skillratings

Skillratings allows you to calculate the player's skill in 1v1 matches instantly.
Only player-versus-player matches are currently supported, no teams. Instead of calculating results at the end of rating periods, we deliver the result instantly after a match.

Currently supported algorithms:

• Elo
• Glicko
• Glicko-2
• TrueSkill
• DWZ (Deutsche Wertungszahl)
• Ingo

These are mainly known from their usage in chess and online games.

Installation

Add the following to your Cargo.toml file:

[dependencies]

skillratings = "0.7.0"

Usage

For a detailed guide on how to use this crate, head over to the documentation.

Elo rating system

Wikipedia article

extern crate skillratings;

use skillratings::{elo::elo, outcomes::Outcomes, rating::EloRating};

let player_one = EloRating { rating: 1000.0 };
let player_two = EloRating { rating: 1000.0 };

// The outcome is from the perspective of player one.
let outcome = Outcomes::WIN;

let (player_one_new, player_two_new) = elo(player_one, player_two, outcome, 32.0);
assert!((player_one_new.rating - 1016.0).abs() < f64::EPSILON);
assert!((player_two_new.rating - 984.0).abs() < f64::EPSILON);

Glicko rating system

Wikipedia article

use skillratings::{glicko::glicko, outcomes::Outcomes, rating::GlickoRating};

let player_one = GlickoRating {
    rating: 1500.0,
    deviation: 350.0,
};
let player_two = GlickoRating {
    rating: 1500.0,
    deviation: 350.0,
};

let outcome = Outcomes::WIN;

let (player_one_new, player_two_new) = glicko(player_one, player_two, outcome);

assert!((player_one_new.rating.round() - 1662.0).abs() < f64::EPSILON);
assert!((player_one_new.deviation.round() - 290.0).abs() < f64::EPSILON);

assert!((player_two_new.rating.round() - 1338.0).abs() < f64::EPSILON);
assert!((player_two_new.deviation.round() - 290.0).abs() < f64::EPSILON);

Glicko-2 rating system

Wikipedia article

extern crate skillratings;

use skillratings::{glicko2::glicko2, outcomes::Outcomes, rating::Glicko2Rating};

let player_one = Glicko2Rating { 
    rating: 1500.0, 
    deviation: 350.0, 
    volatility: 0.06 
};
let player_two = Glicko2Rating { 
    rating: 1500.0, 
    deviation: 350.0, 
    volatility: 0.06 
};

let outcome = Outcomes::WIN;

let (player_one_new, player_two_new) = glicko2(player_one, player_two, outcome, 0.5);

assert!((player_one_new.rating.round() - 1662.0).abs() < f64::EPSILON);
assert!((player_one_new.deviation.round() - 290.0).abs() < f64::EPSILON);

assert!((player_two_new.rating.round() - 1338.0).abs() < f64::EPSILON);
assert!((player_two_new.deviation.round() - 290.0).abs() < f64::EPSILON);

TrueSkill rating system

Wikipedia article

Caution regarding usage of TrueSkill: Microsoft permits only Xbox Live games or non-commercial projects to use TrueSkill(TM). If your project is commercial, you should use another rating system included here.

use skillratings::{trueskill::trueskill, outcomes::Outcomes, rating::TrueSkillRating};

// Initialises a player with `rating` set to 25.0 and `uncertainty` set to (25.0 / 3).
let player_one = TrueSkillRating::new();
let player_two = TrueSkillRating {
    rating: 30.0,
    uncertainty: 1.2,
};

let (p1, p2) = trueskill(player_one, player_two, Outcomes::WIN);

assert!(((p1.rating * 100.0).round() - 3300.0).abs() < f64::EPSILON);
assert!(((p1.uncertainty * 100.0).round() - 597.0).abs() < f64::EPSILON);

assert!(((p2.rating * 100.0).round() - 2983.0).abs() < f64::EPSILON);
assert!(((p2.uncertainty * 100.0).round() - 120.0).abs() < f64::EPSILON);

DWZ (Deutsche Wertungszahl) rating system

Wikipedia article

use skillratings::{dwz::dwz, outcomes::Outcomes, rating::DWZRating};

let player_one = DWZRating {
    rating: 1500.0,
    index: 42,
    age: 42,
};
let player_two = DWZRating {
    rating: 1500.0,
    index: 12,
    age: 12,
};

let outcome = Outcomes::WIN;

let (player_one_new, player_two_new) = dwz(player_one, player_two, outcome);

assert!((player_one_new.rating.round() - 1519.0).abs() < f64::EPSILON);
assert_eq!(player_one_new.index, 43);

assert!((player_two_new.rating.round() - 1464.0).abs() < f64::EPSILON);
assert_eq!(player_two_new.index, 13);

Ingo rating system

Wikipedia article (in german, no english version available)

use skillratings::{ingo::ingo, outcomes::Outcomes, rating::IngoRating};

let player_one = IngoRating {
    // Note that a lower rating is more desirable.
    rating: 130.0,
    age: 40,
};
let player_two = IngoRating {
    rating: 160.0,
    age: 40,
};

let (p1, p2) = ingo(player_one, player_two, Outcomes::WIN);

assert!((p1.rating.round() - 129.0).abs() < f64::EPSILON);
assert!((p2.rating.round() - 161.0).abs() < f64::EPSILON);

License

This project is licensed under the MIT License.