def METHOD_NAME(self, element_id=None, xyz_cid0=None, total=False):
    """
    Gets the centroid for one or more CPYRAM13 elements.
    Parameters
    ----------
    element_id : (nelements, ) int ndarray; default=None -> all
        the elements to consider
    xyz_cid0 : dict[int node_id] : (3, ) float ndarray xyz (default=None -> auto)
        the positions of the GRIDs in CID=0
    total : bool; default=False
        should the centroid be summed
    """
    if element_id is None:
        element_id = self.element_id
    (A1, A2, c1, c2) = self._area_centroid(self, element_ids, xyz_cid0)
    centroid = (c1 * A1 + c2 * A2) / (A1 + A2)
    if total:
        centroid = centroid.mean()
    return centroid