[Dune] Questions about the grid parts

[Oliver Sander]

Dear Dune!
I have a few questions concerning the grid parts (in dune-grid).
I'd be grateful if someone could answer them for me.

a) What does the HierarchicGridPart do, as opposed to the
    LeafGridPart?  They seem to have identical documentation.

b) LeafGridParts have a method level().  I wonder what the
    design decision was to include that.  GridParts claim to
    encapsulate fairly arbitrary subsets of entities, and such
    subsets can't really be expected to have a level, can they?

c) The LeafGridPartTraits class doesn't return the grids
    leaf index set type, when asked for the appropriate index
    set type, but a WrappedLeafIndexSet<GridType>.  What
    is that?

thanks for the help,
Oliver

-- 
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* Oliver Sander                ** email: sander at mi.fu-berlin.de        *
* Freie Universität Berlin     ** phone: + 49 (30) 838 75217           *
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