I was wondering whether there is something like a “parameter prefix table” for brms regression models, which describes which prefixes are used for what kind of parameter types and ideally how the parameter names are built (including brackets etc).
I searched the internet and did not find any exhaustive explanation.
Is there a documentation I missed or a function in the brms package which contains this information?
Thank you!
Manuel
brms package uses this internally: Rename Parameters — rename_pars • brms
note that brackets are just indexing, not part of the name.
I often use tidybayes::get_variables to quickly see what the names are.
Thanks! I know this function.
My actual problem is, that I have a model which has >> 1000 Parameters. So the output of get_variables is a pretty long vector. What I want to know is the logic how this names are built, to extract a specific subset of theses parameters - say all level 1 random effect.
So what I know are
and I want, for all my future models, a logic to build e.g. a regular expression, to extract the parameters I need. I supposed the best way to accomplish this goal is to understand the naming scheme which, I assumed, must be part oft brms, and therefore easy to get.
I believe the naming scheme is implicit in the function that @mitzimorris linked to. The code is available here:
brms/rename_pars.R at master · paul-buerkner/brms · GitHub, you may be able to read through it and determine what pattern you are looking for
the columns will be output in the order in which the variables are declared in the Stan program generated by BRMS - so if you have the generated Stan program, the ordering is described here: 19 Stan CSV File Format | CmdStan User’s Guide
brms::ranef isn’t a general solution to your question, but it might be sufficient for your use case?