对于二进制分类问题,我想使用MLPClassifier作为AdaBoostClassifier中的基本估计量。但是,这不起作用,因为MLPClassifier未实现sample_weight,这是AdaBoostClassifier所必需的(请参见here)。在此之前,我尝试使用Keras模型和KerasClassifier中的AdaBoostClassifier,但是也不能像here所述那样使用。

用户V1nc3nt提出的way是在TensorFlow中构建自己的MLPclassifier并考虑sample_weight。

用户V1nc3nt共享了他的大部分代码,但是由于我对Tensorflow的经验有限,因此我无法填写缺少的部分。因此,我想知道是否有人找到了用于从MLP构建Adaboost集成的可行解决方案,或者可以帮助我完成V1nc3nt提出的解决方案。

提前非常感谢您!

最佳答案

根据您提供的参考,我修改了MLPClassifier以适应sample_weights

尝试这个!

from sklearn.neural_network import MLPClassifier
from sklearn.datasets import load_iris
from sklearn.ensemble import AdaBoostClassifier

class customMLPClassifer(MLPClassifier):
    def resample_with_replacement(self, X_train, y_train, sample_weight):

        # normalize sample_weights if not already
        sample_weight = sample_weight / sample_weight.sum(dtype=np.float64)

        X_train_resampled = np.zeros((len(X_train), len(X_train[0])), dtype=np.float32)
        y_train_resampled = np.zeros((len(y_train)), dtype=np.int)
        for i in range(len(X_train)):
            # draw a number from 0 to len(X_train)-1
            draw = np.random.choice(np.arange(len(X_train)), p=sample_weight)

            # place the X and y at the drawn number into the resampled X and y
            X_train_resampled[i] = X_train[draw]
            y_train_resampled[i] = y_train[draw]

        return X_train_resampled, y_train_resampled


    def fit(self, X, y, sample_weight=None):
        if sample_weight is not None:
            X, y = self.resample_with_replacement(X, y, sample_weight)

        return self._fit(X, y, incremental=(self.warm_start and
                                            hasattr(self, "classes_")))


X,y = load_iris(return_X_y=True)
adabooster = AdaBoostClassifier(base_estimator=customMLPClassifer())

adabooster.fit(X,y)

关于machine-learning - 在AdaBoostClassifier中使用scikit-learn的MLPClassifier,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/55632010/

10-09 05:38