MatGetSubMatrix question

[Jed Brown]

Lisandro Dalcin wrote:

> unless things have changed very recently (after 3.0.0 release), IS is
> far from being a real parallel object.

What exactly do you mean by this?  It has a parallel communicator and
collective operations.  ISGetIndices gives you just the local indices,
with size given by ISGetLocalSize, but ISGetSize gives you the global
size, ISInvertPermutation is collective (not scalable, but that's
another issue), etc.  The row IS given to MatGetSubMatrix is parallel.

Jed

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