left and right sides have a different number of elements

im trying to solve a gauss-seidel method problem and im getting the "left and right sides have a different number of elements" error in the xn(Iter) lines. how do i fix this?

A = [10 -2 -5 30; -2 15 -5 -5; -5 -5 14 25]
C = [2 ; 1 ; 3]

Error = 100;
Thr = 1;
Iter = 0;

x1 = C(1,1);
x2 = C(2,1);
x3 = C(3,1);

while Iter<5

    Iter = Iter+1;

    x1(Iter) = (A(1,4) - A(1,2)*x2 - A(1,3)*x3)/A(1,1);
    x2(Iter) = (A(2,4) - A(2,1)*x1 - A(2,3)*x3)/A(2,2);
    x3(Iter) = (A(3,4) - A(3,1)*x1 - A(3,2)*x2)/A(3,3);

    x1 = x1(Iter);
    x2 = x2(Iter);
    x3 = x3(Iter);

    
end

[Torsten]

You cannot use x1,x2 and x3 as a scalar and simultaneously as an array. Make up a decision for one of the two ways.

And what about x4 ? Your matrix A is 3x4 ! I've never heard of Gauss-Seidel for non-square systems...

Answer 1

[Matt J]

A = [10 -2 -5 30; -2 15 -5 -5; -5 -5 14 25];
C = [2 ; 1 ; 3];

Error = 100;
Thr = 1;
Iter = 0;

x1 = C(1,1);
x2 = C(2,1);
x3 = C(3,1);

while Iter<5

    Iter = Iter+1;

    X1(Iter) = (A(1,4) - A(1,2)*x2 - A(1,3)*x3)/A(1,1);
    X2(Iter) = (A(2,4) - A(2,1)*x1 - A(2,3)*x3)/A(2,2);
    X3(Iter) = (A(3,4) - A(3,1)*x1 - A(3,2)*x2)/A(3,3);

    x1 = X1(Iter);
    x2 = X2(Iter);
    x3 = X3(Iter);

    
end
X1,X2,X3

X1 = 1×5

4.7000 4.6152 5.1480 5.2490 5.4178

X2 = 1×5

0.9333 1.2457 1.5479 1.6460 1.7589

X3 = 1×5

2.8571 3.7976 3.8789 4.1771 4.2482