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.
Usage
paramprecbase(ns, M, N, inverse = FALSE)
Arguments
ns
neighbourhood size
M
number of x cells
N
number of y cells
inverse
whether or not to compute the base matrix
of the inverse precision matrix (ie the covariance
matrix). default is FALSE
Value
a functioin that returns the base matrix of the precision
matrix