Trait LambertW

pub trait LambertWwhere
    Self: Sized,{
    // Required methods
    fn lambert_w0(self) -> Self;
    fn lambert_wm1(self) -> Self;
}

Expand description

Lambert W functions.

Required Methods§

Compute the real-valued parts of the princial branch of the Lambert W function.

This function is the inverse of the function

f(w) = we^w

when w >= -1.

The implementation is based on lambert_w by Johanna Sörngård.

use special::LambertW;

let Ω: f64 = 0.5671432904097838;
assert!((1.0.lambert_w0() - Ω).abs() < 1e-15);

T. Fukushima, Precise and fast computation of Lambert W function by piecewise minimax rational function approximation with variable transformation.

Compute the real-valued parts of the secondary branch of the Lambert W function.

This function is the inverse of the function

f(w) = we^w

when w < -1.

The implementation is based on lambert_w by Johanna Sörngård.

use special::LambertW;

assert!(((-f64::ln(2.0) / 2.0).lambert_wm1() + f64::ln(4.0)).abs() < 1e-15);

T. Fukushima, Precise and fast computation of Lambert W function by piecewise minimax rational function approximation with variable transformation.

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.