[feature ] return the best model after early stop

[sonetto19999]

Does xgboost4j-spark support to get the best model after early stop?

It seems it will get the model at that iteration which is best iteration + num_early_stopping_rounds, am i wrong?
how could i get the best model?

[wbo4958]

I guess when predicting, you can specify how many trees to be used. But currently, xgboost4j has not supported specifying the tree limit. I will make a PR for it.

[trivialfis]

Jvm doesn't support model slicing yet. @wbo4958 this might help

xgboost/demo/guide-python/individual_trees.py

Line 61 in 67c8c96

def model_slices() -> None:

.

[wbo4958]

Cool, looks like it's doable.