inla.mesh.basis {INLA} | R Documentation

## Basis functions for inla.mesh

### Description

since `⁠23.08.18⁠`. Use `fmesher::fm_raw_basis()` instead.

Calculate basis functions on a 1d or 2d `inla.mesh()`

### Usage

    inla.mesh.basis(
      mesh,
      type = "b.spline",
      n = 3,
      degree = 2,
      knot.placement = "uniform.area",
      rot.inv = TRUE,
      boundary = "free",
      free.clamped = TRUE,
      ...
    )

### Arguments

`mesh` | An `inla.mesh.1d` or `inla.mesh` object.
`type` | `b.spline` (default) for B-spline basis functions, `sph.harm` for spherical harmonics (available only for meshes on the sphere)
`n` | For B-splines, the number of basis functions in each direction (for 1d meshes `n` must be a scalar, and for planar 2d meshes a 2-vector). For spherical harmonics, `n` is the maximal harmonic order.
`degree` | Degree of B-spline polynomials. See `inla.mesh.1d()`.
`knot.placement` | For B-splines on the sphere, controls the latitudinal placements of knots. `"uniform.area"` (default) gives uniform spacing in `sin(latitude)`, `"uniform.latitude"` gives uniform spacing in latitudes.
`rot.inv` | For spherical harmonics on a sphere, `rot.inv=TRUE` gives the rotationally invariant subset of basis functions.
`boundary` | Boundary specification, default is free boundaries. See `inla.mesh.1d()` for more information.
`free.clamped` | If `TRUE` and `boundary` is `"free"`, the boundary basis functions are clamped to 0/1 at the interval boundary by repeating the boundary knots.
`...` | Unused

### Author(s)

Finn Lindgren finn.lindgren@gmail.com

### See Also

`inla.mesh.1d()` `inla.mesh.2d()`

### Examples

    n <- 100
    loc <- matrix(runif(n * 2), n, 2)
    mesh <- inla.mesh.2d(loc, max.edge = 0.05)
    basis <- inla.mesh.basis(mesh, n = c(4, 5))

    proj <- inla.mesh.projector(mesh)
    image(proj$x, proj$y, inla.mesh.project(proj, basis[, 7]))

    if (require(rgl)) {
      plot(mesh, rgl = TRUE, col = basis[, 7], draw.edges = FALSE, draw.vertices = FALSE)
    }

[Package INLA version 26.02.05 Index]