Principal Component Analysis. Very important for pattern recognition(ie. optical character recognition) A great fundamental file for the beginner. Even those who doesn t know what is variance can start learning about OCR basics from this pdf.-Princip

列主元高斯消元法，用C++写的，是PDF文件，但是代码内容是文本形式，可以复制-Out PCA Gaussian elimination with C++ written a PDF file, but the code text form can be copied