KPCA用于数据特征的降维，先通过核方法，将样本映射到高维空间，再进行主成分分析过程。(KPCA is used to reduce the dimension of data, first through the kernel method, the sample is mapped to high-dimensional space, and then the principal component analysis process.)

该脚本可以用于降维或者特征选择，名字为主成分分析。(Dimensionality reduction)

主成分分析降维代码，完整版，可以直接放进matlab运行。(Principal component analysis dimension reduction code, complete version, can be directly put into Matlab to run.)