Determination of the space group and unit cell for a periodic solid Original Research Article

We present the code for finding a space group and appropriate crystallography unit cell for a periodic solid. A space group is found in a standard form (as given in the International Tables for Crystallography (1992)). An arbitrary choice of the unit cell is allowed as an input in the sense that there exists the infinity of geometrical choices. In addition, the sets of the symmetrically equivalent atoms and the point group for each set, shift vectors which do not change the representation of the space group, are calculated.