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
   ! h# A$ n( Y5 T/ J
2. syms a b;6 W& i- f, l! ^+ y  P; \5 K
   
3. c=[a b]';- ?4 _7 B7 {* R6 u4 w0 y4 d* @
   
4. A=[539.658590944408,544.467335019023,543.118901615168,541.395536784412,539.719603563031,538.320685053971,536.799895148485,539.869612431029,534.915223499512,544.533125668254];
   ( M9 n9 x' |. @
5. B=cumsum(A);
   % q/ t  a' U8 |' D! Z  s+ t
6. n=length(A);
   5 P7 I  A8 U7 S% g( k4 Q
7. for m=1:(n-1)
   ' `8 c4 h8 u3 r- H+ [8 N4 g7 e* q
8.     C(m)=(B(m)+B(m+1))/2;- S$ a\" _2 }1 F! p
   
9. end5 X. |: ]# H4 z7 l, q
   
10. D=A;
    - k% j1 z/ k; I; Z1 u. T4 N
11. D(1)=[];
    , d8 x) W. [( K5 d\" s
12. D=D';8 S( y2 N8 Z: p- O$ p$ E# b
    
13. E=[-C;ones(1,n-1)];( ?# `  @* H' x! K, o0 ]
    
14. c=inv(E*E')*E*D;1 P, E6 @4 W1 V$ v5 l8 h
    
15. c=c';2 R$ u3 {% N) I* x* x
    
16. a=c(1);
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17. b=c(2);$ v% c1 n5 ^1 G, f
    
18. F=[];
    ) T; }0 h* M2 m1 l; r/ z8 e
19. F(1)=A(1);
    + [/ z9 O; b\" Q& B  @% \
20. for m=2:(n+10)* t- E5 c$ Q; U; I
    
21.     F(m)=(A(1)-b/a)/exp(a*(m-1))+b/a;
    4 t2 A5 G! k! v$ f4 e# m( }
22. end# N, H' ^+ P- d% i
    
23. G=[];: R* C0 a# m4 ~. q% S) i
    
24. G(1)=A(1);
    ; v% n% ?* k8 ~3 R
25. for m=2:(n+2)
    $ m; v* P. l5 o; i0 i0 _
26.     G(m)=F(m)-F(m-1);
      L3 E# `' J4 s+ v9 C, @  l
27. end, j, u/ p: \2 h2 Q5 t4 N4 N
    
28. t1=1:10;
    % M0 r# r3 K0 }\" H* n' D9 I% M7 z5 w
29. t2=1:12;
    \" L6 b: O* }5 B
30. plot(t1,A,'r',t2,G,'g'); F$ x+ e6 _, Y( L& [
    

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