yzhao062/pyod

knn metric cosine ValueError: Unrecognized metric 'cosine'

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#221 创建于 2020年8月19日

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 (3 评论) (0 反应) (1 负责人)Python (7,762 star) (1,308 fork)batch import
bughelp wanted

描述

clf = KNN(metric="cosine")
clf.fit(train_data)

results in

sklearn/neighbors/_binary_tree.pxi in sklearn.neighbors._ball_tree.BinaryTree.__init__()

sklearn/neighbors/_dist_metrics.pyx in sklearn.neighbors._dist_metrics.DistanceMetric.get_metric()

ValueError: Unrecognized metric 'cosine'

Also brute and kd_tree don't support cosine, meaning that cosine is not supported by any algorithm.

贡献者指南

技术栈
pythonscikit learn
领域
machine learning
议题类型
bug
难度面向新贡献者的预计实现难度，1 表示很小改动，5 表示专家级工作。
3
预计时间有经验贡献者完成调查、实现、测试并准备 pull request 的粗略时间范围。
1-3 hours
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blocked
清晰度议题是否清楚说明期望改动、验收标准和下一步。
clear
前置要求
Pythonscikit learn
新手友好度1-100 的估计分数，表示该议题对首次贡献者的友好程度。
40
研究方向
The issue is that the 'cosine' metric is not recognized by sklearn's BallTree or KDTree. The error trace indicates it stems from DistanceMetric.get metric. To fix, one could add 'cosine' to the list of supported metrics in pyod's KNN implementation, possibly by mapping it to a valid metric or computing cosine distance manually. Relevant files include pyod/models/knn.py or pyod/utils/utility.py.