Improve printing of MPI processes about fbpic HOT 2 CLOSED

I like this. I agree that the previous printed message was not very explicit.
Would you like to do a corresponding PR?

One thing to think about though is the case were we do single-proc simulation (esp. in the case where mpi4py is not installed): in this case it might be confusing for the user to see a message suggesting that MPI is used. I am wondering if the best, in the case, is to just print something like this:

• For single-proc:

Running fbpic-0.6.2 on CPU (using 4 threads)

• For multi-proc

Running fbpic-0.6.2 on CPU with 2 MPI processes (4 threads per MPI process)

What do you think?

from fbpic.

yes that makes sense, I'll do a PR

from fbpic.