hi am working on a code for gaussian elimination

14 次查看（过去 30 天）
Ifechukwu
Ifechukwu 2014-5-22
编辑： Walter Roberson 2016-7-17
hi am working on a code for gaussian elimination but I can't get the code to run for non square matrix please what should I do Here is the code and thanks in advance
function [x,U] = gausselim(A,b)
% function to perform gauss eliminination
%FORWARD ELIMINATION
n=length(b);
m=zeros(n,1);
x=zeros(n,1);
for k =1:n-1;
%compute the kth column of M
m(k+1:n) = A(k+1:n,k)/A(k,k);
%compute An=Mn*An-1, bn=Mn*bn-1
for i=k+1:n;
A(i, k+1:n) = A(i,k+1:n)-m(i)*A(k,k+1:n);
end;
b(k+1:n)=b(k+1:n)-b(k)*m(k+1:n);
end;
U= triu(A);
%BACKWARD ELIMINATION
x(n)=b(n)/A(n,n);
for k =n-1:-1:1;
b(1:k)=b(1:k)-x(k+1)* U(1:k,k+1);
x(k)=b(k)/U(k,k);
end;
end
  1 个评论
John D'Errico
John D'Errico 2014-5-22
I fixed it for you, but you need to learn how to flag a block of code as such. Otherwise, it is unreadable.

请先登录，再进行评论。

请先登录，再回答此问题。

采纳的回答

George Papazafeiropoulos
编辑：Walter Roberson 2016-7-17
The correct function is:
function [x,U]=gausselim(A,b)
% function to perform gauss eliminination
%FORWARD ELIMINATION
n=length(b);
m=zeros(n,1);
x=zeros(n,1);
for k =1:n-1;
%compute the kth column of M
m(k+1:n) = A(k+1:n,k)/A(k,k);
%compute
%An=Mn*An-1;
%bn=Mn*bn-1;
for i=k+1:n
A(i, k+1:n) = A(i,k+1:n)-m(i)*A(k,k+1:n);
end;
b(k+1:n)=b(k+1:n)-b(k)*m(k+1:n);
end
U= triu(A);
%BACKWARD ELIMINATION
x(n)=b(n)/A(n,n);
for k =n-1:-1:1;
b(1:k)=b(1:k)-x(k+1)* U(1:k,k+1);
x(k)=b(k)/U(k,k);
end
end
After this try to run the code:
A=rand(5,4);
b=rand(4,1);
[x,U] = gausselim(A,b)
Is this what you want? I hope this helps...
George

更多回答（1 个）

Cory Cress
Cory Cress 2016-7-17
编辑：Walter Roberson 2016-7-17
I think the command you are looking for is rref :
R = rref(A)
[R,jb] = rref(A)
[R,jb] = rref(A,tol)
It produces a matrix in reduced row echelon form. Perhaps your exercise was to write it yourself, but for others that want to use a built-in function use rref.

类别

在 Help Center 和 File Exchange 中查找有关 Linear Algebra 的更多信息

标签

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by