对数据进行聚类，方便进行下一步的计算，如20个数，分为四类，就会根据其数字特性按照最小二乘进行分类，并计算出质心-Clustering of the data to facilitate the next step of the calculation, such as the number 20 is divided into four categories according to their number of properties will be classified according to least squares and calculate the centroid