npm install gammagamma 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