Precision matrix for Whittle-Matérn fields

Computes the precision matrix for all vertices for a Whittle-Matérn field.

Usage

spde_precision(kappa, tau, alpha, graph, BC = 1, build = TRUE)

Arguments

kappa

Range parameter.

tau

Precision parameter.

alpha

Smoothness parameter (1 or 2).

graph

A metric_graph object.

BC

Set boundary conditions for degree=1 vertices. BC =0 gives Neumann boundary conditions and BC=1 gives stationary boundary conditions.

build

If TRUE, the precision matrix is returned. Otherwise a list list(i,j,x, nv) is returned.

Value

Precision matrix or list.