[Pw_forum] -nimage -npool -ntg -ndiag

[Eduardo Ariel Menendez Proupin]

Hi, I found in the new, or maybe not so new, users guide, that 1000 atoms or
so can be calculated, and new ways to paralelize.

The example in the manual is

 mpirun -np 4096 ./pw.x -nimage 8 -npool 2 -ntg 8 -ndiag 144 -input myinput.in

I have played a bit, but not with a massive computer, and I have found that
the default options are always better than my unexpert  choices.

So, I would like to see some hints, in addition to what  is reproduced below
(from the users guide), about the good choices of -ntg and -ndiag. Maybe
some examples is enough to understand it.