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; u4 a8 |. ^% b4 Y6 m2 X3 U
   
2. syms a b;
   : r3 \4 l9 N- a. z' J( T) k
3. c=[a b]';
   4 E+ p' O1 \# n1 J6 ?  J+ j5 D3 {
4. A=[539.658590944408,544.467335019023,543.118901615168,541.395536784412,539.719603563031,538.320685053971,536.799895148485,539.869612431029,534.915223499512,544.533125668254];7 M$ S3 [; q  q4 t, k
   
5. B=cumsum(A);\" Q' @2 b, s7 X3 c! q- a9 [
   
6. n=length(A);, \  Q+ P+ d) }+ n8 S! d- e
   
7. for m=1:(n-1)
   $ F' H  g# M+ ^0 n. e
8.     C(m)=(B(m)+B(m+1))/2;
   , t) Z/ ]5 a/ Y
9. end
   3 t1 G, D. i! {/ |3 A# v
10. D=A;/ V5 C& Y8 a% p' S% \$ @( L
    
11. D(1)=[];$ }3 ^8 x0 E: v- J* z, n2 k9 L
    
12. D=D';
    . t  `: s4 V. C) F3 n
13. E=[-C;ones(1,n-1)];! L9 U! n9 X( e. g# n
    
14. c=inv(E*E')*E*D;
    . ?7 b7 {. y9 I- C
15. c=c';
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16. a=c(1);, o) j0 R7 d- d  z: \2 {, w
    
17. b=c(2);
    % z* I+ z  P' y( J$ H
18. F=[];
    ( {0 G3 z2 I$ |0 f' \( l+ {
19. F(1)=A(1);
      B2 `) h/ `0 V4 X1 p
20. for m=2:(n+10)9 I! H3 c2 p  W% r' n' `- N6 G; M
    
21.     F(m)=(A(1)-b/a)/exp(a*(m-1))+b/a;
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22. end
    5 f- a& B) ~  v# w. @, z- c% U/ U
23. G=[];
    1 Y) Z% e* U# R- E% B
24. G(1)=A(1);! |  b$ b+ ^2 b, h% n4 m. c
    
25. for m=2:(n+2)/ m. ~% ^8 j' a* z
    
26.     G(m)=F(m)-F(m-1);
    . i- K# O8 u% \7 e( s
27. end
    . B5 j3 {' l- }
28. t1=1:10;
    ; ^  x1 s! M, X0 H& E; O
29. t2=1:12;
    \" c8 Y* G- [  E+ ^
30. plot(t1,A,'r',t2,G,'g')
    & p. s( ~1 G1 a  ^, ?

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