Calculate true propensity scores in the simulation study

This function uses equation (2) in Section S.1.1 of the supplementary material to calculate true propensity scores for subjects in the simulated datasets.

pi.true(X, K)

Arguments

X	a covariate matrix of subjects.
K	the number of treatments.

Value

A matrix of true propensity scores of assigning each subject (row) to each treatment (column).