def write_lat_vec(in_name, vectors):
    """
    Write vectors to a file

    Parameters
    ----------
    in_name : str
        Name of the file
    vectors : 3 x 3 numpy array
        Lattice vectors

    """
    out_file = open(in_name, 'w')
    for line in [0, 1, 2]:
        out_file.write('{:15.11f}{:15.11f}{:15.11f}\n'.format(vectors[line]
            [0], vectors[line][1], vectors[line][2]))
    out_file.close()
