1 | Consider for example, shift to right |
2 |
Then Processors 0 .. Nproc-2 Send to right
|
3 | We can't necessarily send all messages and then receive all messages. "Standard" send can be "blocking" i.e. will not return unless receive completed by destination processor. In this case, we can deadlock as all "hang" after send, waiting for receive |
4 | So we are more careful |