Diffraction methods for biological macromolecules. Least squares refinement.

Most of the methods mentioned in this chapter were known in the early 1960s. Because of the availability of large, fast computers, however, the most popular technique has been the full-matrix least-squares method. The most significant contributions to crystallographic least-squares calculations which have recently been developed have been for protein or polynucleotide structure refinement. It is clear that these new techniques and those of the early 1960s are more economical than the full-matrix least-squares method even for small-molecule structures.