def _log_ndtr_lower(x, series_order):
x_2 = tf.square(x)<EOL>log_scale = -<NUM_LIT:0.5> * x_2 - tf.math.log(-x) - <NUM_LIT:0.5> * np.log(<NUM_LIT> * np.pi)<EOL>return log_scale + tf.math.log(_log_ndtr_asymptotic_series(x, series_order))<EOL>
Asymptotic expansion version of `Log[cdf(x)]`, appropriate for `x<<-1`.