We define a new function log_lik() rather than a stats::logLik() method because (in addition to the conceptual difference) the documentation for logLik() states that the return value will be a single number, whereas log_lik() returns a matrix. See the log_lik.stanreg() method in the rstanarm package for an example of defining a method.

log_lik(object, ...)



The object to use.


Arguments passed to methods. See the methods in the rstanarm package for examples.


log_lik() methods should return a \(S\) by \(N\) matrix, where \(S\) is the size of the posterior sample (the number of draws from the posterior distribution) and \(N\) is the number of data points.

See also

  • Guidelines and recommendations for developers of R packages interfacing with Stan and a demonstration getting a simple package working can be found in the vignettes included with rstantools and at mc-stan.org/rstantools/articles.


# See help("log_lik", package = "rstanarm")