ffc team mailing list archive

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

Quoting Shawn Walker <walker@xxxxxxxxxxxxxxx>:

> The Poisson.h file I was refering to is generated by FFC.
>
> I guess I will wait until the FFC generated form.h files include the quad
> point locations in a comment.  Just to make sure there is no mismatch.

This has been added.

Kristian

> - Shawn
>
> On Tue, 23 Jun 2009, Martin Sandve Alnæs wrote:
>
> > If you're looking at SFC generated code, there
> > is no such thing as quad rules in the Poisson.h file.
> > Thus it is unclear to me what you're doing now.
> >
> > There may be a translation and scaling of the
> > rules from the .py file to the generated code.
> > I think the source rules are defined on [-1, 1]
> > as opposed to the UFC reference cell on [0, 1].
> >
> > The generated *_integral*.cpp code should have
> > the scaled quad rules embeddded as arrays.
> >
> > Martin
> >
> >
> > On Mon, Jun 22, 2009 at 11:33 PM, Shawn Walker<walker@xxxxxxxxxxxxxxx>
> wrote:
> >> Alright.  I'm looking at these quad rules, the 4-pt rule doesn't match the
> >> weights that show up in the Poisson.h file I have right now.  Also, the
> >> coordinates seem weird.  Are all of these points evaluated outside the ref
> >> triangle?
> >>
> >> - Shawn
> >>
> >> On Mon, 22 Jun 2009, Martin Sandve Alnæs wrote:
> >>
> >>> SFC doesn't use the same quadrature rules as
> >>> FFC, so that makes no sense in my head.
> >>> Either install SyFi properly with dependencies,
> >>> or keep using FFC and ignore my suggestion.
> >>>
> >>> (If you still want them, the rules SFC use are in
> >>> site-packages/sfc/quadrature/quad_tables.py)
> >>>
> >>> Martin
> >>>
> >>>
> >>>
> >>> On Mon, Jun 22, 2009 at 11:09 PM, Shawn Walker<walker@xxxxxxxxxxxxxxx>
> >>> wrote:
> >>>>
> >>>> Actually, would it be possible for you to just give me the 4-pt quad
> rule
> >>>> on
> >>>> a triangle.  The problem is, I don't have GiNAC setup, which is needed
> to
> >>>> run SyFi, right?
> >>>>
> >>>> - Shawn
> >>>>
> >>>> On Mon, 22 Jun 2009, Martin Sandve Alnæs wrote:
> >>>>
> >>>>> Ok. Temporarily, maybe you'll be happy with the code
> >>>>> generated by SFC (see the demo/*/cpp/ directories in SyFi).
> >>>>> There both weights and points are embedded directly in the code.
> >>>>>
> >>>>> Martin
> >>>>>
> >>>>>
> >>>>>
> >>>>> On Mon, Jun 22, 2009 at 10:50 PM, Shawn Walker<walker@xxxxxxxxxxxxxxx>
> >>>>> wrote:
> >>>>>>
> >>>>>>
> >>>>>> On Mon, 22 Jun 2009, Anders Logg wrote:
> >>>>>>
> >>>>>>> I think Shawn just wants to get the quadrature points so he can
> >>>>>>> hand-modify the code for tabulate_tensor to handle higher-order
> mapped
> >>>>>>> elements (to make a prototype for higher-order elements).
> >>>>>>>
> >>>>>>> Correct me if I'm wrong.
> >>>>>>
> >>>>>> Yes!
> >>>>>>
> >>>>>>> In that case, we won't need to make them available since they are
> >>>>>>> available to the form compiler when the code is being generated, but
> >>>>>>> it would help if they were available in a comment in the generated
> >>>>>>> code.
> >>>>>>
> >>>>>> I agree that having them in a comment would be good.
> >>>>>>
> >>>>>> - Shawn
> >>>>>>
> >>>>>>>
> >>>>>>> On Mon, Jun 22, 2009 at 10:28:29PM +0200, Martin Sandve Alnæs wrote:
> >>>>>>>>
> >>>>>>>> On Mon, Jun 22, 2009 at 9:10 PM, Kristian
> >>>>>>>> Oelgaard<k.b.oelgaard@xxxxxxxxxx> wrote:
> >>>>>>>>>
> >>>>>>>>> Quoting Shawn Walker <walker@xxxxxxxxxxxxxxx>:
> >>>>>>>>>
> >>>>>>>>>> Actually, I am still a little confused.  Whenever you compute an
> >>>>>>>>>> integral
> >>>>>>>>>> by quadrature, you need to evaluate the integrand at the
> quadrature
> >>>>>>>>>> points.  Those are the points I need.
> >>>>>>>>>
> >>>>>>>>> If you have a quadrature element in your form
> >>>>>>>>>
> >>>>>>>>> element = FiniteElement("Quadrature", triangle, 2)
> >>>>>>>>>
> >>>>>>>>> you can call the
> >>>>>>>>> tabulate_coordinates() function of the dof_map associated with the
> >>>>>>>>> quadrature
> >>>>>>>>> element. If you don't have a quadrature element there is no direct
> >>>>>>>>> way
> >>>>>>>>> of
> >>>>>>>>> getting the quadrature points.
> >>>>>>>>>
> >>>>>>>>>> I just need the quad rule that is used in a particular case.  I
> see
> >>>>>>>>>> the
> >>>>>>>>>> weights are defined in the tabulate_tensor routine.  Are the
> points
> >>>>>>>>>> listed
> >>>>>>>>>> in a comment somewhere?
> >>>>>>>>>
> >>>>>>>>> No, currently not. But it might be a natural thing to have. I'll
> >>>>>>>>> look
> >>>>>>>>> into it.
> >>>>>>>>
> >>>>>>>> It could be an idea to make it available through UFC,
> >>>>>>>> but then again each ufc::*_integral may use different
> >>>>>>>> quadrature rules for different terms...
> >>>>>>>> However, an exception can be thrown if there is no unique rule in
> >>>>>>>> use.
> >>>>>>>>
> >>>>>>>> Martin
> >>>>>>>> _______________________________________________
> >>>>>>>> FFC-dev mailing list
> >>>>>>>> FFC-dev@xxxxxxxxxx
> >>>>>>>> http://www.fenics.org/mailman/listinfo/ffc-dev
> >>>>>>
> >>>>>> _______________________________________________
> >>>>>> FFC-dev mailing list
> >>>>>> FFC-dev@xxxxxxxxxx
> >>>>>> http://www.fenics.org/mailman/listinfo/ffc-dev
> >>>>>>
> >>>>>>
> >>>>>
> >>>>
> >>>
> >>
> >
> >