Can someone please post what sigmoidnet function, under nonlinear ARX model in the system identification toolbox, is taking as input and how it is taking a time series data?
More precisely, the function of the sigmoidnet is written below,
F(x) = (x-r)*P*L + a_1 f((x-r)*Q*b_1+c_1) + .. ... + a_n f((x-r)*Q*b_n+c_n) + d
where f is the sigmoid function and n is the number of units of the function.
But, in the above formulation, what is x? and how the regressor mean (r) is calculated?