a value (picked from the `alphas` parameter list) for each target separately (for multi-output settings: multiple prediction targets). When set to `True`, after fitting, the `alpha_` attribute will contain a value for each target. When set to `False`, a single alpha is used for all targets. .. versionadded:: 0.24 store_cv_values : bool Flag indicating if the cross-validation values corresponding to each alpha should be stored in the ``cv_values_`` attribute (see below). This flag is only compatible with ``cv=None`` (i.e. using Leave-One-Out Cross-Validation). .. deprecated:: 1.5 `store_cv_values` is deprecated in version 1.5 in favor of `store_cv_results` and will be removed in version 1.7. Attributes ---------- cv_results_ : ndarray of shape (n_samples, n_alphas) or shape (n_samples, n_targets, n_alphas), optional Cross-validation values for each alpha (only available if ``store_cv_results=True`` and ``cv=None``). After ``fit()`` has been called, this attribute will contain the mean squared errors if `scoring is None` otherwise it will contain standardized per point prediction values. .. versionchanged:: 1.5 `cv_values_` changed to `cv_results_`. coef_ : ndarray of shape (n_features) or (n_targets, n_features) Weight vector(s). intercept_ : float or ndarray of shape (n_targets,) Independent term in decision function. Set to 0.0 if ``fit_intercept = False``. alpha_ : float or ndarray of shape (n_targets,) Estimated regularization parameter, or, if ``alpha_per_target=True``, the estimated regularization parameter for each target. best_score_ : float or ndarray of shape (n_targets,) Score of base estimator with best alpha, or, if ``alpha_per_target=True``, a score for each target. .. versionadded:: 0.23 n_features_in_ : int Number of features seen during :term:`fit`. .. versionadded:: 0.24 feature_names_in_ : ndarray of shape (`n_features_in_`,) Names of features seen during :term:`fit`. Defined only when `X` has feature names that are all strings. .. versionadded:: 1.0 See Also -------- Ridge : Ridge regression. RidgeClassifier : Classifier based on ridge regression on {-1, 1} labels. RidgeClassifierCV : Ridge classifier with built-in cross validation. Examples -------- >>> from sklearn.datasets import load_diabetes >>> from sklearn.linear_model import RidgeCV >>> X, y = load_diabetes(return_X_y=True) >>> clf = RidgeCV(alphas=[1e-3, 1e-2, 1e-1, 1]).fit(X, y) >>> clf.score(X, y) 0.5166... Trì