GM(1,1)灰色模型的程序实现function GM1=fungry1(x0) %输入原始数据x0 T=input('T=');%从键盘输入从最后一个历史数据算起的第T时点0 x* n6 s- V6 H# W5 a6 W3 A x1=zeros(1,length(x0));B=zeros(length(x0)-1,2); yn=zeros(length(x0)-1,1);Hatx0=zeros(1,length(x0)+T); Hatx00=zeros(1,length(x0));Hatx1=zeros(1,length(x0)+T);8 ~3 x! ~8 I3 a- ^: l5 r epsilon=zeros(length(x0),1);omega=zeros(length(x0),1);& `6 i- L: W* g4 n+ [9 n for i=1:length(x0) for j=1:i x1(i)=x1(i)+x0(j); end; A0 U9 e4 i/ t! k4 m( D/ B end3 i3 ~: }2 G3 `1 d6 T1 g7 A( { for i=1:length(x0)-1 ~3 ?5 n; K% t# e1 d- f B(i,1)=(-1/2)*(x1(i)+x1(i+1)); B(i,2)=1;! ]' R5 Q* ]! }* w yn(i)=x0(i+1); end$ i% }2 x5 K& U( v m HatA=(inv(B'*B))*B'*yn % GM(1,1)模型参数估计2 R" }0 a( H: ~; P# Z* B! y for k=1:length(x0)+T3 v" |6 z% I/ Q% l Hatx1(k)=(x0(1)-HatA(2)/HatA(1))*exp(-HatA(1)*(k-1))+HatA(2)/HatA(1);0 c0 b# m" U+ B( V, S end: k5 @$ M( V, {# ] Hatx0(1)=Hatx1(1); for k=2:length(x0)+T1 c/ _) |4 K/ B3 ~ Hatx0(k)=Hatx1(k)-Hatx1(k-1);%累计还原得到历史数据的模拟值 end for i=1:length(x0) %开始模型检验' ?% r0 Q! N9 a5 ^7 r epsilon(i)=x0(i)-Hatx0(i);9 v: \4 Y) J! f; N omega(i)=(epsilon(i)/x0(i))*100;8 c$ e: _. k3 s' H$ p. S end/ K' l& t) ?& s3 [4 p( c, c& V % 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)' M- |- q$ W: ~# j E j: t if abs(epsilon(i)-mean(epsilon))<0.6745*std(x0)( P- Q3 Y# H# O3 |3 N9 D p=p+1;) R9 [9 W) q3 P- I5 k end: X* y9 L) k! p) m1 b+ G) c; A end p=p/length(x0) if p>0.95 & c<0.35, r. M7 P( [4 _. w disp('The model is good,and the forecast is:'),7 l1 `& P/ G. Y* e8 r& h disp(Hatx0(length(x0)+T)) elseif p>0.85 & c<0.5- p P) j/ ]& ^+ g/ X disp('The model is eligibility,and the forecast is:'), disp(Hatx0(length(x0)+T)), y* F5 V4 W* n0 r/ s, J elseif p>0.7 & c>0.65 disp('The model is not good,and the forecast is:'), disp(Hatx0(length(x0)+T)) else p<=0.7 & c>0.65 disp('The model is bad and try again') end for i=1:length(x0)2 H4 x) X- k1 e$ U) D3 E% D1 A Hatx00(i)=Hatx0(i);( e- O& r5 [/ ?/ D- t6 } end z=1:length(x0);- o9 Z& ~+ L3 O0 Z [2 M plot(z,x0,'-',z,Hatx00,':') %将原始数据和模拟值画在一个图上帮助观察5 f0 @! M* Z5 F text(2,x0(2),'History data: real line'); c" o( N- C. P" P3 U5 }* ~5 R. P text(length(x0)/2,Hatx00(length(x0))/2,'Simulation data:broken line') 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 0.07925621 0.052318818- B- B% _ h6 O2 T 0.041252502; T2 }) m3 a, P! a7 w! D 0.021800479 0.053132975 0.089908836 0.109153219 0.079331832- [5 M! I1 Q; w 0.342192598 F3 t- ?. d+ q9 h) K. | 0.099718142 0.1351948238 d) b- S4 n, J/ Y0 Q$ l 0.109274037: V, u5 l3 N7 g: `. w 0.08152013! E$ o- m# M9 k 0.0678763551 M: [# Q. A1 k: r! J- K9 H 0.064706843 0.0555621979 k: R& w. w: J- d4 V( d( l 0.050848544+ T* `8 C2 p" R/ _/ C, v ]'; |
欢迎光临 数学建模社区-数学中国 (http://www.madio.net/) | Powered by Discuz! X2.5 |