Function inverse_langevin_approximate

pub fn inverse_langevin_approximate(y: f64) -> f64

Returns an approximation of the inverse Langevin function.¹

\mathcal{L}^{-1}(y) \approx \frac{2.14234 y^3 - 4.22785 y^2 + 3y}{(1 - y)(0.71716 y^3 - 0.41103 y^2 - 0.39165 y + 1)}

This approximation has a maximum relative error of $8.2e^{-4}$.

---

1. R. Jedynak, Math. Mech. Solids 24, 1992 (2019). ↩