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渭河小舟

铁虫 (小有名气)

[交流] 【求助】MATLAB计算线性方程组【已解决】

线性方程组形如Xx=Y形式,系数矩阵分别为
X=[11 A B C D E F;A B C D E F G;B C D E F G H;C D E F G H I;D E F G H I J;E F G H I J K;F G H I J K L]
Y=[M P Q R S T U]'
x0=X\Y
x1=inv(X)*Y
p=polyfit(k,f,6)
其中,
A =5264
B =4107392
C =3.6781e+009
D =3.5353e+012
E =3.5435e+015
F =3.6462e+018
G =3.8159e+021
H =4.0382e+024
I =4.3053e+027
J =4.6132e+030
K =4.9603e+033
L =5.3463e+036
M =110
P =78724
Q =68178704
R =6.4323e+010
S =6.3723e+013
T =6.5068e+016
U =6.7747e+019

用MATLAB运行结果如下:
Warning: Matrix is close to singular or badly scaled.
         Results may be inaccurate. RCOND = 2.240578e-037.
(Type "warning off MATLAB:nearlySingularMatrix" to suppress this warning.)
> In C:\MATLAB6p5\work\xiaozhou.m at line 28

x0 =

    0.4048
    0.0496
   -0.0001
   -0.0000
    0.0000
   -0.0000
    0.0000

Warning: Matrix is close to singular or badly scaled.
         Results may be inaccurate. RCOND = 2.240578e-037.
> In C:\MATLAB6p5\work\xiaozhou.m at line 29

x1 =

    0.4048
    0.0496
   -0.0001
   -0.0000
    0.0000
   -0.0000
    0.0000

??? Error using ==> polyfit
X and Y vectors must be the same size.

Error in ==> C:\MATLAB6p5\work\xiaozhou.m
On line 30  ==> p=polyfit(k,f,6)


请教高手如何解决?如何能计算出结果?错误如何处理?非常感谢!

[ Last edited by nono2009 on 2010-1-29 at 10:16 ]
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渭河小舟

铁虫 (小有名气)

woshilsh:哦,呵呵,才发现你的回帖,没事,不删除也可以,方便大家以后问你哈 2010-01-28 22:46
这个问题我自己已经解决,请斑竹将帖子删掉吧,谢谢
3楼2010-01-28 19:55:34
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mjq240301

木虫 (小有名气)

nono2009(金币+1):谢谢应助! 2010-01-28 19:37
你的x、y矩阵大小不一样,就不弄用polyfit命令!
2楼2010-01-28 17:57:40
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