def ndredgeswir(b6, b12):
    """
    Normalized Difference Red-edge and SWIR2 (Radoux et al., 2016).

    .. math:: NDREDGESWIR = (b6 - b12)/(b6 + b12)

    :param b6: Red-edge 2.
    :type b6: numpy.ndarray or float
    :param b12: SWIR 2.
    :type b12: numpy.ndarray or float

    :returns NDREDGESWIR: Index value

    .. Tip::

       Radoux, J., Chomé, G., Jacques, D. C., Waldner, F., Bellemans, \
       N., Matton, N., ... Defourny, P. 2016. Sentinel-2’s potential for \
       sub-pixel landscape feature detection. Remote Sensing 8(6), 488. \
       doi:10.3390/rs8060488.
    """

    NDREDGESWIR = (b6 - b12)/(b6 + b12)
    return NDREDGESWIR