Extracts the pointwise log-likelihood matrix or array from a model.
This is useful as an input for functions in the loo package.
If called on a ubmsFit object, the log-likelihood matrix or array
is calculated using the posterior distributions of the parameters; the
log-likelihood values are not actually saved inside the model object.
If called on a stanfit object, loo::extract_log_lik is used.
In this case, the log-likelihood must be saved as one of the output
parameters in Stan.
extract_log_lik(object, parameter_name = "log_lik", merge_chains = TRUE)A ubmsFit or stanfit object
The name of the log-likelihood parameter in the
Stan output; ignored when object is a ubmsFit
If TRUE (the default), all Markov chains are
merged together (i.e., stacked) and a matrix is returned. If ‘FALSE’
they are kept separate and an array is returned.
A matrix (samples x sites) or array (samples x chains x sites)