Function qfuncinv 

pub fn qfuncinv(p: f64) -> f64

Inverse of qfunc on $(0, 1)$: $Q^{-1}(p) = \sqrt{2}, \operatorname{erfc}^{-1}(2p)$ (±∞ at the ends).

Examples

use comnum_math::{qfunc, qfuncinv};
assert!((qfuncinv(0.025) - 1.959_964).abs() < 1e-6);
assert!((qfunc(qfuncinv(1e-6)) / 1e-6 - 1.0).abs() < 1e-9);