new features
- implement the Wakanabe-Akaike Information Criterion (WAIC)
- implement the ||-syntax for random effects allowing for the estimation of random effects standard deviations without the estimation of correlations.
- allow to combine multiple grouping factors within one random effects argument using the interaction symbol ':'
- generalize S3 method 'hypothesis' to be used with all parameter classes not just fixed effects. In addition, one-sided hypothesis testing is now possible.
- introduce new family 'multigaussian' allowing for multivariate normal regression.
- introduce new family 'bernoulli' for dichotomous response variables as a more efficient alternative to families 'binomial' or 'categorical' in this special case.
other changes
- slightly change the internal structure of brms to reflect that rstan is finally on CRAN.
- thoroughly check validity of the response variable before the data is passed to Stan.
- prohibit variable names containing double underscores '__' to avoid naming conflicts.
- allow function calls with several arguments (e.g. poly(x,3)) in the formula argument of function 'brm'.
- always center random effects estimates returned by S3 method 'ranef' around zero.
- prevent the use of customized covariance matrices for grouping factors with multiple random effects for now.
- remove any experimental JAGS code from the package.
bug fixes
- fix a bug in S3 method 'hypothesis' leading to an error when numbers with decimal places were used in the formulation of the hypotheses.
- fix a bug in S3 method 'ranef' that caused an error for grouping factors with only one random effect.
- fix a bug that could cause the fixed intercept to be wrongly estimated in the presence of multiple random intercepts.