[dune-pdelab] [dune-pdelab-commit] [Commit] dune-pdelab - 043f015: [LocalFunctionSpace] Export subspace depth for LFSIndexCache

[Christian Engwer]

Hi Steffen,

>     [LocalFunctionSpace] Export subspace depth for LFSIndexCache
>     
>     Due to the recent changes to the way subspaces work, the LFSIndexCache
>     needs to know how the length of the path from the subspace to the root
>     of the underlying tree because it needs to remove that portion of the
>     treeindex before invoking the orderings for the subtree (those expect
>     to get a shorter DOFIndex than what we have right now, as we have cut
>     off the upper part of the tree in the subspace).
>     
>     This patch adds a new method subSpaceLength(), which returns 0 for
>     regular LocalFunctionSpaces and a positive value for the root
>     LocalFunctionSpace of the LocalFunctionSpace tree generated from a
>     GridFunctionSubSpace.

I'm not quite sure that this does what we want?! Shouldn't we reuse
the ordering of the root-node? If we strip parts of the DOFIndex and
then use only a reordering on this subtree, how will I access a global
vector or matrix?

I guess I just didn't understand the implications correctly, but it
seems to me, that this patch will introduce the same problem I
experienced with the DOFIndex at the level of the reordered index?!

Ciao
Christian