pub fn log_ndtr(x: f64) -> f64Expand description
log Φ(x) for the standard normal CDF, the host oracle for the device
log_ndtr. For x < 0 uses the erfcx representation
log Φ(x) = −u² + log(½·erfcx(u)), u = −x/√2, keeping digits into the
deep left tail; for x ≥ 0 uses log(½·erfc(−x/√2)) with the same clamps as
the kernel. Propagates ±∞/NaN exactly as the device path does.