Guess I should have kept quiet a bit longer. As I recall we had
already seen a counter example to Jeff's stronger statement and that
motivated my narrower one.
If there are no wildcard receives - every
MPI_Barrier call is semantically irrelevant.
Do you have a counter example for my more cautious assertion?
No, but my momentary interest included wildcards, and it seemed to me
that, as a corollary to your claim, that if there are wildcards, then
Barriers could be relevent. And my example was "proof by
( I had already granted that a correct MPI program could
be made incorrect with a barrier and the barrier that broke it would
have to be considered be "semantically relevant". I would reword the
statement with that in mind if I were to offer it up again. )