Dear Jess,
Thanks very much for your kind reply. It is of great help.
initial_spin = InipialSpin(scaled_spins=[1.0, 1.0, 0.0, 0.0, -1.0, -1.0])
the scale factor specified by scaled_spins is used to scale the initial guess. If there is no initial guess, then it represents the scale factor of the maximum magnetic moment of the atom.
Now I understand why the converged FM can be used as a good initial of AFM configuration.
Thanks very much.
Guangping