ffc team mailing list archive

[Kristian Oelgaard <k.b.oelgaard@xxxxxxxxx>]

On 29 January 2010 13:11, Marie Rognes <meg@xxxxxxxxx> wrote:
> Kristian Oelgaard wrote:
> > On 29 January 2010 01:23, Anders Logg <logg@xxxxxxxxx> wrote:
> > > There seem to be just a couple of issues remaining in order of
> > > importance:
> > >
> > > 1. QuadratureElement
> > >
> > > 2. DOLFIN fem unit test
> > >
> > > 3. evaluate_basis_derivatives
> > >
> > > 4. RestrictedElement
> > >
> > > Among these, I would say 1-2 are crucial to fix before 0.9.0,
> > > but 3-4 are less crucial.
> > >
> > > It would be good to have evaluate_basis_derivatives working, but I
> > > don't know how much work is involved.
> >
> > First my apologies for the late reply, Internet was down again all morning
> > and it pisses me off.
> >
> > Now that BDM elements also compiles for gcc it looks like everything is in
> > place for evaluate_basis.
> > CG and CR elements work, and so does all linear elements and DG constants.
> > 2nd and 3rd order elements of BDM, RT, and DG type does not give the same
> > result but there are explanations for this and at least it looks like they
> > agree with the values you would get from FIAT if you tabulate on the
> > reference element.
> >
> > evaluate_basis_derivatives works for CG elements and for most elements of
> > degree 1.
> >
> > I'm working on some kind of unit testing framework for evaluate_basis and
> > evaluate_basis_derivatives, such that we can make sure that at least cpp
> > code and FIAT agrees on the reference element. If this test works, then the
> > only bug can be in the transformation back to the physical element, but
> > since this works for CG elements I don't see why it shouldn't for other
> > elements too.
> > However, I'll put this development on hold until Quadrature and Restricted
> > elements work.
> >
> > > RestrictedElement is also good to have, but I would say it is less
> > > important, especially since it's unclear what exactly it should do and
> > > how it should be implemented.
> >
> > It should be implemented like I did it in the old FFC :)
> > w.r.t. the demo, it should test if restrictions on a MixedElement are
> > propagated to the sub elements and that a restricted element can appear in a
> > MixedElement.
>
> I'm taking care of RestrictedElement (onto facets/cells etc) at ze moment.

OK, I'll do Quadrature then.

Kristian


> --
> Marie
>
> > > We should also have the following in mind:
> > >
> > > (i) The number of users relying on restricted elements is most likely
> > > very small and they are very likely using the development version
> > > anyway so if a fix for restricted elements comes next week, that will
> > > be ok.
> > >
> > > (ii) If we make a release of 0.9.0 now and package it for Debian/Ubuntu,
> > > it is still possible to request Ubuntu to pull bug fixes for some
> > > time. So we can release 0.9.0 now and then 0.9.1 in a couple of weeks.
> >
> > I think this sounds like a good plan. I'll work on getting
> > QuadratureElement up and running and the RestrictedElement.
> > If there are any bugs in evaluate_basis_derivatives we'll release it in
> > 0.9.1.
> > The code really needs some cleaning up, and we should also rearrange some
> > of the utility functions, but that can wait until 0.9.1.
> >
> > Kristian
> >
> > > One of the reasons I'm pressing on with the release is the interface
> > > changes that we have made in both FFC and DOLFIN. It would be good to
> > > introduce these as early as possible to avoid confusion about how to
> > > write a form file (Coefficient, not Function) and how to implement
> > > Expressions (Array, not std::vector).
> > >
> > > --
> > > Anders
> > >
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> > >
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