bm_taylor: Mapper for linear Taylor approximations

In inlabru: Bayesian Latent Gaussian Modelling using INLA and Extensions

Mapper for linear Taylor approximations

Description

Provides a pre-computed affine mapping, internally used to represent and evaluate linearisation information. The state0 information indicates for which state the offset was evaluated; The affine mapper output is defined as effect(state) = offset + jacobian %*% (state - state0)

Usage

bm_taylor(offset = NULL, jacobian = NULL, state0 = NULL, values_mapper = NULL)

bru_mapper_taylor(...)

## S3 method for class 'bm_taylor'
ibm_n(mapper, inla_f = FALSE, multi = FALSE, ...)

## S3 method for class 'bm_taylor'
ibm_n_output(mapper, input, ...)

## S3 method for class 'bm_taylor'
ibm_values(mapper, inla_f = FALSE, multi = FALSE, ...)

## S3 method for class 'bm_taylor'
ibm_jacobian(mapper, ..., multi = FALSE)

## S3 method for class 'bm_taylor'
ibm_eval(mapper, input = NULL, state = NULL, ...)

Arguments

offset	For bm_taylor, an offset vector giving the value of the linearisation at state0. May be NULL, interpreted as an all-zero vector of length determined by a non-null Jacobian.
jacobian	For bm_taylor(), the Jacobian matrix, evaluated at state0, or, a named list of such matrices. May be NULL or an empty list, for a constant mapping.
state0	For bm_taylor, the reference state for the linearisation, or a list of such states matching the jacobian list. NULL is interpreted as 0.
values_mapper	mapper object to be used for ibm_n and ibm_values for inla_f=TRUE (experimental, currently unused)
...	Arguments passed on to other methods
mapper	A mapper S3 object, inheriting from bru_mapper.
inla_f	logical; when TRUE for ibm_n() and ibm_values(), the result must be compatible with the INLA::f(...) and corresponding INLA::inla.stack(...) constructions. For ⁠ibm_{eval,jacobian,linear}⁠, the input interpretation may be different. Implementations do not normally need to do anything different, except for mappers of the type needed for hidden multicomponent models such as "bym2", which can be handled by bm_collect.
multi	logical; If TRUE (or positive), recurse one level into sub-mappers
input	Data input for the mapper.
state	A vector of latent state values for the mapping, of length ibm_n(mapper, inla_f = FALSE)

Methods (by generic)

• ibm_eval(bm_taylor): Evaluates linearised mapper information at the given state. The input argument is ignored, so that the usual argument order ibm_eval(mapper, input, state) syntax can be used, but also ibm_eval(mapper, state = state). For a mapper with a named jacobian list, the state argument must also be a named list. If state is NULL, all-zero is assumed.

See Also

bru_mapper, bru_mapper_generics

Other mappers: bm_aggregate(), bm_collect(), bm_const(), bm_factor(), bm_fmesher(), bm_harmonics(), bm_index(), bm_linear(), bm_logsumexp(), bm_marginal(), bm_matrix(), bm_mesh_B(), bm_multi(), bm_pipe(), bm_repeat(), bm_scale(), bm_shift(), bm_sum(), bru_get_mapper(), bru_mapper(), bru_mapper.fm_mesh_1d(), bru_mapper.fm_mesh_2d(), bru_mapper_generics

Examples

m <- bm_taylor(
  offset = rep(2, 3),
  jacobian = matrix(1:6, 3, 2),
  state0 = c(1, 2)
)
ibm_eval2(m, state = 2:3)

inlabru documentation built on Aug. 9, 2025, 1:08 a.m.