dolfin team mailing list archive

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

Anders Logg wrote:
> On Sun, Nov 02, 2008 at 06:29:25PM +0000, Garth N. Wells wrote:
> > Anders Logg wrote:
> > > On Sun, Nov 02, 2008 at 05:52:21PM +0000, Garth N. Wells wrote:
> > > > Do we want to insist that Dirichlet bc functions that do not appear 
> > > > inside a form are constructed with a FunctionSpace? DirichletBC is 
> > > > supplied with a FunctionSpace, so if the bc Function does not have a 
> > > > FunctionSpace, we could attach one automatically.
> > > >
> > > > Garth
> > > > _______________________________________________
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> > > I think this is already handled. Look in the Poisson demo. It uses a
> > > Constant to set the BC and it does not have a FunctionSpace attached
> > > to it. The DirichletBC class now uses its own FunctionSpace rather
> > > than the one that the Function has (if any). There is a check (in
> > > DirichletBC::check()) that checks that the FunctionSpace for the
> > > Function is the same as the one in the DirichletBC.
> > It works for Constant, but not for Functions. I was getting an error 
> > when Function::interpolate is called. Function::interpolate leads to 
> > eval being called, in which case there is a test for the FunctionSpace 
> > which fails. Constant provides its own eval and therefore doesn't have a 
> > problem.
> >
> > For now, I've added a test in DirichletBC for the FunctionSpace. What we 
> > can add is an attach function if there is no FunctionSpace associated.
> >
> > Garth
>
> In which demo does this show up? Is there a simple way I can comment
> something out to reproduce the error so I understand what goes wrong?

Look at /demo/nls/nonlinearpoisson/cpp.

If you change

  DirichletBoundaryCondition g(V, t);

to

  DirichletBoundaryCondition g(t);

it will break down.

Garth


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