[Dune] Dune::GlobalUniversalMapper< G > usage and semantics ???

[Peter Bastian]

Dear Benedikt,

The answer is no, it doesn't provide a globally unique index. What it does is 
to map an ID (which is either globally unique or unique per processor) to a 
consecutive index within a single process.
Therefore you just call the contains method once for each entity (in each 
process) that you want to map to an array and then you can use it. By that 
method you can attach data to any subset of entities which is not possible 
with the index-based mappers.

Hope that answers it?

-- Peter

Am Freitag, 27. Juni 2008 09:42 schrieb Benedikt Oswald:
> As somehow my mail went unnoticed, I dare to resend it:
>
>
> Dear Dune developers, re. the use of the global universal mapper in Dune:
>
> does this class provide an array index (consecutive, starting from zero)
> of grid entities and subentities, depending on the codimension,
> over all processes in a parallel, MPI context ?
>
> Can I use this class to map, e.g. an id of an edge in ALUGrid
> onto an array and get the same index on two different processes
> if the id refers to the same edge, shared by these processes ?
>
> Perhaps I am little bit complicated, but the background is in
> addressing matrix and vector entries of a parallel linear algebra
> package, such as e.g. trilinos.
>
> Thanks for some enlightment, Benedikt

-- 
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Peter Bastian
Institut fuer Parallele und Verteilte Systeme
Abteilung Simulation grosser Systeme
Universitaet Stuttgart
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email: Peter.Bastian at ipvs.uni-stuttgart.de
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