def retr_lattice_vecs(xtalstr,ini0):
    """
    Retrieve the lattice vectors.

    The lattice vectors are extracted from the structure instance.
    They are added to the dictionary passed in. The updated dictionary
    is returned. The lattice vectors are given in Bohr.
    """
    # print(xtalstr.real_lattice)
    ini0["a"] = xtalstr.real_lattice[:,0]
    ini0["b"] = xtalstr.real_lattice[:,1]
    ini0["c"] = xtalstr.real_lattice[:,2]
    return ini0