LAPODS: a computer program for refinement of lattice parameters using optimal regression

LAPODS is an upgraded version of the program LAPOD for the refinement of lattice parameters using the method of Cohen [Langford (1971). J. Appl. Cryst. 4, 259-260]. The improved version has a number of advanced features. It can detect the most significant systematic errors automatically by means of a statistical F test; it can also operate in a manual mode with corrections set by the user or input manually. The single-value decomposition (SVD) method is used so that the refinement is now more stable. The general formula to calculate the specimen-transparency error has been incorporated and a transparency correction can now be made when the absorption is intermediate between the limiting cases of `thick' or `thin' samples.