[jvm-packages] 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 https://github.com/dmlc/xgboost/blob/67c8c967845c05eb52e13bdee478db4cc37a0c09/demo/guide-python/individual_trees.py#L61 .

[wbo4958]

Cool, looks like it's doable.