dolfin team mailing list archive

[Anders Logg <logg@xxxxxxxxx>]

On Mon, Nov 03, 2008 at 01:04:26PM +0000, Garth N. Wells wrote:
> DOLFIN wrote:
> > One or more new changesets pushed to the primary dolfin repository.
> > A short summary of the last three changesets is included below.
> > 
> > changeset:   5080:89eb83718857c7d9dbee0003a50983e28533243e
> > tag:         tip
> > parent:      5079:34987a77383c6b8a37a9c73d40ba4dc38115ca97
> > parent:      5078:1182f3401713488f72e0bc52f8031530bf192bd9
> > user:        Anders Logg <logg@xxxxxxxxx>
> > date:        Mon Nov 03 13:57:42 2008 +0100
> > files:       dolfin/fem/DirichletBC.cpp
> > description:
> > merge
> >
> 
> Beat me to it.
> 
> I'm running into an issue with DirichletBC and mixed elements because 
> BoundaryCondition, from which DirichletBC inherits, creates a new 
> FunctionSpace which messes up tests for equivalence and breaks the 
> sharing of function spaces paradigm.
> 
> Is there a problem if we remove SubDomain from the argument list for 
> DirichletBC and just pass the corerct FunctionSpace? One can easily 
> extract the necessary sub element FunctionSpace and send it to 
> DirihcletBC. To me this is more intuitive.
> 
> Garth

We then need to find a nice way for users to extract the "sub space".
Calling extract_sub_space, getting a pointer and then handling the
deletion of that pointer won't look very nice.

How about replacing the SubSystem class with a new class SubSpace
which works just like SubSystem but it also inherits from
FunctionSpace:

  SubSpace Vu(V, 0);
  SubSpace Vp(V, 1);

Then we can hide the call the extract_sub_space etc inside,
or rather the calls to extract_sub_element, extract_sub_dofmap.

-- 
Anders

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