Fibonacci method optimization

function x = fibonacci_method_optimization(a, b, max_error, my_function)

    max_iter = -2;
    fibonacci_a = 1;
    fibonacci_b = 1;
    condition = (b - a)/max_error;

    while fibonacci_b < condition
        t = fibonacci_b;
        fibonacci_b = fibonacci_b + fibonacci_a;
        fibonacci_a = t;
        max_iter = max_iter + 1;
    end

    if fibonacci_a > condition || fibonacci_b < condition
        x = NaN;
        return;
    end

    for i = 1:max_iter

        x_1 = a + ((fibonacci_b - fibonacci_a)/fibonacci_b)*(b - a);
        x_2 = a + b - x_1;

        if feval(my_function, x_1) > feval(my_function, x_2)
            a = x_1;
        elseif feval(my_function, x_2) > feval(my_function, x_1)
            b = x_2;
        else
            % Novi par tacaka ?
            a = x_1;
            b = x_2;
        end

    end

    x = (a+b)/2;

end