Get information on all parameters (and parameter classes) for which priors may be specified including default priors.
get_prior(formula, data, family = gaussian(), autocor = NULL,
sparse = NULL, internal = FALSE, ...)An object of class formula,
brmsformula, or mvbrmsformula (or one that can
be coerced to that classes): A symbolic description of the model to be
fitted. The details of model specification are explained in
brmsformula.
An object of class data.frame (or one that can be coerced
to that class) containing data of all variables used in the model.
A description of the response distribution and link function to
be used in the model. This can be a family function, a call to a family
function or a character string naming the family. Every family function has
a link argument allowing to specify the link function to be applied
on the response variable. If not specified, default links are used. For
details of supported families see brmsfamily. By default, a
linear gaussian model is applied. In multivariate models,
family might also be a list of families.
An optional cor_brms object describing the
correlation structure within the response variable (i.e., the
'autocorrelation'). See the documentation of cor_brms for a
description of the available correlation structures. Defaults to
NULL, corresponding to no correlations. In multivariate models,
autocor might also be a list of autocorrelation structures.
(Deprecated) Logical; indicates whether the population-level
design matrices should be treated as sparse (defaults to FALSE). For
design matrices with many zeros, this can considerably reduce required
memory. Sampling speed is currently not improved or even slightly
decreased. It is now recommended to use the sparse argument of
brmsformula and related functions.
A flag indicating if the names of additional internal parameters should be displayed. Setting priors on these parameters is not recommended
Currently ignored.
A data.frame with columns prior, class, coef,
and group and several rows, each providing information on a
parameter (or parameter class) on which priors can be specified. The prior
column is empty except for internal default priors.
# NOT RUN {
## get all parameters and parameters classes to define priors on
(prior <- get_prior(count ~ zAge + zBase * Trt + (1|patient) + (1|obs),
data = epilepsy, family = poisson()))
## define a prior on all population-level effects a once
prior$prior[1] <- "normal(0,10)"
## define a specific prior on the population-level effect of Trt
prior$prior[5] <- "student_t(10, 0, 5)"
## verify that the priors indeed found their way into Stan's model code
make_stancode(count ~ zAge + zBase * Trt + (1|patient) + (1|obs),
data = epilepsy, family = poisson(),
prior = prior)
# }
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