In this exercise we test different routines for collective communication.
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 file skeleton.py.
| 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 |
| 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 |
| 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