A function to compute the parametrised base matrix of a precision matrix of a GMRF on an M x N toral grid with neighbourhood size ns. Note that the precision matrix is block circulant. The returned function operates on a parameter vector as in Rue and Held (2005) pp 187.
paramprecbase(ns, M, N, inverse = FALSE)neighbourhood size
number of x cells
number of y cells
whether or not to compute the base matrix of the inverse precision matrix (ie the covariance matrix). default is FALSE
a functioin that returns the base matrix of the precision matrix