def map_indices_child2root(child, child_indices):
    """Map RTDC_Hierarchy event indices to root RTDCBase

    Parameters
    ----------
    child: RTDC_Hierarchy
        RTDCBase hierarchy child
    child_indices: 1d ndarray
        child indices to map

    Returns
    -------
    root_indices: 1d ndarray
        hierarchy root indices
        (not necessarily the indices of `parent`)
    """
    while True:
        indices = map_indices_child2parent(child=child,
                                           child_indices=child_indices)
        if isinstance(child.hparent, RTDC_Hierarchy):
            child = child.hparent
            child_indices = indices
        else:
            break
    return indices
Map RTDC_Hierarchy event indices to root RTDCBase

    Parameters
    ----------
    child: RTDC_Hierarchy
        RTDCBase hierarchy child
    child_indices: 1d ndarray
        child indices to map

    Returns
    -------
    root_indices: 1d ndarray
        hierarchy root indices
        (not necessarily the indices of `parent`)