The Hamilton generalized R factor for all reflections
that satisfy the resolution limits established by
_refine_analyze.RG_d_res_high and
_refine_analyze.RG_d_res_low and for those
reflections included in the working set when a free R set
of reflections is omitted from the refinement.
sum_i sum_j w_{i,j}(|Fobs|_i - G|Fcalc|_i)(|Fobs|_j - G|Fcalc|_j)
RG = Sqrt( ----------------------------------------------------------------- )
sum_i sum_j w_{i,j} |Fobs|_i |Fobs|_j
where
|Fobs| = the observed structure-factor amplitudes
|Fcalc| = the calculated structure-factor amplitudes
G = the scale factor which puts |Fcalc| on the
same scale as |Fobs|
w_{i,j} = the weight for the combination of the reflections
i and j.
sum_i and sum_j are taken over the specified reflections
When the covariance of the amplitudes of reflection i and
reflection j is zero (i.e. the reflections are independent)
w{i,i} can be redefined as w_i and the nested sums collapsed
into one sum.
sum_i w_i(|Fobs|_i - G|Fcalc|_i)2
RG = Sqrt( ----------------------------------- )
sum_i w_i |Fobs|_i2
Ref: Hamilton, W. C. (1965). Acta Cryst. 18, 502-510.
