Notes

¹Here, the triple hkl is represented as a column vector; if it is treated as a row vector (as it is in some software packages), the twin matrices discussed in this paper should be transposed.

²Holo and mero are Greek stems meaning whole and part, respectively. This `French School' nomenclature was originally devised to describe crystal morphology and is used here because it is currently popular in the literature. Different nomenclature is also encountered; see, for example, Giacovazzo (1992) or van der Sluis (1989).

³This program is available free of charge to academic users from http://www.bk.psu.edu/faculty/litvin/Download.html or via the CCP14 web site (http://www.ccp14.ac.uk ).