bru_get_mapper: Extract mapper information from INLA model component objects

In inlabru: Bayesian Latent Gaussian Modelling using INLA and Extensions

Extract mapper information from INLA model component objects

Description

The component definitions will automatically attempt to extract mapper information from any model object by calling the generic bru_get_mapper. Any class method implementation should return a bru_mapper object suitable for the given latent model.

Usage

bru_get_mapper(model, ...)

## S3 method for class 'inla.spde'
bru_get_mapper(model, ...)

## S3 method for class 'inla.rgeneric'
bru_get_mapper(model, ...)

## S3 method for class 'inla.cgeneric'
bru_get_mapper(model, ...)

bru_get_mapper_safely(model, ...)

## S3 method for class 'inla_model_reparam'
bru_get_mapper(model, ...)

Arguments

model	A model component object
...	Arguments passed on to other methods

Details

Before implementing your own bru_get_mapper method, check if there is already a general method available that handles your model class, such as bru_get_mapper.inla.spde(), bru_get_mapper.inla.rgeneric(), and bru_get_mapper.inla.cgeneric().

Value

A bru_mapper object defined by the model component

Methods (by class)

• bru_get_mapper(inla.spde): Extract an indexed mapper for the model$mesh object contained in the model object, which is assumed to be of a class supporting relevant fmesher methods.

• bru_get_mapper(inla.rgeneric): Returns the mapper given by a pre-computed mapper, or an index mapper mapping the size of the model graph.

  The easiest method to define a mapper for an inla.rgeneric model is to store the mapper in the object. Alternatively, define your model using a subclass and define a ⁠bru_get_mapper.<subclass>⁠ method that should return the corresponding bru_mapper object.

  The order of precedence for the mapper construction when calling bru_get_mapper(model) has the following precedence:

  1. ⁠bru_get_mapper.<subclass>⁠, if model has a subclass, otherwise

  2. model[["mapper"]] if that is NULL, and otherwise

  3. bm_index() using the size of the graph returned by model[["f"]][["n"]]

• bru_get_mapper(inla.cgeneric): Works the same as the method of inla.rgeneric

• bru_get_mapper(inla_model_reparam): Reparameterised inla model mapper, see inla.spde2.pcmatern_B()

Functions

• bru_get_mapper_safely(): Tries to call the bru_get_mapper, and returns NULL if it fails (e.g. due to no available class method). If the call succeeds and returns non-NULL, it checks that the object inherits from the bru_mapper class, and gives an error if it does not.

See Also

bru_mapper for mapper constructor methods, and the individual mappers for specific implementation details.

Other mappers: bm_aggregate(), bm_collect(), bm_const(), bm_expr(), bm_factor(), bm_fm_mesh_1d, bm_fmesher(), bm_harmonics(), bm_index(), bm_linear(), bm_logitaverage(), bm_logsumexp(), bm_marginal(), bm_matrix(), bm_multi(), bm_pipe(), bm_reparam(), bm_repeat(), bm_scale(), bm_shift(), bm_sum(), bm_taylor(), bru_mapper()

Examples

if (bru_safe_inla()) {
  mesh <- fmesher::fm_rcdt_2d_inla(globe = 2)
  spde <- INLA::inla.spde2.pcmatern(mesh,
    prior.range = c(1, 0.5),
    prior.sigma = c(1, 0.5)
  )
  mapper <- bru_get_mapper(spde)
  ibm_n(mapper)
}

inlabru documentation built on July 28, 2026, 9:07 a.m.