fm_evaluate {fmesher}

Methods for projecting to/from mesh objects

Description

Calculate evaluation information and/or evaluate a function defined on a mesh or function space.

Usage

fm_evaluate(...)

## Default S3 method:
fm_evaluate(mesh, field, ...)

## S3 method for class 'fm_evaluator'
fm_evaluate(projector, field, ...)

fm_evaluator(...)

## S3 method for class 'fm_mesh_2d'
fm_evaluator(mesh, loc = NULL, lattice = NULL, crs = NULL, ...)

## S3 method for class 'fm_mesh_1d'
fm_evaluator(mesh, loc = NULL, xlim = mesh$interval, dims = 100, ...)

## S3 method for class 'fm_tensor'
fm_evaluator(x, loc, ...)

fm_evaluator_lattice(
  mesh,
  xlim = NULL,
  ylim = NULL,
  dims = c(100, 100),
  projection = NULL,
  crs = NULL,
  ...
)

## S3 method for class 'inla.mesh'
fm_evaluator(mesh, loc = NULL, lattice = NULL, crs = NULL, ...)

## S3 method for class 'inla.mesh.1d'
fm_evaluator(mesh, loc = NULL, xlim = mesh$interval, dims = 100, ...)

Arguments

...

Additional arguments passed on to methods.

mesh

An inla.mesh or inla.mesh.1d object.

field

Basis function weights, one per mesh basis function, describing the function to be evaluated at the projection locations

projector

An fm_evaluator object.

loc

Projection locations. Can be a matrix, SpatialPoints, SpatialPointsDataFrame, sf, sfc, or sfg object.

lattice

An fm_lattice_2d() object.

crs

An optional CRS or inla.CRS object associated with loc and/or lattice.

xlim

X-axis limits for a lattice. For R2 meshes, defaults to covering the domain.

dims

Lattice dimensions.

x

fm_tensor() object

ylim

Y-axis limits for a lattice. For R2 meshes, defaults to covering the domain.

projection

One of c("default", "longlat", "longsinlat", "mollweide").

Value

A vector or matrix of the evaluated function

An fm_evaluator object

Methods (by class)

• fm_evaluate(default): The default method calls proj = fm_evaluator(mesh, ...), followed by fm_evaluate(proj, field).

Functions

• fm_evaluate(): Returns the field function evaluated at the locations determined by an fm_evaluator object. fm_evaluate(mesh, field = field, ...) is a shortcut to fm_evaluate(fm_evaluator(mesh, ...), field = field).

• fm_evaluator(): Returns an fm_evaluator list object with evaluation information. The proj element contains a mapping matrix A and a logical vector ok, that indicates which locations were mappable to the input mesh. For fm_mesh_2d and inla.mesh input, proj also contains a matrix bary and vector t, with the barycentric coordinates within the triangle each input location falls in.

• fm_evaluator(fm_mesh_2d): The ... arguments are passed on to fm_evaluator_lattice() if no loc or lattice is provided.

• fm_evaluator_lattice(): Creates an fm_lattice_2d() object, by default covering the input mesh.

• fm_evaluator(inla.mesh): The ... arguments are passed on to fm_evaluator_lattice() if no loc or lattice is provided.

Author(s)

Finn Lindgren [e-mail]

See Also

fm_mesh_2d(), fm_mesh_1d(), fm_lattice_2d()

Examples

if (TRUE) {
  n <- 20
  loc <- matrix(runif(n * 2), n, 2)
  mesh <- fm_rcdt_2d_inla(loc, refine = list(max.edge = 0.05))
  proj <- fm_evaluator(mesh)
  field <- cos(mesh$loc[, 1] * 2 * pi * 3) * sin(mesh$loc[, 2] * 2 * pi * 7)
  image(proj$x, proj$y, fm_evaluate(proj, field))
}

# if (require("ggplot2") &&
#  require("ggpolypath")) {
#  ggplot() +
#    gg(data = fm_as_sfc(mesh), col = field)
# }