Figure 2.

Error distributions for a structure factor in the complex plane. (a) The full structure factor for a translation search arises from the summation of contributions from each asymmetric unit (in this case six), leading to a two-dimensional Gaussian probability distribution. (b) In a rotation search five of the contributions (coloured arrows) can be considered as a random walk from the sixth (F _big), leading to a larger two-dimensional Gaussian (three example random walks are shown).