gamma

gamma function in javascript using the lanczos approximation for small values and the spouge approximation for larger values

example

> var gamma = require('gamma')
> gamma(5)
23.999999999999996
> gamma(1.6)
0.8935153492876909

methods

var gamma = require('gamma')

gamma(z)

Return the gamma function over z. Complex numbers aren't supported, only reals.

gamma.log(z)

Return the natural log of the gamma function for z.

This function is used internally by the spouge approximation to compute large values.

install

With npm do:

npm install gamma

kudos

Implementation transliterated from the python script on the wikipedia entry for the lanczos approximation.

Spouge approximation from Niggler.

license

MIT