Does anyone know how to write a program in MATLAB to perform

Does anyone know how to write a program in MATLAB to perform Gauss Elimination (not naïve) for a system of linear equations Ax = b?

Solution

Following is the program in MATLAB to perform Gauss Elimination

function x = gauss(A,b)
A = cat(2,A,b);
[m,n]=size(A);
for j=1:m-1
    for z=2:m
        if A(j,j)==0
            t=A(j,:);A(j,:)=A(z,:);
            A(z,:)=t;
        end
    end
    for i=j+1:m
        A(i,:)=A(i,:)-A(j,:)*(A(i,j)/A(j,j));
    end
end
x=zeros(1,m);
for s=m:-1:1
    c=0;
    for k=2:m
        c=c+A(s,k)*x(k);
    end
    x(s)=(A(s,n)-c)/A(s,s);
end
disp(\'Gauss elimination method:\');
A
x\'
end

Sample Input:

A= [0.25 0.35 0.55
0.35 0.2 0.4
0.4 0.45 0.05]

b=[0.3
0.3
0.4]

gauss(A,b)

Sample Output

Gauss elimination method:

A =

    0.2500    0.3500    0.5500    0.3000
         0 -0.2900   -0.3700   -0.1200
         0           0        -0.6897   -0.0345

ans =

    0.6000
    0.3500
    0.0500