dolfin team mailing list archive

["Garth N. Wells" <gnw20@xxxxxxxxx>]

Anders Logg wrote:
> On Tue, Dec 16, 2008 at 02:19:38PM +0000, Garth N. Wells wrote:
> > Anders Logg wrote:
> > > On Tue, Dec 16, 2008 at 02:20:22PM +0100, Martin Sandve Alnæs wrote:
> > > > If I subclass Function and implement eval, then
> > > > call vector() on an object of my class, a vector
> > > > is created but initialized to zero. I would rather
> > > > expect that the function is evaluated in the function space:
> > > >
> > > > GenericVector& Function::vector()
> > > >  {
> > > >    // Initialize vector of dofs if not initialized
> > > >    if (!_vector)
> > > > +  {
> > > >      init();
> > > > +    interpolate(*_vector, *_function_space);
> > > > +  }
> > > >
> > > >    dolfin_assert(_vector);
> > > >    return *_vector;
> > > > }
> > > Looks like a good idea. Can you add it?
> > >
> > > > But I'm not sure what kind of side effects this can have on other code?
> > > >
> > > > Martin
> > > I don't think it will have more side effects than what we have now
> > > when we just create a zero vector.
> > Interpolate is tricky because not all functions (e.g. DG) are 
> > interpolated sensibly. This issue pops up in the VTK io.
> >
> > Garth
>
> I don't think that's a problem here. The interpolation will be into
> the appropriate function space, which for a DG function is a DG space,
> so for DG0, the vector will contain one value for each cell.

DG(k), k > 0 is the problem.

Garth

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