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[综合讨论] 帮我看看 AX=B?

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发表于 2006-9-1 17:50 | 显示全部楼层 |阅读模式

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x
A是10X100维  X是100X1维   B是10X1维, 然后计算 X

for i=1:10,  u1(i)= sum(A(i,:)); end
u1=u1';

for j=1:100,  u2(j)= sum(A(:,j)); end
u2=u2';

    for i=1:10, A1(i,:)= A(i,:)*B(i)/u1(i); end
    for j=1:100, u3(j)= sum(A1(:,j)); end
u3=u3';

for j=1:100, x(j)= u3(j)/(u2(j)+eps); end

或者有更好的方法吗~~ 帮偶看看  :@(

[ 本帖最后由 ChaChing 于 2010-4-10 20:33 编辑 ]
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发表于 2010-7-9 11:01 | 显示全部楼层
直接A\B即可! :@)
from matlab help :
If A is an m-by-n matrix with m ~= n and B is a column vector with m components, or a matrix with several such columns, then X = A\B is the solution in the least squares sense to the under- or overdetermined system of equations AX = B.

还有LZ的写法, 值得精进, 数值算法忘了精光, 仅就编程说说
u1=sum(A')'; %for i=1:10, u1(i)=sum(A(i,:)); end; u1=u1';
u2=sum(A)'; %for j=1:100, u2(j)=sum(A(:,j)); end; u2=u2';
u3=((B./u1)'*A)'; %for i=1:10, A1(i,:)= A(i,:)*B(i)/u1(i); end
%for j=1:100, u3(j)= sum(A1(:,j)); end; u3=u3';
x=u3./u2; %for j=1:100, x(j)= u3(j)/(u2(j)+eps); end
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