Fit a Stan model through the chosen backend

Dispatches a fit to the backend recorded on stan_opts (from stan_options()). The compiled model is resolved by model_name from the calling package: for "rstan", package::stanmodels[[model_name]]; for "cmdstanr", inst/stan/<model_name>.stan under package. The calling package is detected automatically and can be overridden with package.

Usage

fit_model(
  model_name,
  dat_stan,
  init,
  stan_opts,
  drop_pars = NULL,
  package = NULL
)

Arguments

model_name

name of the Stan model; used to look up the compiled model in the calling package's stanmodels (rstan) and to locate the .stan source file under its inst/stan/ (cmdstanr).

dat_stan

the Stan data list.

init

the init list, sized to the chain count.

stan_opts

the validated stan_options() list (carrying a backend element).

drop_pars

character vector of parameter names to exclude from the saved draws, or NULL to keep everything. Honored by rstan; cmdstanr cannot drop parameters and warns if any are requested.

package

name of the host package whose model is being fit. Defaults to the package that called fit_model(), which is correct for the usual case of a host package fitting one of its own models.

Value

the backend's fit object (a stanfit or CmdStanMCMC).

Examples

if (FALSE) { # \dontrun{
# From inside a host package that ships a compiled `coverage` model:
opts <- stan_options(chains = 2, iter = 500, seed = 1)
fit <- fit_model("coverage", dat_stan = data_list, init = init_list,
                 stan_opts = opts)
} # }