Lambert W

Ben Bolker's port of Lambert W from GNU Scientific Library (GPLV3)

Usage

lambertW(z, b = 0, maxiter = 10, eps = .Machine$double.eps, min.imag = 1e-09)

Arguments

z

input value

b

branch, set to principal by default

maxiter

Halley iteration count

eps

error precision

min.imag

minimum for imaginary solution

Value

numeric

Details

Ben Bolker's port of Lambert W from GNU Scientific Library

Author

Benjamin Bolker (port)

Examples

## Principal branch: W(1) ~ 0.5671
lambertW(1)
#> [1] 0.5671433

## Verify: W(z) * exp(W(z)) == z
w <- lambertW(2)
w * exp(w)
#> [1] 2