費雪的判別分析與線性判別分析 https://ccjou.wordpress.com/2014/03/14/%E8%B2%BB%E9%9B%AA%E7%9A%84%E5%88%A4%E5%88%A5%E5%88%86%E6%9E%90%E8%88%87%E7%B7%9A%E6%80%A7%E5%88%A4%E5%88%A5%E5%88%86%E6%9E%90/
LDA (線性識別分析) http://mirlab.org/jang/books/dcpr/feLda.asp?title=11-3%20LDA%20(%BDu%A9%CA%C3%D1%A7O%A4%C0%AAR)&language=chinese
principal component analysis http://www.real-statistics.com/multivariate-statistics/factor-analysis/principal-component-analysis/