dolfin team mailing list archive

[Anders Logg <logg@xxxxxxxxx>]

On Fri, Jan 28, 2011 at 11:37:23AM +0000, Garth N. Wells wrote:
>
>
> On 28/01/11 11:33, Mehdi Nikbakht wrote:
> > On Fri, 2011-01-28 at 11:25 +0100, Andre Massing wrote:
> >> Den 28.01.11 00.30, skrev Anders Logg:
> >>> On Thu, Jan 27, 2011 at 11:10:08PM +0100, Anders Logg wrote:
> >>>> I would like to add factory functions in UFC, in particular
> >>>>
> >>>>    finite_element* finite_element::create() const;
> >>>>    dof_map* dof_map::create() const;
> >>>>
> >>>> Are there any objections to this? It would be easy to add and easy to
> >>>> implement in FFC.
> >>>>
> >>>> I need it to implement refinement of FunctionSpaces in DOLFIN where
> >>>> fresh copies of ufc::finite_element and ufc::dof_map are needed given
> >>>> a ufc::finite_element or ufc::dof_map.
> >>>>
> >>>> An alternative is to hack create_sub_foo so that it returns a copy of
> >>>> the element/dofmap itself if the component argument 'i' is>= the
> >>>> number of sub elements/dofmaps.
> >>>
> >>> I suggest we add this to UFC 1.6 and make a release next week together
> >>> with DOLFIN 0.9.10, FFC 0.9.5 + other packages that need release. The
> >>> sooner the better: there will be time to make bug fix releases and
> >>> things will be tested before 1.0 in March.
> >>>
> >>> If there are any other things we want to add to UFC, now's a good
> >>> time.
> >>
> >> What about the tabulate_tensor function taking arguments for runtime
> >> quadrature rules, as we discussed a while ago? ATM I hacked UFC and my
> >> generated form files having an additional function
> >>
> >> virtual void tabulate_tensor(double* A,
> >>                               const double * const * w,
> >>                               const ufc::cell& c,
> >> 			     dolfin::uint num_quad_points,
> >> 			     const double * const * coordinates,
> >> 			     const double * weights) const
> >>
> >> Such an interface would add a flexible layer for those who wants to have
> >> some type of runtime quadrature.
> >>
> >> General opinons about that?
> >
> > Although this makes life easier for the case that we have to compute
> > quadrature rule in the run-time, but the current interface can also
> > handle this problem.  You can derive a class form ufc::foo_integrals and
> > pass object containing new gauss quadrature rule to its constructor as
> > we do for partition of unity method.

How is that possible? I assume you make a subclass and implement the
tabulate_tensor functions yourself using the points given in the
constructor. That's fine, but the point here would be that FFC
generates the code for us and the generated code would use the
quadrature points.

> I think that the proposed interface change would make the above process
> simpler.

If we agree it's a good interface, we could put it in now for 1.6. It
will make it easier once we implement since no change in UFC will be
needed at that point.

--
Anders