To solve the great god a question, in a approximate mathematical model was established by the BP neural network, not out of the optimal value, but to find the target range is greater than a certain value of the independent variables, for example, such as the mountain is 8000 meters high, but I want to get peaks over 7000 meters above the range of the independent variables, and as the independent variable and objective function is non-linear, and the relation between the two also are hard to come by, want to ask everybody a great god there are other ways to solve this problem?