Estimate Auxiliary Covariate of Full Data Efficient Influence Function
est_Hn(gn_exp)An estimate of the exposure density (a generalized propensity
score) using the output provided by est_g_exp.
A data.table with two columns, containing estimates of the
auxiliary covariate at the natural value of the exposure H(A, W) and at the
shifted value of the exposure H(A + delta, W).
Compute an estimate of the auxiliary covariate of the efficient influence function required to update initial estimates through logistic tilting models for targeted minimum loss estimation.