数据库结构的解析，包括答案。详细，清楚。对初学者很有帮助！-The analytical structure of the database, including the answer. Detailed and clear. Helpful for beginners!

本例用RBF网络拟合未知函数，预先设定一个非线性函数，假定函数解析式不清楚的情况下，随机产生x1，x2和由这两个变量按上式得出的y。-In this case, using RBF network fitting of the unknown function preset a nonlinear function, assume that function under the condition of analytic expression is not clear, randomly gen