Computes the sum of second derivatives of the multivariate
inverse Gaussian likelihood with respect to the data argument
x. The function is vectorized for more efficiency.
mig_loglik_laplacian(x, beta, xi, Omega)an n vector
n by d matrix of quantiles
d vector \(\boldsymbol{\beta}\) defining the half-space through \(\boldsymbol{\beta}^{\top}\boldsymbol{\xi}>0\)
d vector of location parameters \(\boldsymbol{\xi}\), giving the expected value
d by d positive definite scale matrix \(\boldsymbol{\Omega}\)