ffc team mailing list archive

[Anders Logg <logg@xxxxxxxxx>]

On Fri, Jan 29, 2010 at 09:22:51PM +0100, Kristian Oelgaard wrote:
>
>
> On 29 January 2010 21:12, Anders Logg <logg@xxxxxxxxx> wrote:
> >On Fri, Jan 29, 2010 at 09:08:44PM +0100, Kristian Oelgaard wrote:
> >>
> >>
> >>On 29 January 2010 20:21, Anders Logg <logg@xxxxxxxxx> wrote:
> >>>On Fri, Jan 29, 2010 at 04:13:13PM +0100, Kristian Oelgaard wrote:
> >>>>I think it is almost there, but we need to rethink the way we
> >>>>manipulate the degrees of finite elements and forms, I think we have
> >>>>discussed this before but I don't recall if we ever reached a
> >>>>conclusion.  Try running the QuadratureElement.ufl demo.
> >>>
> >>>I don't see exactly what the problem is. Is it the automatic degree
> >>>selection?
> >>>
> >>>I've added some more debug output and the following is now printed for
> >>>the QuadratureElement demo:
> >>>
> >>> Found quadrature element(s) with the following degree(s): [3]
> >>> Selecting quadrature degree based on quadrature element: 3
> >>> quadrature_degree: auto --> 3
> >>>
> >>>That looks correct to me. Shouldn't this result in the same points
> >>>being chosen for both the QuadratureElement and the quadrature loop?
> >>
> >>I see now that it is only a problem for tensor representation. For
> >>the linear form the first term v*u*dx makes it a form of degree 4,
> >>and tensor representation will use that degree for the entire form
> >>if I remember correctly?
> >
> >Yes, and that's not much of a problem since it happens at compile
> >time.
>
> It is a problem if you try to tabulate a QuadratureElement with the wrong number of points :)
>
> >But for the FFC demo the representation is chosen as quadrature since
> >it involves quadrature elements, so if it fails it shouldn't be
> >related to tensor representation?
>
> Yes, for the bilinear form, for the linear form tensor is chosen, the degree is set to 4 and the problems begin.
>
> File "/home/oelgaard/software/fenics_branches/dev/ffc/tensor/monomialintegration.py", line 101, in _init_table
>    table[(ufl_element, None)] = fiat_element.tabulate(order, points)
>  File "/home/oelgaard/software/fenics_branches/dev/ffc/mixedelement.py", line 77, in tabulate
>    table = element.tabulate(order, points)
>  File "/home/oelgaard/software/fenics_branches/dev/ffc/quadratureelement.py", line 104, in tabulate
>    error("Points must be equal to coordinates of quadrature points")
>  File "<string>", line 1, in <lambda>
>  File "/home/oelgaard/software/fenics/ufl/ufl/log.py", line 124, in error
>    raise UFLException(self._format_raw(*message))
> ufl.log.UFLException: Points must be equal to coordinates of quadrature points
>
> Kristian

ok, I missed that! The automatic selection of representation should
check for quadrature elements and in that case use quadrature.

I'll fix it.

--
Anders

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