Hands-on: Collective operations
In this exercise we test different routines for collective communication.
Source code for this exercise is located in mpi/collectives/
First, write a program where rank 0 sends an array containing numbers from 0
to 7 to all the other ranks using collective communication.
Next, we continue with four MPI tasks with following initial data vectors:
| Task 0: | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
| Task 1: | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 |
| Task 2: | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 |
| Task 3: | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 |
In addition, each task has a receive buffer for eight elements and the values
in the buffer are initialized to -1. Implement a program that sends and
receives values from the data vectors to receive buffers using a single
collective communication routine for each case, so that the receive buffers
will have the following values. You can start from the skeleton fileskeleton.py.
Case 1
| Task 0: | 0 | 1 | -1 | -1 | -1 | -1 | -1 | -1 |
| Task 1: | 2 | 3 | -1 | -1 | -1 | -1 | -1 | -1 |
| Task 2: | 4 | 5 | -1 | -1 | -1 | -1 | -1 | -1 |
| Task 3: | 6 | 7 | -1 | -1 | -1 | -1 | -1 | -1 |
Case 2
| Task 0: | -1 | -1 | -1 | -1 | -1 | -1 | -1 | -1 |
| Task 1: | 0 | 1 | 8 | 9 | 16 | 17 | 24 | 25 |
| Task 2: | -1 | -1 | -1 | -1 | -1 | -1 | -1 | -1 |
| Task 3: | -1 | -1 | -1 | -1 | -1 | -1 | -1 | -1 |
Case 3
| Task 0: | 8 | 10 | 12 | 14 | 16 | 18 | 20 | 22 |
| Task 1: | -1 | -1 | -1 | -1 | -1 | -1 | -1 | -1 |
| Task 2: | 40 | 42 | 44 | 46 | 48 | 50 | 52 | 54 |
| Task 3: | -1 | -1 | -1 | -1 | -1 | -1 | -1 | -1 |
Tip: create two communicators
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