Fisher判别适合于两类的判别分析。本文采用的鸢尾花数据库中鸢尾花类别有三类，所以先采用Fisher判别对数据进行二分类判别分析，然后采用一对一进行多分类。(Fisher discriminant analysis is suitable for two kinds of discriminant analysis. There are three categories of iris in the iris database in this paper, so the Fisher discriminant analysis is used to classify the data into two categories. Then, one by one is used to classify the data)