make_standata  R Documentation 
Data for brms Models
Description
Generate data for brms models to be passed to Stan
Usage
make_standata(
formula,
data,
family = gaussian(),
prior = NULL,
autocor = NULL,
data2 = NULL,
cov_ranef = NULL,
sample_prior = "no",
stanvars = NULL,
threads = getOption("brms.threads", NULL),
knots = NULL,
drop_unused_levels = TRUE,
...
)
Arguments
formula 
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 .

data 
An object of class data.frame (or one that can be coerced
to that class) containing data of all variables used in the model.

family 
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.

prior 
One or more brmsprior objects created by
set_prior or related functions and combined using the
c method or the + operator. See also get_prior
for more help.

autocor 
(Deprecated) 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.
It is now recommend to specify autocorrelation terms directly
within formula . See brmsformula for more details.

data2 
A named list of objects containing data, which
cannot be passed via argument data . Required for some objects
used in autocorrelation structures to specify dependency structures
as well as for withingroup covariance matrices.

cov_ranef 
(Deprecated) A list of matrices that are proportional to the
(within) covariance structure of the grouplevel effects. The names of the
matrices should correspond to columns in data that are used as
grouping factors. All levels of the grouping factor should appear as
rownames of the corresponding matrix. This argument can be used, among
others to model pedigrees and phylogenetic effects.
It is now recommended to specify those matrices in the formula
interface using the gr and related functions. See
vignette("brms_phylogenetics") for more details.

sample_prior 
Indicate if draws from priors should be drawn
additionally to the posterior draws. Options are "no" (the
default), "yes" , and "only" . Among others, these draws can
be used to calculate Bayes factors for point hypotheses via
hypothesis . Please note that improper priors are not sampled,
including the default improper priors used by brm . See
set_prior on how to set (proper) priors. Please also note
that prior draws for the overall intercept are not obtained by default
for technical reasons. See brmsformula how to obtain prior
draws for the intercept. If sample_prior is set to "only" ,
draws are drawn solely from the priors ignoring the likelihood, which
allows among others to generate draws from the prior predictive
distribution. In this case, all parameters must have proper priors.

stanvars 
An optional stanvars object generated by function
stanvar to define additional variables for use in
Stan's program blocks.

threads 
Number of threads to use in withinchain parallelization. For
more control over the threading process, threads may also be a
brmsthreads object created by threading . Withinchain
parallelization is experimental! We recommend its use only if you are
experienced with Stan's reduce_sum function and have a slow running
model that cannot be sped up by any other means. Can be set globally for
the current R session via the "brms.threads" option (see
options ).

knots 
Optional list containing user specified knot values to be used
for basis construction of smoothing terms. See
gamm for more details.

drop_unused_levels 
Should unused factors levels in the data be
dropped? Defaults to TRUE .

... 
Other arguments for internal use.

Value
A named list of objects containing the required data
to fit a brms model with Stan.
Author(s)
PaulChristian Buerkner paul.buerkner@gmail.com
Examples
sdata1 < make_standata(rating ~ treat + period + carry + (1subject),
data = inhaler, family = "cumulative")
str(sdata1)
sdata2 < make_standata(count ~ zAge + zBase * Trt + (1patient),
data = epilepsy, family = "poisson")
str(sdata2)