# Hands-on: Message chain

Message chain using MPI
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In this exercise we explore a typical communication pattern, one-dimensional acyclic chain.

Source code for this exercise is located in mpi/message-chain/

Write a simple program where every MPI task sends data to the next one. Let
ntasks be the number of the tasks, and myid the rank of the current

• The message content is an integer array where each element is initialized to
myid.
• The sender prints out the number of elements it sends.
• Each receiver prints out their myid, and the first element in the received
array.
1. Implement the program described above using Send and Recv.
2. Use Sendrecv instead of Send and Recv when sending and receiving.
3. Can the code be simplified using MPI.PROC_NULL?
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