f{B})_j (f(\mathbf{AB}^{(i)})_j - f(\mathbf{A})_j)

.. math::

    S_{T_i} = \frac{1}{N} \sum_{j=1}^N
    (f(\mathbf{A})_j - f(\mathbf{AB}^{(i)})_j)^2

Parameters
----------
f_A, f_B : array_like (s, n)
    Function values at A and B, respectively
f_AB : array_like (d, s, n)
    Function values at each of the AB pages

Returns
-------
s, st : array_like (s, d)
    First order and total order Sobol' indices.

References
----------
.. [1] Saltelli, A., P. Annoni, I. Azzini, F. Campolongo, M. Ratto, and
   S. Tarantola. "Variance based sensitivity analysis of model
   output. Design and estimator for the total sensitivity index."
   Computer Physics Communications, 181(2):259-270,
   :doi:`10.1016/j.cpc.2009.09.018`, 2010.
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