inlabru (version 2.8.0)

fm_int: Multi-domain integration

Description

Construct integration points on tensor product spaces

Usage

fm_int(domain, samplers = NULL, ...)
# S3 method for list
fm_int(domain, samplers = NULL, ...)
# S3 method for numeric
fm_int(domain, samplers = NULL, name = "x", ...)
# S3 method for character
fm_int(domain, samplers = NULL, name = "x", ...)
# S3 method for factor
fm_int(domain, samplers = NULL, name = "x", ...)
# S3 method for SpatRaster
fm_int(domain, samplers = NULL, name = "x", ...)
# S3 method for inla.mesh.lattice
fm_int(domain, samplers = NULL, name = "x", ...)
# S3 method for inla.mesh.1d
fm_int(domain, samplers = NULL, name = "x", int.args = NULL, ...)
# S3 method for inla.mesh
fm_int(
  domain,
  samplers = NULL,
  name = NULL,
  int.args = NULL,
  format = NULL,
  ...
)

Value

A data.frame, tibble, sf, or SpatialPointsDataFrame of 1D and 2D integration points, including a weight column and .block column.

Arguments

domain

Functional space specification; single domain or a named list of domains

samplers

For single domain fm_int methods, an object specifying one or more subsets of the domain, and optional weighting in a weight variable. For fm_int.list, a list of sampling definitions, where data frame elements may contain information for multiple domains, in which case each row represent a separate tensor product integration subspace.

...

Additional arguments passed on to other methods

name

For single-domain methods, the variable name to use for the integration points. Default 'x'

int.args

List of arguments passed to line and integration methods.

• method: "stable" (to aggregate integration weights onto mesh nodes) or "direct" (to construct a within triangle/segment integration scheme without aggregating onto mesh nodes)

• nsub1, nsub2: integers controlling the number of internal integration points before aggregation. Points per triangle: (nsub2+1)^2. Points per knot segment: nsub1

format

character; determines the output format, as either "sf" (default when the sampler is NULL) or "sp". When NULL, determined by the sampler type.

Methods (by class)

• fm_int(list): Multi-domain integration

• fm_int(numeric): Discrete double or integer space integration

• fm_int(character): Discrete character space integration

• fm_int(factor): Discrete factor space integration

• fm_int(SpatRaster): SpatRaster integration. Not yet implemented.

• fm_int(inla.mesh.lattice): inla.mesh.lattice integration. Not yet implemented.

• fm_int(inla.mesh.1d): inla.mesh.1d integration. Supported samplers:

  • NULL for integration over the entire domain;

  • A length 2 vector defining an interval;

  • A 2-column matrix with a single interval in each row;

  • A tibble with a named column containing a matrix, and optionally a weight column.

• fm_int(inla.mesh): inla.mesh integration. Any sampler class with an associated fm_int_inla_mesh() method is supported.

Examples

if (bru_safe_inla() && bru_safe_sp()) {
  # Integration on the interval (2, 3.5) with Simpson's rule
  ips <- fm_int(INLA::inla.mesh.1d(0:4), samplers = cbind(2, 3.5))
  plot(ips)

  # Create integration points for the two intervals [0,3] and [5,10]

  ips <- fm_int(
    INLA::inla.mesh.1d(0:10),
    matrix(c(0, 3, 5, 10), nrow = 2, byrow = TRUE)
  )
  plot(ips)

  # Convert a 1D mesh into integration points
  mesh <- INLA::inla.mesh.1d(seq(0, 10, by = 1))
  ips <- fm_int(mesh, name = "time")
  plot(ips)


  if (require("ggplot2", quietly = TRUE)) {
    data("gorillas", package = "inlabru")
    #' Integrate on a 2D mesh with polygon boundary subset
    ips <- fm_int(gorillas$mesh, gorillas$boundary)
    ggplot() +
      gg(gorillas$mesh) +
      gg(gorillas$boundary) +
      gg(ips, aes(size = weight)) +
      scale_size_area()
  }
}