FIC_reorder_univar      Univariate ordering under FIC approximation,
                        first m chosen by m iter of dense univariate
                        reordering
VeccTMVN                VeccTMVN
Vecc_reorder            Univariate ordering under Vecchia approximation
find_nn_corr            Find ordered nearest neighbors based on a
                        correlation Matrix. Assuming the absolute value
                        of the correlation is monotonically decreasing
                        with distance. Returns an n X (m + 1) matrix
                        similar to 'GpGp::find_ordered_nn'.
get_sp_inv_chol         Get the inverse upper Cholesky factor under the
                        Vecchia approximation
loglk_censor_MVN        Compute censored multivariate normal (MVN)
                        log-probabilities that have spatial covariance
                        matrices using Vecchia approximation
mvrandn                 Simulate censored multivariate normal (MVN) as
                        censored locations using the Vecchia
                        approximation
pmvn                    Compute multivariate normal (MVN) probabilities
                        that have spatial covariance matrices using
                        Vecchia approximation
ptmvrandn               Simulate censored multivariate normal (MVN) as
                        censored locations using the Vecchia
                        approximation
