Function cont_arith_code::distribution::gaussian::log_probability

pub fn log_probability(lo: f64, hi: f64) -> f64

Returns a numerically stable log(abs(cdf(hi) - cdf(lo))) for the standard normal. Should only return log(0.0) if the bounds are the same or if the log-PDF at their mid point is f64::NEG_INFINITY (or almost).