This is the second major release of brms
. The main
new feature are generalized multivariate models, which now
support everything already possible in univariate models,
but with multiple response variables. Further, the internal
structure of the package has been improved considerably to be
easier to maintain and extend in the future.
In addition, most deprecated functionality and arguments have
been removed to provide a clean new start for the package.
Models fitted with brms
1.0 or higher should remain
fully compatible with brms
2.0.
new features
- Add support for generalized multivariate models,
where each of the univariate models may have a different
family and autocorrelation structure.
Residual correlations can be estimated for multivariate
gaussian
andstudent
models. All features
supported in univariate models are now also available in
multivariate models. (#3) - Specify different formulas for different
categories incategorical
models. - Add weakly informative default priors for the
parameter classIntercept
to improve convergence
of more complex distributional models. - Optionally display the MC standard error in the
summary
output. (#280) - Add argument
re.form
as an alias of
re_formula
to the methodsposterior_predict
,
posterior_linpred
, andpredictive_error
for consistency with other packages making use of
these methods. (#283)
other changes
- Refactor many parts of the package to make
it more consistent and easier to extend. - Show the link functions of all
distributional parameters in thesummary
output. (#277) - Reduce working memory requirements when
extracting posterior samples for use inpredict
and related methods thanks to Fanyi Zhang. (#224) - Remove deprecated aliases of functions
and arguments from the package. (#278) - No longer support certain prior specifications,
which were previously labeled as deprecated. - Remove the depreacted addition term
disp
from the package. - Remove old versions of methods
fixef
,
ranef
,coef
, andVarCorr
. - No longer support models fitted with
brms
< 1.0,
which used the multivariate'trait'
syntax
orginally deprecated inbrms
1.0. - Make posterior sample extraction in the
summary
method cleaner and less error prone. - No longer fix the seed for random number generation
inbrm
to avoid unexpected behavior in simulation studies.
bug fixes
- Store
stan_funs
inbrmsfit
objects
to allow usingupdate
on models with user-defined
Stan functions thanks to Tom Wallis. (#288) - Fix problems in various post-processing methods
when applied to models with the reserved variable
intercept
in group-level terms thanks to
the GitHub user ASKurz. (#279) - Fix an unexpected error in
predict
and related
methods when settingsample_new_levels = "gaussian"
in models with only one group-level effect.
Thanks to Timothy Mastny. (#286)