This library provides Polygamma function. It is forked from http://www.rd.dnc.ac.jp/~tunenori/src/polygamma.c
```rust use polygamma::polygamma;
fn main() { println!("digamma(1.0) = {}", polygamma(0, 1.0).unwrap()); println!("trigamma(1.0) = {}", polygamma(1, 1.0).unwrap()); } ```