This module handles the space group symmetry operations.
The subroutines in this module handle the space group symmetries and their effect on wave functions and matrix elements. They also allow the identification of an irreducible set of k-vectors in the 1BZ, forming the IBZ.
It is advantageous to perform symmetry operations in crystal coordinates; indeed, in these coordinates, the zone is simply a cube and MP meshes are nice and regular. However, the crystal coordinate system introduces minor complications in the application of point group symmetry. A full description is given in algorithms.pdf.