cos4\theta

[sycophant-stone]

since
cos(4\theta )=8cos^4\theta-8cos^2\theta+2

why do i care the sign of cos\theta?

thanks

 cos_theta = tf.div(selected_logits, embeddings_norm)
            cos_theta_power = tf.square(cos_theta)
            cos_theta_biq = tf.pow(cos_theta, 4)
            sign0 = tf.sign(cos_theta)
            sign3 = tf.multiply(tf.sign(2*cos_theta_power-1), sign0)
            sign4 = 2*sign0 + sign3 -3
            result=sign3*(8*cos_theta_biq-8*cos_theta_power+1) + sign4