              The real-space residual RSR, as described by Branden and Jones,\
               evaluated over all atoms in the monomer.\
\
                     sum|p~obs~ - p~calc~|\
               RSR = ---------------------\
                     sum|p~obs~ + p~calc~|\
\
               p~obs~  = the density in an "experimental" map\
               p~calc~ = the density in a "calculated" map\
\
               sum is taken over the specified grid points\
\
               The details of how these maps were calculated should be described\
               in _struct_mon_details.RSR. The sums are taken over all map grid\
               points near the relevant atoms. The radius for including grid\
               points in the calculation should also be given in\
               _struct_mon_details.RSR.\
\
               Ref: Branden, C.-I. \& Jones, T. A. (1990). Nature, 343,\
                    687-689.