ufl team mailing list archive

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

Quoting "Garth N. Wells" <gnw20@xxxxxxxxx>:

> 
> 
> Anders Logg wrote:
> > On Mon, Feb 16, 2009 at 09:57:26AM +0100, Martin Sandve Alnæs wrote:
> >> On Sun, Feb 15, 2009 at 10:10 PM, Anders Logg <logg@xxxxxxxxx> wrote:
> >>> On Fri, Feb 13, 2009 at 02:30:00PM +0100, Martin Sandve Alnæs wrote:
> >>>> Attaching metadata to an integral is implemented, but we
> >>>> haven't  decided what format the metadata should be in.
> >>> I think there needs to be a convention as part of UFL for how to
> >>> specify the integration rule. Otherwise different form compilers will
> >>> invent different conventions and interpret the metadata differently.
> >> Agree.
> >>
> >>> Here's a suggestions:
> >>>
> >>>  metadata = ("quadrature", degree)
> >>>  metadata = ("tensor", degree)
> >> Here you're already into FFC territory...
> >>
> >> Integration order is an important mathematical
> >> property, the method for code generation is not.
> >> "tensor" is in the latter category.
> > 
> > Hints for the degree of the quadrature is also form compiler
> > specific. There may be other ways to evaluate the integral than
> > quadrature, for example by random sampling, symbolic integration (like
> > in SyFi) or using a tensor representation (FFC).
> >
> 
> Tensor representation still uses quadrature, it's just that it's 
> performed a priori rather than at runtime.

I guess the degree is just the highest polynomial order that the user wishes
integrated exactly.
If it is possible for the form compiler to comply with this wish it may do so,
if not it will ignore the instruction.
On second thought, I think we do need 'quadrature', 'tensor' to be allowed in
the metadata, otherwise the user can't specify different representations on
different subdomains.

Kristian
 
> Garth
> 
> > 
> > 
> > ------------------------------------------------------------------------
> > 
> > _______________________________________________
> > UFL-dev mailing list
> > UFL-dev@xxxxxxxxxx
> > http://fenics.org/mailman/listinfo/ufl-dev
> 
> 
> _______________________________________________
> UFL-dev mailing list
> UFL-dev@xxxxxxxxxx
> http://fenics.org/mailman/listinfo/ufl-dev
>