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
   . G- L. u: E- K$ @7 L
2. syms a b;
   # X9 N' r\" e: c! Z/ F6 `, P4 s
3. c=[a b]';
   6 c7 Z* ?& `% c4 }4 I3 c3 w
4. A=[539.658590944408,544.467335019023,543.118901615168,541.395536784412,539.719603563031,538.320685053971,536.799895148485,539.869612431029,534.915223499512,544.533125668254];6 R* x2 Z2 h5 s
   
5. B=cumsum(A);& m) ?6 F8 h% K/ D7 T3 K* w. |* D
   
6. n=length(A);
   * t+ Y# [) f3 I+ K0 a) ]$ a
7. for m=1:(n-1)
   / K0 U3 C1 b+ z3 Q
8.     C(m)=(B(m)+B(m+1))/2;3 t- O% A/ ], W5 J
   
9. end
   % r7 g' p& z- f6 F7 q2 e, v
10. D=A;8 j) Z, J1 `, [1 b# X$ r\" p
    
11. D(1)=[];. N1 |) x2 A) S8 A# Q+ s
    
12. D=D';
    : I# t4 D- Z! `' i  \! i% @
13. E=[-C;ones(1,n-1)];
    \" y' a  T0 ], V$ u: |/ U( M% r$ K3 u
14. c=inv(E*E')*E*D;. f4 ?8 I9 Y6 b! x/ l# m
    
15. c=c';
    1 {8 @6 r* R1 [; z' {$ c  @
16. a=c(1);; g$ E( ~2 ~. o
    
17. b=c(2);
    + z& p\" {$ m8 j  b
18. F=[];
    \" N\" B9 L' W# ^) K
19. F(1)=A(1);) `( A! e7 ]' t0 x  B
    
20. for m=2:(n+10)/ N6 o2 m4 w* |$ L
    
21.     F(m)=(A(1)-b/a)/exp(a*(m-1))+b/a;8 k! D( a& T9 A4 A3 Y, m3 K9 L
    
22. end
    ; i3 L5 q; k% j\" S0 {+ X( M/ Y( U
23. G=[];, V9 @( s/ ?2 g' |
    
24. G(1)=A(1);
    . }' G! f; e: K0 m1 K9 }
25. for m=2:(n+2)
    ( z8 N% Q$ |' P. A
26.     G(m)=F(m)-F(m-1);
    6 C1 O% f2 @! L( \0 g6 x; Q
27. end2 O* y/ L- A, ~
    
28. t1=1:10;
    % ^/ L0 F6 V, b/ b& E) R* }) p8 E
29. t2=1:12;. i) Q% K) t: O7 R) J
    
30. plot(t1,A,'r',t2,G,'g')7 ~0 }* B' Z& A9 l( y
    

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