说明：  matlab 自带svm的测试, 用设置的数据简单测试svmtrain函数和svmclassify函数，并用图明确表示，自测结果正确，适合初学者
(Matlab is equipped with SVM test, and the svmtrain function and svmclassify function are simply tested with the set data, and the figure clearly indicates that the self-test result is correct and suitable for beginners)