Item _refine_analyze.RG_free

Description

              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 for the free R set of
               reflections that were excluded 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 amplitude 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_i w_i(|Fobs|_i - G|Fcalc|_i)^2
               Rg = Sqrt( ----------------------------------- )
                                  sum_i w_i |Fobs|_i^2

               Ref: Hamilton, W. C. (1965). Acta Cryst. 18, 502-510.

Category

Mandatory Code

Data Type Code

Enumeration Range

Alias Names