Improvement of GM (1, 1) model

Base on analysis of GM(1,1), two simplified computational methods are given. Their computational efforts are less than that of the traditional GM(1,1) model , so they can get quick modeling. Moreover their precisions are as high as the GM(1,1) model. The conclusion, which the initiative number has no effect on the prediction, is got, and an improved GM (1, 1) model I is given. Using golden section method, an improved GM (1, 1) model II is given.