code: def _normal_cdf_difference(x, y):
      """Computes ndtr(x) - ndtr(y) assuming that x >= y."""
      # When x >= y >= 0, we will return ndtr(-y) - ndtr(-x)
      # because ndtr does not have a good precision for large positive x, y.
      is_y_positive = y >= 0
      x_hat = tf.where(is_y_positive, -y, x)
      y_hat = tf.where(is_y_positive, -x, y)
      return special_math.ndtr(x_hat) - special_math.ndtr(y_hat)
  
imports: import numpy
  import tensorflow.compat.v2
  from tensorflow_probability.python.bijectors import sigmoid
  from tensorflow_probability.python.bijectors import softplus
  from tensorflow_probability.python.distributions import distribution
  from tensorflow_probability.python.internal import assert_util
  from tensorflow_probability.python.internal import dtype_util
  from tensorflow_probability.python.internal import parameter_properties
  from tensorflow_probability.python.internal import prefer_static
  from tensorflow_probability.python.internal import reparameterization
  from tensorflow_probability.python.internal import samplers
  from tensorflow_probability.python.internal import special_math
  from tensorflow_probability.python.internal import tensor_util
  from tensorflow_probability.python.math.generic import log_sub_exp
label_desc: Use image node_id 3 for calling a global function with example usage: _normal_cdf_difference(x, y) and returns: unknown