GM(1,1) Model Implementation and Applications

GM(1,1) Model 1-4: 1) GM(1,1) simulation model implemented as gm1(x) where x is the input sequence. 2) GM(1,1) prediction model implemented as gm2(x,K) where x is the base sequence and K indicates the K-th data point to predict from the first future data. 3) GM(1,1) group simulation model implemented as gm3(x). 4) GM(1,1) group prediction model implemented as gm4(x,K), which performs well on sequences with clear trends.