def _fit_IC_table(res, ictable):
    """
    Determines cartesian coordinates from an internal coordinate table stored in
    CHARMM residue topology files

    Parameters
    ----------
    res : ResidueTemplate
        The residue template for which coordinates are being determined
    ictable : list[tuple(atoms, measurements)]
        The internal coordinate table

    Notes
    -----
    This method assigns an xx, xy, and xz attribute to ``res``. For the time
    being, this is just a placeholder, as its functionality has not yet been
    implemented (CHARMM does not use a 'traditional' Z-matrix, and I don't know
    of any existing code that will compute the proper cartesian coordinates from
    the form used by CHARMM)
    """
    for atom in res:
        atom.xx = atom.xy = atom.xz = 0.0
