matlab 指数函数拟合 [转载]MATLAB数据拟合例子（一次函数 指数函数 双曲线）...

一次函数：(a+bx = y)

%先求出拟合函数

format long;

x = [2001 2002

];

y = [32.2 31.3

29.7 28.6 27.5 26.1 25.3 23.7 22.7];

d = [1 1 1 1 1 1 1 1

1];

a=[d;x];

b = a*y';

a=a*a';

c=ab

c =

1.0e+003 *

2.436797222221444

-0.00166666666

%所以，拟合函数为

y = 1.0e+003

*(2.436797222221444 - 0.00166666666*x

%根据拟合函数求估测值

format short;

x = [, , ,

,

]

1.0e+003

*(2.436797222221444 - 0.00166666666*x)

ans

=

21.4472

20.2456

19.0439

17.8422

16.6406

指数函数：( y = exp(a +

b*x))

>> x = [2001

2002 ];

y =

[21.515.9 11.8

8.76.54.83.52.62.0];

y=log(y');

d = [1 1 1 1 1 1 1 1

1];

a=[d;x];

b = a*y;

a=a*a';

c=ab

c =

601.9448

-0.2993

%所以，拟合函数为 y = exp(601.9448 -

0.2993*x)

%根据拟合函数求估测值

>>x =

[, , , ,]

exp(601.9448 -

0.2993*x)

ans =

1.42161.05390.78130.57920.4294

双曲线： (1/y = a +

b/x)

format long;

x =

[2002 ];

y = [46.232.626.723.020.018.917.516.3];

t=1./x;

u = 1./y';

d = [1 1 1 1 1 1 1 1];

a = [d; t];

b = a*u;

a=a*a';

c=ab

c =

1.0e+004 *

0.001110403638151

-2.218020870743078

format short;

x = [, , ,

,]

x./(1.0e+004 *

(0.001110403638151*x -2.218020870743078))

ans =

14.470413.405912.488211.688810.9862