feat: add ml.metrics.mean_squared_error (#559)

* feat: add ml.metrics.mean_squared_error * fix docs * fix docs

Author: GarrettWu

bigframes/ml/metrics/__init__.py

@@ -18,6 +18,7 @@
  auc,
  confusion_matrix,
  f1_score,
+ mean_squared_error,
  precision_score,
  r2_score,
  recall_score,
@@ -35,5 +36,6 @@
  "confusion_matrix",
  "precision_score",
  "f1_score",
+ "mean_squared_error",
  "pairwise",
 ]

bigframes/ml/metrics/_metrics.py

@@ -335,3 +335,17 @@ def f1_score(
 
 
 f1_score.__doc__ = inspect.getdoc(vendored_metrics_classification.f1_score)
+
+
+def mean_squared_error(
+ y_true: Union[bpd.DataFrame, bpd.Series],
+ y_pred: Union[bpd.DataFrame, bpd.Series],
+) -> float:
+ y_true_series, y_pred_series = utils.convert_to_series(y_true, y_pred)
+
+ return (y_pred_series - y_true_series).pow(2).sum() / len(y_true_series)
+
+
+mean_squared_error.__doc__ = inspect.getdoc(
+ vendored_metrics_regression.mean_squared_error
+)