For each reflection class, the residual factor for all reflections included in the refinement. The reflections also satisfy the resolution limits established by _reflns_class.d_res_high and _reflns_class.d_res_low. This is the conventional R factor. See also the definition of _reflns_class.wR_factor_all. sum | F(obs) - F(calc) | R = ------------------------ sum | F(obs) | F(obs) = the observed structure-factor amplitudes F(calc) = the calculated structure-factor amplitudes and the sum is taken over the reflections of this class.