说明：  计算测地距离，测地距离是众多距离的一种，在高维流行数据分布空间上，欧式距离不再适用，这时就可用到欧氏距离
(Computing geodesic distance, geodesic distance is a large distance, popular in high-dimensional data distribution space, the Euclidean distance is no longer applicable, then you can use the Euclidean distance)