def METHOD_NAME(x, x_adv):
    """
    Return the absolute SNR of x to (x - x_adv), with range [0, inf]
        If there is no adversarial perturbation, always return inf
    """
    signal_power = (np.abs(x) ** 2).mean()
    noise_power = (np.abs(x - x_adv) ** 2).mean()
    if noise_power == 0:
        return np.inf
    else:
        return signal_power / noise_power