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. >>>>> >>>> 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 ;). Garth > Kristian? > _______________________________________________ DOLFIN-dev mailing list [email protected] http://www.fenics.org/mailman/listinfo/dolfin-dev
