hess: Hessian for the loglikelihood used by ui.probit
Description
This function derives the hessian in order for ui.probit
to run faster.
Usage
hess(par, rho, X.z = X.z, X.y = X.y, y = y, z = z)
Arguments
X.z
Covariate matrix for missingness.
X.y
Covariate matrix for outcome.