Added todo to readme, and documentation for quality function

README.md

@@ -15,6 +15,7 @@ Rust port of [TrueSkillThroughTime.py](https://github.com/glandfried/TrueSkillTh
 
 - [x] Implement approx for Gaussian
 - [x] Add more tests from `TrueSkillThroughTime.jl`
+- [ ] Add tests for `quality()` (Use [sublee/trueskill](https://github.com/sublee/trueskill/tree/master) as reference)
 - [ ] Benchmark Batch::iteration()
 - [ ] Time needs to be an enum so we can have multiple states (see `batch::compute_elapsed()`)
 - [ ] Add examples (use same TrueSkillThroughTime.(py|jl))

src/lib.rs

@@ -256,6 +256,7 @@ pub(crate) fn evidence(d: &[DiffMessage], margin: &[f64], tie: &[bool], e: usize
     }
 }
 
+/// Calculates the match quality of the given rating groups. A result is the draw probability in the association
 pub fn quality(rating_groups: &[&[Gaussian]], beta: f64) -> f64 {
     let flatten_ratings = rating_groups
         .iter()