[Dune] patch dune-grid r3316

[Carsten Graeser]

Dear Christian,

in the documentation on index- and idsets it reads:

   "Globally unique id: Every entity has a globally unique identification,
   i.e. across all levels, codimensions and processes. The type used for
   this id is user-defined. But: The copies in the refinement tree are
   identified which means e.g. an entity in the coarse grid that is copied
   to the fine grid has the *same* id."

The Doxygen page for the interface says, just as you mentioned,
entity!=entity' => id!=id' but later on:

   "An element is a copy of its father element if it is the only son.
   ... With respect to ids we define that  all copies of an entity share
   the same id."

I thought this is exactly what the test checks. Perhaps I missunderstood this.
Unfortunately the example image on the doxygen page, which might clarify this,
is missing.

Carsten

Christian Engwer schrieb:
> Dear Carsten,
> 
> cou applied patch to test whether copies of entities have the same
> global id. To me the grid interface reads such that these id's are
> required to be uniq and must be different.
> 
> It says if id==id' => entity==entity'. But in case of a copy it is not
> the same entity anymore, but only similar.
> 
> Therefor I think that your test tests the wrong thing.
> 
> Could the others please comment on this issue aswell, perhaps I
> misunderstood something.
> 
> Christian

-- 
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  Carsten Gräser

  Freie Universität Berlin
  FB Mathematik und Informatik (WE II)
  Arnimallee 2-6
  14195 Berlin, Germany

  office: +49-30 / 838-75349
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  email: graeser at math.fu-berlin.de
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