You can't use gather either. Same for gatherv, as you need to know the amount
you will receive in advance.
If I understand correctly your scenario (a random process is doing a broadcast
at random time steps), using MPI collectives is not the best approach as they
need global knowledge (there is
Oops,I think I meant gather not scatter...
I have a number of processes split into sender and receivers.
Senders read large quantities of randomly organised data into buffers for
transmission to receivers.
When a buffer is full it needs to be transmitted to all receivers this repeats
until all the data is transmitted.
Problem is that MPI
