Return the data frame containing the gradients for all parameters.
gradients()A list of lists. See Examples.
# \dontrun{
test <- cmdstanr_example("logistic", method = "diagnose")
# retrieve the gradients
test$gradients()
#> param_idx value model finite_diff error
#> 1 0 1.083910 -6.21416 -6.21416 3.58858e-08
#> 2 1 1.800640 -33.18970 -33.18970 4.38607e-08
#> 3 2 0.683175 -19.70780 -19.70780 1.73640e-08
#> 4 3 1.857330 -9.17992 -9.17992 1.12563e-08
# }