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function SGrey* d9 L. d% {4 s$ a& R! ]5 E
' ^, J+ c) s3 f3 d/ [X0 = input('请输入原始负荷数据:'); %输入原始数据; X d* p; H: J3 A% T
n = length(X0); %原始n年数据0 \" Z' f( S) L) Q
2 d2 y2 ]2 Q5 F- d%累加生成0 G+ W3 c# H* U8 d( D. i% F2 z' O
X1 = zeros(1,n);5 V! o5 x# ^4 S. {2 X& l# ]
for i = 1:n
& N* m U9 E) G! k6 M% A if i == 1
3 w# r( W% D5 ? r) u X1(1,i) = X0(1,i);+ y) V% b* c+ O4 ?
else
; {2 X7 D% @1 V X1(1,i) = X0(1,i) + X1(1,i-1);+ \ c! H7 j7 G1 e
end) I. G9 C# y9 F
end
6 Z& @0 j( n- t% wX1
5 f( Q6 e: ^9 N- g; j. j' P1 O/ `$ |& O- }% M2 `& J' Y5 a0 M* A! `2 N0 l
%计算数据矩阵B和数据向量Y% z: f8 p8 G% Q. @0 I/ @& l
B = zeros(n-1,2);+ @" C: ^* s) f) l. P
Y = zeros(n-1,1);
: K2 |; U' `- ?for i = 1:n-1
* ^! R4 a- M: Z+ o0 w B(i,1) = -0.5*(X1(1,i) + X1(1,i+1));' X2 z: d& D( t8 F' g
B(i,2) = 1;
1 d3 n/ c: c/ y; b, ~8 ]4 v Y(i,1) = X0(1,i+1);
. A4 M) s, ?% fend
( w) A4 n, v+ o) o3 F8 lB,Y1 i8 `( a9 N# b1 E6 A# V5 L) b
- K! p2 c' v4 c& F6 O% r0 F6 v5 }%计算GM(1,1)微分方程的参数a和u) m9 V* ~" ~1 s1 p2 Z% J' o
A = zeros(2,1); R- n. M! h' @- Q5 D4 J- P
A = inv(B'*B)*B'*Y;- F8 c+ k' l% J( e# ^
a = A(1,1);
7 F& ]8 c* r' p v7 _# Eu = A(2,1);
. x+ D1 p, ?& C: B$ [) G5 La,u
4 {0 k* y( \0 k7 H, ]. Z8 Z1 ^0 ^( L8 z& Y3 M
%建立灰色预测模型
. R5 c7 E6 |9 _XX0(1,1) = X0(1,1);
. D i1 X4 X) I: }/ mfor i = 2:n2 X: e3 c6 G. R0 g
XX0(1,i) = (X0(1,1) - u/a)*(1-exp(a))*exp(-a*(i-1));
$ ^1 \8 `1 r4 \: X0 Wend. A' L4 H3 O; B4 m
XX0
! f0 P/ }' h) W5 w g" h%模型精度的后验差检验1 R$ H, j: H9 n- F, x' j4 e- o9 W
e = 0; %求残差平均值
) {. e+ \6 f1 z; d* u' X S7 mfor i =1:n# v' V: t' D/ C$ `' Z3 a w3 I# U7 O
e = e + (X0(1,i) - XX0(1,i));
. W. L2 x: P$ }! C. i) P3 U: L9 Wend& `2 d* F* l0 {5 }3 F1 y
e = e/n;
% u, `$ v+ O2 Y8 @, H# Ve7 y$ ?, g& h" h
aver = 0; %求历史数据平均值
, V! P% ?8 X6 Rfor i = 1:n5 P1 X$ o9 W& L4 o: t) G( P `/ ]
aver = aver + X0(1,i);
3 C2 s; v, t- gend& J: L t, c9 B S% D
aver = aver / n;: i) z8 t9 }% a7 M& y' B
aver3 t+ z; @, \, L% a- D M/ y
s12 = 0; %求历史数据方差
E) [/ P: ]6 [4 S. W Vfor i = 1:n% s" ~2 z; m9 I# p
s12 = s12 + (X0(1,i)-aver)^2;
5 W7 r; t: X. R3 d% j- _end
M- W# A M* ~7 ts12 = s12 / n;" n7 h; u6 q: p) n, G# t; R4 c9 Y
s12/ P% j1 U; w( ~+ e
s22 = 0; %求残差方差! I* L& U$ Z" H6 q0 A9 R
for i = 1:n
' _' D* \6 O( g6 N% L( _ s22 = s22 + ((X0(1,i) - XX0(1,i)) - e)^2;0 e0 }1 h$ `3 ]
end: g5 ^+ d# A, i/ m# O* x3 \
s22 = s22 / n;. u) I: p) W/ m5 L
s22* o4 m! s7 i |3 S, E
C = s22 / s12; %求后验差比值
( ]4 X: h+ @1 ^C4 f( ]: m7 R" f6 D5 ]* H
cout = 0; %求小误差概率. L% m% t/ X' Q; z
for i = 1:n/ g8 J$ A/ l v6 X4 {
if abs((X0(1,i) - XX0(1,i)) - e) < 0.6754*sqrt(s12)
( i( s+ x5 R8 L V% l cout = cout+1;) \) n, U2 Q+ R" H6 k" s
else
/ V3 n! A# n) T' j$ l cout = cout;0 b/ j+ r: P: @8 |4 _
end
' R! b, e$ N& i: I* `( |; bend; h( s0 V+ x5 O+ C
P = cout / n;
& C* K2 p& j: R; r- m$ pP7 ?( U- X9 E% G
if (C < 0.35 & P > 0.95): h, o% C: E7 N# f* _2 u% v
disp('预测精度为一级');
. g3 M+ {" Z% F- \% f z- t m = input('请输入需要预测的年数: m = '); %预测往后各年的负荷
, v( ]4 N, \6 ]8 R8 _& ]/ I! q disp('往后m各年负荷为:');" F( f; d& V" Q. I. @4 D
f = zeros(1,m);9 ?" B2 F6 U0 P1 J1 R1 ]
for i = 1:m
. |$ n0 j* i( ]2 m6 \ f(1,i) = (X0(1,1) - u/a)*(1-exp(a))*exp(-a*(i+n-1));: ^" o$ c! V# L( t: O9 t* ^/ W& d. h. p
end* g/ A: K- a8 u6 u. M5 {
f
3 b4 S) a: p7 b' w% _0 `8 Pelse
8 H% t6 W- c+ a6 r disp('灰色预测法不适用');, l2 l' r3 u! ~) K( ^3 M
end |