[Dune] boundary id

[Oliver Sander]

Yes we have had boundaryId for a year, and the existing UGGrid
implementation seemed to be okay for everybody during this time...

How about a test for it for starters?

--
Oliver

************************************************************************
* Oliver Sander                ** email: sander at mi.fu-berlin.de        *
* Freie Universität Berlin     ** phone: + 49 (30) 838 75217           *
* Institut für Mathematik II   ** URL  : page.mi.fu-berlin.de/~sander  *
* Arnimallee 6                 ** -------------------------------------*
* 14195 Berlin, Germany        ** Member of MATHEON (www.matheon.de)   *
************************************************************************

On Tue, 12 Dec 2006, Christian Engwer wrote:

> Dear all,
>
>>> 2) boundary ids are a bit different since we have no iterators and
>>>  no index sets for boundaries - in fact no concept of boundaries in
>>>  Dune. It would be nice to at least be able to identify boundaries
>>>  without having to rely on world coordinate information. This is
>>>  why we introduce boundaryIDs for the boundary intersection. The
>>>  semantics is - as I understand it:
>>>  For each boundary intersection on the macro grid we can define an
>>>  id (>0?). During refinement we have: if a boundary intersection I
>>>  lies in a boundary intersection I_0 then it has the same boundary id
>>>  as id...
>>
>> I agree that it would be nice to have proper boundary handling.  But
>> I don't think that it is a good idea to add more intermediate
>> functionality two weeks before creating a release branch.  Also,
>> personally, I do not have the resources to do the necessariy
>> adaptations in UGGrid.
>
> Here I have to back Andreas. This is not an idea arising 2 weeks
> before release, but we agreed on that issue about one year ago.
>
> The specification of this is not very strict. It is just said that the
> grid should return an id. This id must not be user configurable. As it
> was said already yaspgrid supports this feature only in a very course
> manner. UG some how supports it aswell... you get an id... but both of
> these implementations require some extra work if you really want to
> use them.
>
> I would suggest that we stop discussion about whether the feature is
> usefull or not [remember we wanted to freeze the API ;-)], but we
> should try to figure out how much work a better implementaiton would
> require.
>
> Christian
>
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