If \(tan\left( \frac{\pi}{9} \right),x,tan\left( \frac{7\pi}{18} \right)\) are in arithmetic progression and \(tan\left( \frac{\pi}{9} \right),y,tan\left( \frac{5\pi}{18} \right)\) are also in arithmetic progression, then \(|x - 2y|\) is equal to