The lattice constant, or lattice parameter, refers to the physical dimension of unit cellsin a crystal lattice. Lattices in three dimensions generally have three lattice constants, referred to as a, b, and c. However, in the special case of cubic crystal structures, all of the constants are equal and are referred to as a.
includes ready-made lattice ﬁles for the common lattice types (e.g. bcc, fcc, hcp). It also includes an utility that automatically constructs multiple lattice geometry input ﬁles for common lattices. For instance, makelat Al,Ti fcc,bcc,hcp creates 3 subdirectories containing the appropriate input ﬁles for each speciﬁed lattice.