Ymin and YMAN are the minimum and maximum value of the output target variable before normalization of the training set, and Yi is the actual value of the output target variable. Compare the difference between the predicted value of the output target variable and the actual value of the output target variable, test the neural network with the test set data, compare the difference between the expected value and the actual value, and check whether the neural network is successful. The mature network model can be obtained through multiple iterations