inla.barrier.pcmatern {INLA} | R Documentation

## Functions for defining the Barrier models

### Description

Functions for defining Barrier models as an `⁠inla rgeneric⁠` model

### Usage

    inla.barrier.pcmatern(
      mesh,
      barrier.triangles,
      prior.range,
      prior.sigma,
      range.fraction = 0.2,
      enable.INLAspacetime = TRUE
    )

    inla.barrier.polygon(mesh, barrier.triangles, Omega = NULL)

    inla.barrier.q(fem, ranges, sigma = 1, envir = NULL)

    inla.barrier.fem(mesh, barrier.triangles, Omega = NULL)

### Arguments

`mesh` | The mesh to build the model on, from inla.mesh.2d
`barrier.triangles` | The numerical ids of the triangles that make up the barrier area
`prior.range` | 2 parameters `⁠(range0,Prange)⁠` for the prior spatial range. If `Prange` is `NA`, then `range0` is used as a fixed range value (not tested).
`prior.sigma` | 2 parameters `⁠(sig0,Psig)⁠` for the prior marginal standard deviation sigma. If `Psig` is `NA`, then `sig0` is used as a fixed sigma value (not tested).
`range.fraction` | The length of the spatial range inside the barrier area, as a fraction of the range parameter.
`enable.INLAspacetime` | Use the implentation in the package `INLAspacetime` instead if available (default TRUE) if its available. You may need set this option to `FALSE` if you want to extract properties of the model for other use, like for example `inla.rgeneric.q`.
`Omega` | Advanced option for creating a set of permeable barriers (not documented)
`fem` | represents the Barrier model or the Different Terrains (DT) model, by containing all the needed matrices to solve the SPDE
`ranges`, `sigma` | the hyperparameters that determine Q
`envir` | the environment used for caching (with optimize=TRUE), if any

### Details

This model is described in the ArXiv preprint arXiv:1608.03787. For examples, see https://haakonbakkagit.github.io/btopic128.html

- `inla.barrier.pcmatern` This function creates the model component used in inla(...)

- `inla.barrier.polygon` This function constructs SpatialPolygons for the different subdomains (areas)

- `inla.barrier.q`: This function computes a specific precision matrix

- `inla.barrier.fem` This function computes the Finite Element matrices that are needed to compute the precision matrix Q later

### Value

- `inla.barrier.pcmatern` gives the (rgeneric) model object for fitting the model in INLA

- `inla.barrier.polygon` gives the polygon around the barrier (mainly for plotting)

- `inla.barrier.q` is an internal method producing the Q matrix from a result of inla.barrier.fem,

- `inla.barrier.fem` is an internal method producing the Finite Element matrices.

### Author(s)

Haakon Bakka bakka@r-inla.org

### See Also

inla.spde2.pcmatern

[Package INLA version 26.02.05 Index]