Donja trougaona matrica

function A = donja_trougaona(A)
    [rows, cols] = size(A);

    if (rows~=cols)
        return;
    end

    for k = rows:-1:2
       for i = k-1:-1:1
          coefficient = (-1)*A(i,k)/A(k,k);
          for j = 1:k
              A(i, j) = A(i, j) + coefficient*A(k,j);
          end
       end
    end
end