Dr. K. D. Cowtan, Dr. P. Main, University of York

Various algorithms are described, developed for the `dm' density modification package, which have not been described elsewhere. Methods are described for the following problems: Determination of the absolute scale and overall temperature factor of a data set, by a method which is less dependent on data resolution than Wilson statistics; an efficient interpolation algorithm for averaging and its application to refinement of averaging operators; a method for the automatic determination of averaging masks.