function to resolve Ax=B

Hello, Can you help me to resolve Ax=B by gauss elimination in matlab with

A =
-2.1000 -0.5000 -0.9000 -1.9000  1.2000  0.1000
 0.6000  0      -1.9000  2.4000 -1.7000  0.2000
 2.0000 -0.5000  0      -0.2000  0.4000 -0.5000
 2.2000  0.1000  1.2000  0.4000  0.5000  0.7000
 3.3800  0.6400 -3.4100  4.0800 -1.8900  1.4600
-0.2300 -0.1900  0.2300  2.6700 -2.7600 -1.1300
-0.6400 -0.1400 -1.0500  0.0200 -0.0200  0.2200

b =
-0.8000
-0.8000
 0.7000
 1.7000
 1.4000
-2.3600
-0.4600

Here is what i have done , but i have an error : Index in position 2 exceeds array bounds (must not exceed 7).

function x = GAUSS_ELIM(A, b)
%% Create permutation vector
n = size(A, 1); % Size of input matrix
r = zeros(n, 1); % Initialize permutation vector
for i = 1 : 1 : n
r(i) = i;
end
%% Apply Gaussian elimination and rearrange permutation vector
x = zeros(n, 1); % Initialize solution vector
for k = 1 : 1 : n % Go through each element in permutation vector
% Compare each element in r(k)th column for the max
max = abs(A(r(k), r(k)));
max_pos = k;
for l = k : 1 : n
if abs(A(r(l), r(k))) > max
max = abs(A(r(l), r(k)));
max_pos = l;
end
end
% Switch the kth r-vector element with max r-vector element
temp_r = r;
r(k) = temp_r(max_pos);
r(max_pos) = temp_r(k);
% Eliminate A-vector elements in r(k)th column below r(k)th row
for i = 1 : 1 : n
if i ~= k
zeta = A(r(i), k) / A(r(k), k);
for j = k : 1 : n
A(r(i), j) = A(r(i), j) - A(r(k), j) * zeta;
end
b(r(i)) = b(r(i)) - b(r(k)) * zeta;
end
end
end
% Compute the solution frpm the diagonalized A-matrix
for i = 1 : 1 : n
x(i) = b(r(i)) / A(r(i), i);
end
end

[dpb]

1. Indent your code so it can be read more easily
2. first loop isn't needed--replace

r = zeros(n, 1); % Initialize permutation vector
for i = 1 : 1 : n
r(i) = i;
end

with

r=[1:n].';  % initialize permutation vector

Isn't your problem, but may as well use MATLAB syntax, it is after all, "MATrix LABoratory".

3. You didn't tell where the error occurs, even.

[amine aquesbi]

Wow I didn't see that we could write the code this way ! It's much better thanks !

And yes sorry, the error is :

Index in position 2 exceeds array bounds (must not exceed 7).

Error in gauss (line 65)
           A(j,k) = A(j,k) - m*A(i,k);

[dpb]

OK, so k is outside bounds of A.

BUT, that error is for a function gauss while your function above is named |GAUSS_ELIM| and the above code line doesn't exist in that function.

You're debugging/executing different function than you think you are, apparently.

[amine aquesbi]

yes sorry again , it's because Im working with 2 differents function , here is the error :

Index in position 2 exceeds array bounds (must not exceed 6).

Error in GAUSS_ELIM (line 57)
A(r(i), j) = A(r(i), j) - A(r(k), j) * zeta;