主成分分析，一种掌握事物主要矛盾的统计分析方法，它可以从多元事物中解析出主要影响因素，揭示事物的本质，简化复杂的问题，主要用于数据降维-PCA，a kind of statistical analysis method which master the main self-contradict of things, it can resolve the main factors from multiple things　reveal the nature of things, simplify the complex problems,and it mainly used for data dimension reduction.