- wait on block (r + 1)
- compute on block (r + 1)
- send block (r + 1) to rank (r + 1)
- Note that we must be careful when computing the begining of buffers and
+ Note that we must be careful when computing the beginning of buffers and
for send operations and computation we must compute the exact block size.
*/
send_to = (rank + 1) % size;