A parsable string giving one of the symmetry operations of the
                space group in algebraic form.  If W is a matrix representation
                of the rotational part of the symmetry operation defined by the
                positions and signs of x, y and z, and w is a column of
                translations defined by the fractions, an equivalent position
                X' is generated from a given position X by the equation:
                          X' = WX + w
                (Note: X is used to represent bold_italics_x in International
                Tables for Crystallography Vol. A, Section 5)
                When a list of symmetry operations is given, it is assumed
                that the list contains all the operations of the space
                group (including the identity operation) as given by the
                representatives of the general position in International
                Tables for Crystallography Vol. A.