not quite sure what 'not the same but still correct' means ;). As far as I can tell the current implementation in UFL will result in a sufficient degree of quadrature being used. Kristian > Garth > > > > Kristian? > > > > > _______________________________________________ > FFC-dev mailing list > [email protected] > http://www.fenics.org/mailman/listinfo/ffc-dev > _______________________________________________ DOLFIN-dev mailing list [email protected] http://www.fenics.org/mailman/listinfo/dolfin-dev
