| GM(1,1)灰色模型的程序实现function GM1=fungry1(x0) %输入原始数据x0) ^: L. m; B* `& @4 o8 S T=input('T=');%从键盘输入从最后一个历史数据算起的第T时点% z: v4 G5 @/ g% R9 u7 K) p x1=zeros(1,length(x0));B=zeros(length(x0)-1,2);3 n2 X% y" F0 {. | yn=zeros(length(x0)-1,1);Hatx0=zeros(1,length(x0)+T); Hatx00=zeros(1,length(x0));Hatx1=zeros(1,length(x0)+T); epsilon=zeros(length(x0),1);omega=zeros(length(x0),1);1 K9 r+ o" }8 ]' n+ s0 l+ Y0 i5 M for i=1:length(x0) for j=1:i! K/ f4 J; o4 S o x1(i)=x1(i)+x0(j); end end for i=1:length(x0)-1 p- \2 j' z: e$ T* ] B(i,1)=(-1/2)*(x1(i)+x1(i+1)); B(i,2)=1;' Q$ L4 {) i! k! S yn(i)=x0(i+1); end* Y, o& t+ } s8 A' y& [ HatA=(inv(B'*B))*B'*yn % GM(1,1)模型参数估计3 V+ e. f: D" `2 c for k=1:length(x0)+T4 k \3 t7 z2 x+ q$ D: I Hatx1(k)=(x0(1)-HatA(2)/HatA(1))*exp(-HatA(1)*(k-1))+HatA(2)/HatA(1);' W1 J* H+ j4 Z+ Y. I end3 c. J$ ]4 W9 t# M$ ?$ ` Hatx0(1)=Hatx1(1); for k=2:length(x0)+T Hatx0(k)=Hatx1(k)-Hatx1(k-1);%累计还原得到历史数据的模拟值1 [: V5 S8 {4 g+ N end$ P5 J, }2 z! W) W" m3 f for i=1:length(x0) %开始模型检验$ o" `3 v; D$ s$ U epsilon(i)=x0(i)-Hatx0(i); omega(i)=(epsilon(i)/x0(i))*100; end % x0;Hatx0;epsilon;omega; %必要时去掉％得到各种数据 c=std(epsilon)/std(x0);p=0; for i=1:length(x0)' T# a/ _5 U. l if abs(epsilon(i)-mean(epsilon))<0.6745*std(x0)7 m% v4 k8 Q& J! Q, w p=p+1; end& R& d0 e8 _7 G8 W$ _6 K end- Z% c; M* F z$ g7 ?& _& v4 d3 ^! n p=p/length(x0) if p>0.95 & c<0.35% r. J2 l. ]& {1 ~9 O$ J disp('The model is good,and the forecast is:'),4 C- e- ^3 ^' ?4 _ disp(Hatx0(length(x0)+T))# ^7 ^' M3 M6 T) J4 D3 z+ d! H- E elseif p>0.85 & c<0.5 disp('The model is eligibility,and the forecast is:'), disp(Hatx0(length(x0)+T)) elseif p>0.7 & c>0.65 disp('The model is not good,and the forecast is:'),2 O" A6 Y( M( O; a& |3 c$ L1 F/ V8 y disp(Hatx0(length(x0)+T))- \5 g6 a6 t( t- g1 m, h& s else p<=0.7 & c>0.65 disp('The model is bad and try again')3 V1 W' {7 h* K7 u8 O. D2 a end for i=1:length(x0)' G3 b; h" g0 W( L* o Hatx00(i)=Hatx0(i);0 f5 `2 C2 n! |! U end6 L8 z9 m) g; R& F z=1:length(x0);2 ^/ W8 c7 M+ A: n! s plot(z,x0,'-',z,Hatx00,':') %将原始数据和模拟值画在一个图上帮助观察 text(2,x0(2),'History data: real line')2 @* C" G# X* m% K) x3 Y text(length(x0)/2,Hatx00(length(x0))/2,'Simulation data:broken line'). w1 H% k- S2 @+ K* u/ W endT=input('T=');%从键盘输入从最后一个历史数据算起的第T时点????是指什么啊，请大哥们，大姐们教一下，我急用，请快，谢谢我的初始值x0=[1.620938526 0.079256217 X5 q8 c9 W: K& {, b. @ 0.052318818 0.041252502% H; W' r2 L* s4 ~5 V! G+ B; N7 W 0.021800479" Q8 D' ~. r* ]4 v3 v7 A 0.053132975 0.089908836 0.1091532196 {& N4 r0 N1 ~2 F/ ]3 |' o i% C2 _ 0.0793318324 {0 @) B# R( t% P9 E; H 0.3421925982 Z! N' j8 J# M, z. N 0.099718142 0.135194823# h6 v. L3 R: U7 y* G 0.109274037 0.08152013 0.067876355 k) Z* R, {+ ]3 i7 s' b0 | 0.064706843 0.055562197 0.050848544, I; M3 O+ h- G ]'; |
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