Core dictionary (coreCIF) version 2.3.1




   The least-squares goodness-of-fit parameter S for all
   reflections included in the refinement after the final cycle
   of refinement. Ideally, account should be taken of parameters
   restrained in the least-squares refinement. See also
   _refine_ls_restrained_S_ definitions.

       {  sum | w | Y(obs) - Y(calc) |^2^ |  }^1/2^
   S = { ----------------------------------- }
       {            Nref - Nparam            }

   Y(obs)  = the observed coefficients
             (see _refine_ls_structure_factor_coef)
   Y(calc) = the calculated coefficients
             (see _refine_ls_structure_factor_coef)
   w       = the least-squares reflection weight
   u       = standard uncertainty

   Nref   = the number of reflections used in the refinement
   Nparam = the number of refined parameters

   and the sum is taken over the specified reflections

The permitted range is 0.0 -> infinity

Type: numb

Category: refine

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