首页 if self.sample_weight is not None: estimator.tree_.value *= self.sample_weight[:, np.newaxis]是什么意思

if self.sample_weight is not None: estimator.tree_.value *= self.sample_weight[:, np.newaxis]是什么意思

时间: 2023-06-08 08:03:57 浏览: 87

这是一段 Python 代码，其中的if语句检查sample_weight是否为None。如果不是，就将estimator.tree_.value数组乘以sample_weight数组的转置。这段代码可能是用于进行数据加权的。具体的实现需要看上下文。

if self.sample_weight is not None: estimator.tree_.value *= self.sample_weight[:, np.newaxis]仔细解释

这段代码是在对决策树的节点进行加权处理，sample_weight是一个用于加权的数组，如果这个数组不为None，则会将节点的value（表示节点所属的样本个数的数组）乘以对应的加权值，以达到对样本进行加权处理的目的。其中[:, np.newaxis]是为了将一维数组转化为二维数组。

estimator.tree_.value *= self.sample_weight[:, np.newaxis]是什么意思

这段代码是在将样本权重应用到决策树的节点值上，实现了基于加权样本的决策树算法。其中estimator是决策树模型，tree_.value是存储节点值的数组，self.sample_weight是样本权重向量，np.newaxis是在样本权重向量上增加一个维度，用于实现广义矩阵乘法。

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