convergence criteria for SCF and structural optimization

[hqzhou]

Hi, Francois,

It seems there are no thresholds existed for checking convergence of energy and force
in qbox. It's quite different from other code, for example, PWscf, VASP. Does this mean
that we must do tests to determine the appropriate niter, nitscf in case of ion dynamics
and/or scf calculation involved?

Thanks!

zhou huiqun
@earth sciences, nanjing university, china