dot-Q function

Helper function to generate precision matrix Q for simulation

This creates the precision matrix from a mesh created by R-INLA with a specified range. This is currently set up to support the standard spde approach of precision matrices and the barrier model version. Similar in purpose to .sp_covar.

.Q(
  mesh,
  barrier.triangles,
  range = 50,
  range_fraction = 0.2,
  sigma_u = 1,
  model = "spde"
)

Arguments

• mesh: The mesh created by R-INLA representing spatial area
• barrier.triangles: the list of triangles of the mesh in the barrier, only used for barrier model
• range: decorrelation range
• range_fraction: the fraction that sets the range over the "land" parts of the barrier model. Only used with the barrier model
• sigma_u: the overall variance of the spatial process
• model: 'spde' for the SPDE approach, 'barrier' for barrier approach

Returns

Q a sparse precision matrix of type dgTMatrix