I am digging through openmpi to find out what algorithm the barrier
seems to be bruck/dissemination.
However i stumbled upon something odd.
I think you intend (by the comments and the function name) to send to the
previous node and receive from the next. But actually it looks like you are
doing the reverse. (which should then be the dissemination algorithm)
It's no big deal, I'm just a bit confused right now, and wonder if I'm
missing something. I hope you can help me understand.