spg.py 文件源码

def symmetry_normalised_sites(self, scaled_positions, 
                                  map_to_unitcell=True):
        """Returns an array of same size as *scaled_positions*,
        containing the corresponding symmetry-equivalent sites of
        lowest indices.

        If *map_to_unitcell* is true, the returned positions are all
        mapped into the unit cell, i.e. lattice translations are
        included as symmetry operator.

        Example:

        >>> from ase.lattice.spacegroup import Spacegroup
        >>> sg = Spacegroup(225)  # fcc
        >>> sg.symmetry_normalised_sites([[0.0, 0.5, 0.5], [1.0, 1.0, 0.0]])
        array([[ 0.,  0.,  0.],
               [ 0.,  0.,  0.]])
        """
        scaled = np.array(scaled_positions, ndmin=2)
        normalised = np.empty(scaled.shape, np.float)
        rot, trans = self.get_op()
        for i, pos in enumerate(scaled):
            sympos = np.dot(rot, pos) + trans
            if map_to_unitcell:
                # Must be done twice, see the scaled_positions.py test
                sympos %= 1.0
                sympos %= 1.0
            j = np.lexsort(sympos.T)[0]
            normalised[i,:] = sympos[j]
        return normalised