This function creates the ICAR precision matrices used in the spatial models
icar.Q(xy, threshold, rho = 1, fun = FALSE)An n x 2 matrix of spatial coordinates
Distance threshold for neighborhood definition
The autoregressive parameter. Defaults to 1, which is the Intrinsic Conditionally AutoRegressive model (ICAR)
If TRUE this function returns a function of rho that generates the precision matrix of a ICAR process
An n x n matrix
Constructs the inverse covariance matrix (aside from scaling) for the ICAR model