Example
Parallel output of a message
Example Current Practice #1 is a do-nothing program that initializes itself, and refers to the ``all'' communicator, and prints a message. It terminates itself too. This example does not imply that MPI supports printf-like communication itself.
Example
Message exchange (supposing that size is even)
Example Current Practice #1 schematically illustrates message exchanges between ``even'' and ``odd'' MPI processes in the ``all'' communicator.