I cannot use the lugauss function to calculate L and U factors from matrix A. Please help!

I have attached my operating code and here is the lugauss funciton:

function A=lugauss(A)

%LUGAUSS LU factorization without pivoting.

% A = LUGAUSS(A) stores an upper triangular matrix in

% the upper triangular part of A and a lower triangular

% matrix in the strictly lower part of A (the diagonal

% elements of L are 1).

[n,m]=size(A);

if n ~= m; error('A is not a square matrix'); else

for k = 1:n-1

for i = k+1:n

A(i,k) = A(i,k)/A(k,k);

if A(k,k) == 0, error('Null diagonal element '); end

j = [k+1:n]; A(i,j) = A(i,j) - A(i,k)*A(k,j);

end

end

end