灰色模型

zhang6880258

我在matlab中用GM（1,1）模型预测，可是误差太大了。请高手指点~~~~~~~~~~

1. clear
   6 S% Z( y5 r) [; B7 Y% \3 v
2. syms a b;; E& _! H5 U  m, ]\" N$ ~( q3 E
   
3. c=[a b]';$ ?) m9 A/ d: s; t+ Z1 r* }
   
4. A=[539.658590944408,544.467335019023,543.118901615168,541.395536784412,539.719603563031,538.320685053971,536.799895148485,539.869612431029,534.915223499512,544.533125668254];
   % z# W  ?4 O' K' L6 |8 {3 E
5. B=cumsum(A);3 W' c; o# T4 E; s9 Z5 T( s
   
6. n=length(A);
   + Z) j# q6 p9 n' `
7. for m=1:(n-1)' d2 S& v0 S4 m  S& P8 a1 Z
   
8.     C(m)=(B(m)+B(m+1))/2;3 ^! X* [5 k0 W/ `& K
   
9. end
   6 A% y) z) c7 d3 `- O$ J
10. D=A;8 w$ x2 w$ k/ @
    
11. D(1)=[];
    0 r5 l! n, E+ b+ j3 \' _
12. D=D';
    $ J  e. K$ {# T1 F3 R
13. E=[-C;ones(1,n-1)];
    0 [% [. y' V$ R& y
14. c=inv(E*E')*E*D;0 F8 C: g# L( U- y5 m( z
    
15. c=c';
    1 e  M; z7 p\" _: r& t
16. a=c(1);
    + \\" L# G# x/ S3 \9 L, N2 x; l\" e
17. b=c(2);2 D! Z# |( H7 P1 T7 j- P0 P& F
    
18. F=[];
    5 V; h9 }& _, i' D7 {
19. F(1)=A(1);7 ~5 @/ n5 l/ P+ {) ^) W2 u# Z/ A3 I
    
20. for m=2:(n+10)) f9 n% d3 B* I( ?
    
21.     F(m)=(A(1)-b/a)/exp(a*(m-1))+b/a;. b1 _4 f$ x0 Q; q' F
    
22. end8 x' A7 f( @' o9 w0 `; ^/ k
    
23. G=[];
    7 V( R- _* X* u; n% |$ k5 a! A
24. G(1)=A(1);9 L+ f: @9 n- J9 [3 }, ]1 j
    
25. for m=2:(n+2)! `4 y0 ~5 k$ Q& T
    
26.     G(m)=F(m)-F(m-1);
    1 h' L! z% R& Y
27. end! C, V6 c4 Z' X0 o\" [: ^, d
    
28. t1=1:10;
    1 A: R+ r5 K+ }% G
29. t2=1:12;
    \" ~% D7 ]& E, k( B9 W* s
30. plot(t1,A,'r',t2,G,'g')
    & r) `1 x0 [( x0 {- S4 s2 l2 e

复制代码

wssl103050