check_failed_fits.RdDetects predictions that came back as NA, which indicates the underlying
MAP Bayesian fit failed, and—when warn = TRUE—emits a warning
summarising how many predictions failed and in which subjects.
check_failed_fits(.res)output object (mipdeval_results) from run_eval(), or a
data.frame with raw results.
invisibly, a data.frame of the rows with failed predictions.