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
   $ k# X$ ^( M8 x& z
2. syms a b;
   0 Y5 W8 l% \6 B# J5 f& b
3. c=[a b]';- Q5 P3 @( y3 _! |1 w4 A\" s7 h1 ^
   
4. A=[539.658590944408,544.467335019023,543.118901615168,541.395536784412,539.719603563031,538.320685053971,536.799895148485,539.869612431029,534.915223499512,544.533125668254];
   ' I9 I! D0 F' i, R
5. B=cumsum(A);
   + M0 w% Q; }, r; {
6. n=length(A);. k& q. E& j5 |# z3 ?9 h  W( Q
   
7. for m=1:(n-1)
   * o- ^) a4 S/ p4 r: {6 B$ m
8.     C(m)=(B(m)+B(m+1))/2;, \3 V& \& L, V3 o6 R9 E0 x
   
9. end
   * l1 s  ~3 N# O& S) T
10. D=A;
    2 \1 H& l# ]5 l+ I! q
11. D(1)=[];
    \" s6 |  u$ W+ T! I! s  l
12. D=D';( C' o/ t- U3 c; w, o* S- F
    
13. E=[-C;ones(1,n-1)];# ^) Y; t$ r. a1 m
    
14. c=inv(E*E')*E*D;
    3 a5 Q\" i  u' I% |) c
15. c=c';
    + g( n: R6 T7 [* O1 }/ A- c
16. a=c(1);
    * j8 L# d7 Y\" @' ?+ t\" R9 K6 i
17. b=c(2);* r# m6 d7 `8 ]4 t3 _( W. u
    
18. F=[];# u' A8 Z2 S+ t: g) m3 f' p
    
19. F(1)=A(1);
    1 \+ C- U% i* q\" P8 N+ i
20. for m=2:(n+10)8 R: Y; t5 q& G\" v! p$ J( S
    
21.     F(m)=(A(1)-b/a)/exp(a*(m-1))+b/a;' S% s. @$ j. n: {
    
22. end
    9 o: X+ ?' r$ ?/ U9 [$ D/ T& t4 b
23. G=[];# X5 _\" _0 H+ a5 F5 t0 ]/ i5 E
    
24. G(1)=A(1);4 c) d4 ^2 E4 V4 G8 ], m
    
25. for m=2:(n+2)) f. }$ T& ?3 v) J* s2 D* g
    
26.     G(m)=F(m)-F(m-1);) x  f% P( f5 x- _
    
27. end: R# c& V6 i' B# I+ x
    
28. t1=1:10;
    2 _3 J6 m% i% S\" L4 ^/ x* z4 ?$ P
29. t2=1:12;
    * t; }, m3 g' z* F, z# [  g
30. plot(t1,A,'r',t2,G,'g')& a\" ^' m+ n5 e% `3 \
    

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