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: s6 _: |6 r; W+ w3 c
   
2. syms a b;
   3 G7 c; n% I8 D, X
3. c=[a b]';
   , g4 z- h5 ^5 Y- o
4. A=[539.658590944408,544.467335019023,543.118901615168,541.395536784412,539.719603563031,538.320685053971,536.799895148485,539.869612431029,534.915223499512,544.533125668254];- v6 y, q8 w5 |& A% X
   
5. B=cumsum(A);
   : s6 D2 W' X5 Q
6. n=length(A);8 p( F* g* f( j
   
7. for m=1:(n-1)' H( Z+ X3 M' g& I\" @
   
8.     C(m)=(B(m)+B(m+1))/2;% x* e5 P$ G+ t9 ~; W1 {# V$ f
   
9. end
     U) F, Q) O% L# I7 y* o' P3 e
10. D=A;; T! j- h2 Q% Q$ F5 N$ m
    
11. D(1)=[];
    3 |9 m- I. @0 e. s9 \/ h
12. D=D';% ~  x  l2 ~9 e% n\" [
    
13. E=[-C;ones(1,n-1)];- a/ @4 e$ `2 `  q$ _
    
14. c=inv(E*E')*E*D;( a% T- I- A9 V7 p
    
15. c=c';1 L/ g* G5 u' ?$ |, ^
    
16. a=c(1);
    + s+ y\" \\" \# K
17. b=c(2);
    ! b' V, K( z) N- J: i  Z. h% ^8 ]
18. F=[];- ?) J# G/ \& K4 M; D$ i  g
    
19. F(1)=A(1);+ @& J4 d  `& o/ M% t# ?+ v
    
20. for m=2:(n+10)' c! d7 k5 E# H! r
    
21.     F(m)=(A(1)-b/a)/exp(a*(m-1))+b/a;% x2 K* m& o0 X9 {1 z1 }1 m6 }\" v
    
22. end
    , Y) X. W8 y) E0 p
23. G=[];
    5 I8 V7 g( I9 `5 S  m3 b% v
24. G(1)=A(1);
    8 J7 O( _+ k+ }  u, a
25. for m=2:(n+2)
    3 }4 z1 J3 j1 j
26.     G(m)=F(m)-F(m-1);
    8 ?/ T3 Y; ]$ B8 x0 e) ^8 {- E
27. end
    8 T5 i: S  A\" l/ p% w
28. t1=1:10;! x2 z. |& x5 d, W5 E/ S
    
29. t2=1:12;
    / k\" l. _$ n) W' y2 j5 B% M) N
30. plot(t1,A,'r',t2,G,'g'): [6 S6 x, [9 t  E
    

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