Computes the variance function for a Whittle-Matérn field. Warning is not feasible for large graph due to matrix inversion
spde_variance(
kappa,
tau,
range,
sigma,
alpha,
graph,
BC = 1,
include_vertices = FALSE,
directional = F
)Vector with the variance function evaluate at the mesh locations.
Parameter kappa from the SPDE.
Parameter tau from the SPDE.
Range parameter.
Standard deviation parameter.
Smoothness parameter (1 or 2).
A metric_graph object.
boundary conditions
Should the variance at the vertices locations be included in the returned vector?
bool is the model a directional or not. directional only works for alpha=1
Compute the variance \(\rho(s_i,s_i)\) where \(s_i\) are all locations in the mesh of the graph.