Sklearn 在内部克隆估计器,以创建估计器的多个副本。参考 https://github.com/scikit-learn/scikit-learn/blob/7389dba/sklearn/model_selection/_validation.py#L230; using clone
功能。
from sklearn.base import clone
t = MyEstimator('some value')
t1 = clone(t)
t._member, t1._member
#
('some value', None)
clone https://github.com/scikit-learn/scikit-learn/blob/7389dba/sklearn/base.py#L30仅从对象复制构造函数参数值。
解决方案:
使构造函数参数和对象属性保持一致,因此以下划线开头或删除所有下划线!
class MyEstimator(BaseEstimator):
def __init__(self, member):
self.member = member
def fit(self, X, y):
if self.member is None:
raise Exception('member is None.')
def predict(self, X):
return [1]
X = np.array([[1, 1, 1], [2 ,2 , 2],[3,3,3]])
y = np.array([1, 2,3])
score_values = cross_val_score(
MyEstimator('some value'),
X,
y,
cv=3,
scoring='r2',error_score='raise'
)