spg.py 文件源码

def unique_sites(self, scaled_positions, symprec=1e-3, output_mask=False,
                     map_to_unitcell=True):
        """Returns a subset of *scaled_positions* containing only the
        symmetry-unique positions.  If *output_mask* is True, a boolean
        array masking the subset is also returned.

        If *map_to_unitcell* is true, all sites are first mapped into
        the unit cell making e.g. [0, 0, 0] and [1, 0, 0] equivalent.

        Example:

        >>> from ase.lattice.spacegroup import Spacegroup
        >>> sg = Spacegroup(225)  # fcc
        >>> sg.unique_sites([[0.0, 0.0, 0.0], 
        ...                  [0.5, 0.5, 0.0], 
        ...                  [1.0, 0.0, 0.0], 
        ...                  [0.5, 0.0, 0.0]])
        array([[ 0. ,  0. ,  0. ],
               [ 0.5,  0. ,  0. ]])
        """
        scaled = np.array(scaled_positions, ndmin=2)
        symnorm = self.symmetry_normalised_sites(scaled, map_to_unitcell)
        perm = np.lexsort(symnorm.T)
        iperm = perm.argsort()
        xmask = np.abs(np.diff(symnorm[perm], axis=0)).max(axis=1) > symprec
        mask = np.concatenate(([True], xmask))
        imask = mask[iperm]
        if output_mask:
            return scaled[imask], imask
        else:
            return scaled[imask]