A function to used in entering elements into the precision matrix of an SPDE model. Not intended for general use.
SPDEprec(a, ord)a function used for creating the precision matrix
parameter a, see Lindgren et al 2011.
the order of the SPDE model, see Lindgren et al 2011.
Benjamin M. Taylor and Barry S. Rowlingson (2017). spatsurv: An R Package for Bayesian Inference with Spatial Survival Models. Journal of Statistical Software, 77(4), 1-32, doi:10.18637/jss.v077.i04.
Finn Lindgren, Havard Rue, Johan Lindstrom. An explicit link between Gaussian fields and Gaussian Markov random fields: the stochastic partial differential equation approach. Journal of the Royal Statistical Society: Series B 73(4)