ffc team mailing list archive

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

Quoting Kristian Oelgaard <k.b.oelgaard@xxxxxxxxxx>:

> Quoting Peter Brune <prbrune@xxxxxxxxx>:
>
> > Some recent discussions and problems that have cropped up have led me to
> > need/want to add some specialized quadrature rules to FFC.  These include
> > "optimal" combinatorially-derived rules for given order polynomials for the
> > n-simplex, as well as rules that can be explicitly guaranteed to have
> > certain properties (positivity, all-internal-nodes, etc)
> >
> > Does anyone else need anything like this?  I already have implementations
> of
> > a few nice rules for higher-dimensional applications, but have started to
> > adapt them for this purpose.  Ideally we would be able to specify a rule in
> > the ffc command.  I'm looking at where to put this.
>
> So on the command line we should be able to do:
>
> ffc --quadrature-rule some_string
> or
> ffc -q some_string
>
> and then in the file ffc/fem/quadrature.py in the function
> make_quadrature() there should be an extra argument
>
> make_quadrature(shape, n, quad_rule)
>
> with default None? Then you can just put your code and some switches in this
> file.
> I can add the command line option and propagate it to the make_quadrature()
> function, at least for quadrature representation, if nobody objects.

I added this to FFC, just add your rules to the make_quadrature() function.

Kristian

>
> > There are other potential benefits to this move.  If we were to switch to
> > rules we have definite information about, we could use, say, group symmetry
> > properties, combined with symmetry properties of the unknowns, for further
> > optimization of the form compilation by quadrature.  We would already win,
> > especially in 3D, by getting away from the squashed rules and towards rules
> > that are more optimal.
>
> This would be nice.
>
> Kristian
>
> > - Peter
> >
>
>
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