MatGetSubMatrix question

Jed Brown jed at
Mon May 25 08:20:01 CDT 2009

Is it really necessary that iscol be a sequential index set that covers
all columns, with csize selecting the local columns?  I realize this
might be natural/easy for AIJ formats, but it feels clumsy (not to
mention not scalable due to the ISAllGather).

I'm guessing this is a relic from when IS was not a real parallel
object.  Am I missing some deep reason for this interface, or could
iscol be parallel and csize be dropped?


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