pca

代码说明：

  pca分类算法，3个参数，一个是样本数据x，另外一个是主成分累积贡献率的一个闸值，作为选定主成分个数的一个重要数据。(pca classification algorithm, three parameters, one is the sample data x, the other is the main component of the cumulative contribution rate of the value of a gate, as the number of selected principal components of an important data.)