Starting points and retraining

flaml/automl/automl.py

@@ -3569,12 +3569,24 @@ def _search_sequential(self):
                     state.best_config,
                     self.data_size_full,
                 )
-
-                if (
-                    self._trained_estimator.params[self._trained_estimator.ITER_HP]
-                    != self.best_config[self._trained_estimator.ITER_HP]
+                if getattr(self._trained_estimator, "params", {}) and getattr(
+                    self._trained_estimator, "ITER_HP", None
                 ):
-                    logger.warning("early stopping happened")
+                    _hp_trained_iter = self._trained_estimator.params.get(
+                        self._trained_estimator.ITER_HP
+                    )
+                    _best_config_iter = self.best_config.get(
+                        self._trained_estimator.ITER_HP
+                    )
+                    if _hp_trained_iter != _best_config_iter:
+                        logger.warning(
+                            "Early stopping happened when retraining a model with the best configuration."
+                            f" The best config's ITER_HP is {_best_config_iter}"
+                            f" and the actual ITER_HP used for retraining the model is {_hp_trained_iter}."
+                            " This early stopping happens because because flaml needs to do its best effort to"
+                            " retrain without violating the time budget when retrain_full is set to 'budget'. "
+                            " If this mismatch is not desired, please set retrain_full to True."
+                        )
 
                 logger.info(
                     "retrain {} for {:.1f}s".format(self._best_estimator, retrain_time)