[Dune] Re: Notification from Dune

[Christian Engwer]

Hi Dune,

I am the one who marked this task 1.0

> FS#120 - Inconsistent numbering of the vertices of the reference quad
> User who did this: - Robert Klöfkorn (robertk)
> 
> ----------
> If this is not considered critical, I would like to mark this task for
> post 1.0. 

We discussed this issue in Stuttgart and we decided, that this issue
must be solved before 1.0 in the one ore other way. Oliver complains,
that the faces in the reference quad are oriented with some normal
vectors pointing outwards and some pointing inwards.

We agree, that it would be nice to have all normalvectors pointing
inwards (like in the reference triangle). The current orientation
arises from the fact, that the reference cubes are constructed via
tensor product.

None of us three, participating in the discussion, wrote the code or
knew the details, so we could not say how difficult it would be to
change this behaviour.

If it is managable, we should do this change before 1.0, because
changing the semantics of the reference cube after 1.0 would be a
really bad idea; the api would stay the same and no user whould be
warned to change his code. Really strange and hard to find errors
would be the result.

If it is to hard to implement we should just close the bug as "won't
fix".

Anyway we should come to a decission before 1.0, because changes to
the semantics of the reference elements after 1.0 are dangerous.

Perhaps Peter can say a little bit about the reasons for this
numbering and about the required amount of work for the demanded
changes.

Cheers Christian