Question

My program needs Process 0 to keep incrementing a counter and send messages until it receives a message from the last process in the program, which then have Process 0 decrement the same counter and send messages. I don’t know how to "Listen"/Poll whether a message has been received

My Case: (i is counter)

While Process 0 Has not received 0 from process 1, i++ and send message.

After Process 0 received the message, i– and send message.

Or in a more general sense:

While Process 0 has not received message from process 1, do A

After Process 0 has received the message from process 1, do B

How do I do this in MPI?

Thanks Alot!

Answer 1

Generally, you would use MPI_Isend, MPI_Irecv, and MPI_Test for polling. Read your book’s chapters on nonblocking communication.