The Lolimot model (LOcal LInear MOdel Tree) is a model from the neural network
familly. It is able to learn every kind of non-linear relationship.
Compared to a classical neural network, the learning phase of a LOLIMOT model is
quite fast and deterministic.
Once a model is learnt, you have an easy access to analytical derivatives of
your model through a call to the function estim_der_lolimot.