  Generating irreducible site-occupancy configurations by taking advantage of
crystal symmetry is a ubiquitous method for accelerating of disordered
structure prediction, which plays an important role in condensed matter physics
and material science. Here, we present a new algorithm for generating
irreducible site-occupancy configurations, that works for arbitrary parent cell
with any supercell expansion matrix, and for any number of atom types with
arbitrary stoichiometry. The new algorithm identifies the symmetrically
equivalent configurations by searching the space group operations of underlying
lattice and building the equivalent atomic matrix based on it. Importantly, an
integer representation of configurations can greatly accelerate the speed of
elimination of duplicate configurations, resulting into a linear scale of run
time with the number of irreducible configurations that finally found.
Moreover, based on our new algorithm, we write the corresponding code named as
disorder in FORTRAN programming language, and the performance test results show
that the time efficiency of our disorder code is superior to that of other
related codes (supercell, enumlib and SOD).
