[Dune] IntersectionIterator Umbau heute.

[Christian Engwer]

Hallo,

> Damit das Ganze generisch verwendbar bleibt, schlage ich folgendes vor:
> 
> wir fügen noch eine dritte Methode ein, nämlich ibegin, welche mit einem
> template Parameter versehen wird, sowas wie level und leaf, um die
> IntersetctionIteratoren selektieren zu können. Damit hat man dann
> zumindest die Möglichkeit, Code zu schreiben, welcher zwischen beiden
> IntersectionIteratoren switchen kann.
> 
> Meinungen und Vorschläge hierzu?

Ich think just the one or the other. We should not add several
interfaces which are doing the same.

I see the problem, that ileafbegin and ilevelbegin don't really fit to
the generic usage we achieved with the indexsets. Actually we do have
a far more general problem. What we have is that we offer different
views for different subsets of our entities. Some properties in our
grid are not specific to an entity (which is unique to all views), but
to a single view. Examples for such properties are the indicies, the
interators and also the intersections.

Someone (I think it was Andreas) once proposed to add ibegin/iend to
the indexsets and keep the generality in that one place. For
level/leaf this isn't really a problem, because we have the
intersections anyway, but introducing this method into the indexset
interface would raise big problems for the creation of alternative
indexsets.

I don't have a real conclusion yet, but we should first think about
the consequences, because we will then have to live with this
interface for a while.

Christian