Fix.

dmlc · Dec 17, 2020 · ec50033 · ec50033
1 parent 8be2cd8
commit ec50033
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Showing 2 changed files with 4 additions and 2 deletions.
diff --git a/python-package/xgboost/callback.py b/python-package/xgboost/callback.py
@@ -456,6 +456,7 @@ def __init__(self, learning_rates):
 
     def after_iteration(self, model, epoch, evals_log):
         model.set_param('learning_rate', self.learning_rates(epoch))
+        return False
 
 
 # pylint: disable=too-many-instance-attributes
@@ -565,7 +566,7 @@ def after_iteration(self, model: Booster, epoch, evals_log):
     def after_training(self, model: Booster):
         try:
             if self.save_best:
-                model = model[: int(model.attr('best_iteration'))]
+                model = model[: int(model.attr('best_iteration')) + 1]
         except XGBoostError as e:
             raise XGBoostError('`save_best` is not applicable to current booster') from e
         return model
@@ -677,6 +678,7 @@ def after_iteration(self, model, epoch, evals_log):
                 else:
                     model.save_model(path)
         self._epoch += 1
+        return False
 
 
 class LegacyCallbacks:

diff --git a/tests/python/test_callback.py b/tests/python/test_callback.py
@@ -148,7 +148,7 @@ def test_early_stopping_save_best_model(self):
                 eval_metric=tm.eval_error_metric, callbacks=[early_stop])
         booster = cls.get_booster()
         dump = booster.get_dump(dump_format='json')
-        assert len(dump) == booster.best_iteration
+        assert len(dump) == booster.best_iteration + 1
 
         early_stop = xgb.callback.EarlyStopping(rounds=early_stopping_rounds,
                                                 save_best=True)