Anders Logg wrote: > On Tue, Dec 01, 2009 at 09:41:04AM +0100, Marie Rognes wrote: >> Anders Logg wrote: >>> On Tue, Dec 01, 2009 at 09:15:53AM +0100, Marie Rognes wrote: >>>> Anders Logg wrote: >>>>> On Mon, Nov 30, 2009 at 11:01:59PM +0000, Garth N. Wells wrote: >>>>>> Anders Logg wrote: >>>>>>> We still haven't decided on the correct strategy for choosing the >>>>>>> degree of an unspecified element. >>>>>>> >>>>>>> What we have now looks at the total degree of the form and then sets >>>>>>> the degree accordingly. This doesn't really work weoull and the reason >>>>>>> is quite simple: We can't figure out the total degree correctly if we >>>>>>> don't know the degree of the coefficient. >>>>>>> >>>>>>> So my new suggestion is the following. We simply scan all elements in >>>>>>> the form with specified degrees and set the degree to the maximum >>>>>>> degree among the elements. >>>>>>> >>>>>> Or should it be the maximum degree of the test and trial functions? >>>>> Yes, that's basically what happens now. It looks at everything that >>>>> has a degree so it looks at the test and trial functions but also at >>>>> any coefficients that may happen to have a degree. >>>>> >>>>> That's useful for say v*f*g*dx if one of f and g happen to have a >>>>> degree specified. Then the degree for the other needs to be the same. >>>>> >>>> Why? >>> Since that's how the generated quadrature code works. It loops over >>> quadrature points for an integrand and then it's useful if everything >>> in the integrand is evaluated at those points. >>> >> Ok. > > I have made a new change of the selection strategy. >
Does the change in UFL affect the polynomial degree of the integrand as computed by UFL? I see that it's no longer taking into account derivatives, so if v and u1 are P1, will UFL tell the form compiler that dot(grad(v), grad(u)) is zero-order or second-order? > For quadrature, FFC now looks at the maximum degree of anything in the > form (including test and trial functions and coefficients). > > For tensor representation, FFC first looks at the maximum degree to > select the degree but then looks at the total degree to select the > quadrature it uses at compile time. > > I think this looks ok now and both FFC and UFL are ready for a new > release. There's still the bug fix Kristian is working on for using > quadrature elements for coefficients instead of Lagrange, but we > don't need to wait with the release. > OK. > FFC is still verbose about its selection of degrees so keep an eye on > what FFC prints during compilation and report any strange behavior. > Yes, good to keep it on initially. Garth > -- > Anders > > > ------------------------------------------------------------------------ > > _______________________________________________ > Mailing list: https://launchpad.net/~dolfin > Post to : [email protected] > Unsubscribe : https://launchpad.net/~dolfin > More help : https://help.launchpad.net/ListHelp _______________________________________________ Mailing list: https://launchpad.net/~ffc Post to : [email protected] Unsubscribe : https://launchpad.net/~ffc More help : https://help.launchpad.net/ListHelp
