gamma function in javascript using the lanczos approximation for small values and the spouge approximation for larger values
> var gamma = require('gamma')
> gamma(5)
23.999999999999996
> gamma(1.6)
0.8935153492876909
var gamma = require('gamma')
Return the gamma function over z. Complex numbers aren't supported, only reals.
Return the natural log of the gamma function for z.
This function is used internally by the spouge approximation to compute large values.
With npm do:
npm install gamma
Implementation transliterated from the python script on the wikipedia entry for the lanczos approximation.
Spouge approximation from Niggler.
MIT