The charge flipping algorithm

Oszlányi, G.; Sütő, A.

doi:10.1107/S0108767307046028

Figure 6
$[F_{o}+\Delta F]$ relaxation of the modulus constraint in the charge flipping algorithm. A selected structure factor before and after this step [ $[G({\bf h}) \rightarrow F({\bf h})]$ ] is plotted by empty and red symbols in the complex plane for a few possible cases. The measured $[F_{\rm obs}({\bf h})]$ defines the radius of the (bold) circle that is the centre of the mirror operation and the parameter W defines a (shaded) ring that limits the change of the modulus.