dials objects

[topepo]

You convert mtry to a proportion. You might consider changing:

parsnip::set_model_arg(
  model = "boost_tree",
  eng = "catboost",
  parsnip = "mtry",
  original = "rsm",
  func = list(pkg = "dials", fun = "mtry"),
  has_submodel = FALSE
)

to

parsnip::set_model_arg(
  model = "boost_tree",
  eng = "catboost",
  parsnip = "mtry",
  original = "rsm",
  func = list(pkg = "dials", fun = "mtry_prop"),
  has_submodel = FALSE
)

once I I transfer it over to dials from rules where it currently resides.

There are a lot of parameters to this engine (and for lightGBM). If you make a list of the ones that other might tune, we can add dials parameters to make their optimization easier.

[siegfried]

I just noted that num_leaves is missing, which is important according to LightGBM's docs. Should it be added to dials? Or parsnip?