| GM(1,1)灰色模型的程序实现function GM1=fungry1(x0) %输入原始数据x0( P5 u9 O% o7 B% s- l+ _ T=input('T=');%从键盘输入从最后一个历史数据算起的第T时点 x1=zeros(1,length(x0));B=zeros(length(x0)-1,2); yn=zeros(length(x0)-1,1);Hatx0=zeros(1,length(x0)+T);' e: a1 k' h" h0 d2 \ Hatx00=zeros(1,length(x0));Hatx1=zeros(1,length(x0)+T); epsilon=zeros(length(x0),1);omega=zeros(length(x0),1);7 e# o$ t/ o4 M for i=1:length(x0) for j=1:i: q4 P1 w$ \ k x1(i)=x1(i)+x0(j); end end" n; i2 J. H. B# s! e& i) T for i=1:length(x0)-14 |8 P. k2 ~& Q* I, Z B(i,1)=(-1/2)*(x1(i)+x1(i+1)); B(i,2)=1;! ~$ J1 n- u( K1 V) P6 ]& m yn(i)=x0(i+1); end' _" V! q' ?7 i/ `- c& [1 b, L' p% A HatA=(inv(B'*B))*B'*yn % GM(1,1)模型参数估计 for k=1:length(x0)+T Hatx1(k)=(x0(1)-HatA(2)/HatA(1))*exp(-HatA(1)*(k-1))+HatA(2)/HatA(1); end+ k. W% P" V1 m$ D+ P: p' f Hatx0(1)=Hatx1(1);" u( E. S; Q& i7 }$ z! h 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 end& E& T7 x* i, F9 w! t6 p for i=1:length(x0) %开始模型检验* W- M) X) f6 Y: \* N- \ Z epsilon(i)=x0(i)-Hatx0(i); omega(i)=(epsilon(i)/x0(i))*100;% D2 }$ X' @; U* A end" B/ J3 h7 E3 ^! Z$ L % x0;Hatx0;epsilon;omega; %必要时去掉%得到各种数据 c=std(epsilon)/std(x0);p=0;7 p: S+ f% d* T& S6 w* W# Z for i=1:length(x0)8 ?: n' t! J8 \1 R3 r if abs(epsilon(i)-mean(epsilon))<0.6745*std(x0)6 v$ c7 Z+ k3 r3 X1 G q0 J! M; f) ? p=p+1; end4 H" t/ E/ H8 z2 f% b end8 { c& w- g4 B9 u/ d2 P; V0 p p=p/length(x0)) A& Z; R% S4 P) z! ? if p>0.95 & c<0.35) q; s3 r, ]/ T& | i disp('The model is good,and the forecast is:'),' [! x' j: b# {- e- @: ] disp(Hatx0(length(x0)+T)) elseif p>0.85 & c<0.5 disp('The model is eligibility,and the forecast is:'),; T* i, W, h6 w4 B7 G disp(Hatx0(length(x0)+T)): J C$ B' S4 g! M4 f elseif p>0.7 & c>0.65 disp('The model is not good,and the forecast is:'),* {" V7 q @; i0 { 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) Hatx00(i)=Hatx0(i); end; O( I% W0 c. A8 y0 E" w( N9 e% e6 }' i z=1:length(x0);" i* J+ i- P& C, b/ k( ` T 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')3 U5 R9 G7 K( g) Z& J 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; w! x* w d8 M1 t, b 0.07925621# g: B% E! y7 o7 u' F+ i0 j 0.052318818 0.041252502 0.021800479 0.053132975 0.089908836 0.109153219 0.079331832& r+ ~/ f( O+ j% w' C 0.342192598 0.099718142 0.135194823 0.109274037. ?. M! ^2 A2 u 0.081520134 A2 r! }' s V8 Z' z) P0 e 0.067876355 0.064706843! {" Y. I; S* U. {) e 0.055562197 0.050848544" A& u% O8 S/ c3 g0 R ]'; |

| 欢迎光临 数学建模社区-数学中国 (http://www.madio.net/) | Powered by Discuz! X2.5 |