The optical resolution of the data set, d(opt), is the
expected minimum distance between two resolved peaks in
an electron-density map.
d(opt) = {2[sigma(Patt)2 + sigma(sph)2]}1/2
sigma(Patt) = standard deviation of the Gaussian function
fitted to the Patterson origin peak
sigma(sph) = standard deviation of the Gaussian function
fitted to the origin peak of the spherical
interference function, representing the Fourier
transform of a sphere with radius 1/dmin
dmin = nominal resolution (_reflns.d_resolution_high)
Ref: Vaguine, A. A., Richelle, J. & Wodak, S. J. (1999).
Acta Cryst. D55, 191-205.
(see also http://www.ysbl.york.ac.uk/alexei/sfcheck.html)
Weiss, M. S. (2001). J. Appl. Cryst. 34, 130-135.