可以分别介绍MFA，又名边界Fisher分析。对模式识别十分重要的作用，可以帮助新手更好的理解KNN原理，对人脸识别有着很好的演示作用。-Can introduce MFA respectively, also known as boundary Fisher analysis. For pattern recognition is an important role, can help beginners a better understanding of KNN principle, has