import tensorflow as tf


pi = tf.constant(np.pi, dtype=tf.float64, name="pi")
sqrt2pi = tf.constant(np.sqrt(2 * np.pi), dtype=tf.float64, name="sqrt2pi")
two = tf.constant(2, dtype=tf.float64, name="two")
one = tf.constant(1, dtype=tf.float64, name="one")
zero = tf.constant(0, dtype=tf.float64, name="zero")


def gradsafe_sqrt(x, clip_low=1e-18, name=None):
    with tf.name_scope(name, "gradsafe_sqrt"):
