Basis expansions for smooths — basis • gratia

Creates a basis expansion from a definition of a smoother using the syntax of mgcv's smooths via mgcv::s()., mgcv::te(), mgcv::ti(), and mgcv::t2(), or from a fitted GAM(M).

Usage

basis(object, ...)

# S3 method for class 'gam'
basis(
  object,
  select = NULL,
  term = deprecated(),
  data = NULL,
  n = 100,
  n_2d = 50,
  n_3d = 16,
  n_4d = 4,
  partial_match = FALSE,
  ...
)

# S3 method for class 'scam'
basis(
  object,
  select = NULL,
  term = deprecated(),
  data = NULL,
  n = 100,
  n_2d = 50,
  n_3d = 16,
  n_4d = 4,
  partial_match = FALSE,
  ...
)

# S3 method for class 'gamm'
basis(
  object,
  select = NULL,
  term = deprecated(),
  data = NULL,
  n = 100,
  n_2d = 50,
  n_3d = 16,
  n_4d = 4,
  partial_match = FALSE,
  ...
)

# S3 method for class 'list'
basis(
  object,
  select = NULL,
  term = deprecated(),
  data = NULL,
  n = 100,
  n_2d = 50,
  n_3d = 16,
  n_4d = 4,
  partial_match = FALSE,
  ...
)

# Default S3 method
basis(
  object,
  data,
  knots = NULL,
  constraints = FALSE,
  at = NULL,
  diagonalize = FALSE,
  ...
)

Arguments

object: a smooth specification, the result of a call to one of mgcv::s()., mgcv::te(), mgcv::ti(), or mgcv::t2(), or a fitted GAM(M) model.
...: other arguments passed to mgcv::smoothCon().
select: character; select smooths in a fitted model
term: This argument has been renamed select
data: a data frame containing the variables used in smooth.
n: numeric; the number of points over the range of the covariate at which to evaluate the smooth.
n_2d: numeric; the number of new observations for each dimension of a bivariate smooth. Not currently used; n is used for both dimensions.
n_3d: numeric; the number of new observations to generate for the third dimension of a 3D smooth.
n_4d: numeric; the number of new observations to generate for the dimensions higher than 2 (!) of a kD smooth (k >= 4). For example, if the smooth is a 4D smooth, each of dimensions 3 and 4 will get n_4d new observations.
partial_match: logical; in the case of character select, should select match partially against smooths? If partial_match = TRUE, select must only be a single string, a character vector of length 1.
knots: a list or data frame with named components containing knots locations. Names must match the covariates for which the basis is required. See mgcv::smoothCon().
constraints: logical; should identifiability constraints be applied to the smooth basis. See argument absorb.cons in mgcv::smoothCon().
at: a data frame containing values of the smooth covariate(s) at which the basis should be evaluated.
diagonalize: logical; if TRUE, reparameterises the smooth such that the associated penalty is an identity matrix. This has the effect of turning the last diagonal elements of the penalty to zero, which highlights the penalty null space.

Value

A tibble.

Author

Gavin L. Simpson

Examples

load_mgcv()
df <- data_sim("eg4", n = 400, seed = 42)

bf <- basis(s(x0), data = df)
bf <- basis(s(x2, by = fac, bs = "bs"), data = df, constraints = TRUE)