LambertW

[Henryk Trappmann]

has Sage the Lambert W function implemented?
I can not find it.

[William Stein]

2009/8/28 Henryk Trappmann <bo19...@googlemail.com>:

>
> has Sage the Lambert W function implemented?
> I can not find it.

It does, but via mpmath:

sage: mpmath.lambertw(10)
mpf('1.7455280027406994')
sage: import mpmath
sage: mpmath.lambertw(complex(2,3))
mpc(real='1.0900765344857908', imag='0.53013972077483884')
sage: mpmath.lambertw?
pages and pages of examples and docs!

William

[William Stein]

2009/8/28 William Stein <wst...@gmail.com>:

> 2009/8/28 Henryk Trappmann <bo19...@googlemail.com>:
>>
>> has Sage the Lambert W function implemented?
>> I can not find it.
>
> It does, but via mpmath:

By the way, do

sage: import mpmath

first.

>
> sage: mpmath.lambertw(10)
> mpf('1.7455280027406994')
> sage: import mpmath
> sage: mpmath.lambertw(complex(2,3))
> mpc(real='1.0900765344857908', imag='0.53013972077483884')
> sage: mpmath.lambertw?
> pages and pages of examples and docs!
>
> William
>

--
William Stein
Associate Professor of Mathematics
University of Washington
http://wstein.org

[Ondrej Certik]

or through sympy:

sage: import sympy
sage: sympy.LambertW(x)
LambertW(x)
sage: sympy.integrate(sympy.LambertW(x))
-x + x*LambertW(x) + x/LambertW(x)

Ondrej

[Henryk Trappmann]

oh thanks. The mpmath is even capable of the complex branches.