GQdk() returns a matrix with d + 1 columns. The first
column is the weights and the remaining d columns are the
node coordinates.
GQN is a list of lists, containing the
non-redundant quadrature nodes and weights for integration of a scalar
function of a d-dimensional argument with respect to the density
function of the d-dimensional Gaussian density function.
The outer list is indexed by the dimension, d, in the
range of 1 to 20. The inner list is indexed by k,
the order of the quadrature.