BUNYIP: in search of errant symmetry

BUNYIP is a computer program for detecting additional symmetry in a crystal structure. It searches for points, lines or planes that form the common loci for midpoints of vectors between atom sites related by non-space-group symmetry. These signal the existence of additional inversion centres, twofold rotation and screw axes or mirror and glide planes. This software is available as part of the Xtal_GX and Xtal3.4 packages, which also provide software for visualization of the new symmetry elements.