Thus the basic (blocking) send has become:
MPI_Send( start, count, datatype, dest, tag, comm )and the receive:
MPI_Recv(start, count, datatype, source, tag, comm, status)The source, tag, and count of the message actually received can be retrieved from status.
Two simple collective operations:
MPI_Bcast(start, count, datatype, root, comm) MPI_Reduce(start, result, count, datatype, operation, root, comm)