The $return_codes() method returns a vector of return codes
from the CmdStan run(s). A return code of 0 indicates a successful run.
return_codes()An integer vector of return codes with length equal to the number of CmdStan runs (number of chains for MCMC and one otherwise).
# \dontrun{
# example with return codes all zero
fit_mcmc <- cmdstanr_example("schools", method = "sample")
#> Warning: 127 of 4000 (3.0%) transitions ended with a divergence.
#> See https://mc-stan.org/misc/warnings for details.
#> Warning: 2 of 4 chains had an E-BFMI less than 0.3.
#> See https://mc-stan.org/misc/warnings for details.
fit_mcmc$return_codes() # should be all zero
#> [1] 0 0 0 0
# example of non-zero return code (optimization fails for hierarchical model)
fit_opt <- cmdstanr_example("schools", method = "optimize")
#> Chain 1 Optimization terminated with error:
#> Chain 1 Line search failed to achieve a sufficient decrease, no more progress can be made
#> Warning: Fitting finished unexpectedly! Use the $output() method for more information.
fit_opt$return_codes() # should be non-zero
#> [1] 1
# }