TrueSkill is a skill-based ranking system developed by Microsoft Research. It is used by Xbox LIVE to rank and match players. This package implements TrueSkill in JavaScript as an npm package.
Import the module.
var trueskill = require('trueskill');
TrueSkill encodes parameters about the game.
var env = new trueskill.TrueSkill({
mu: 25,
sigma: 25 / 3,
beta: 25 / 6,
tau: 25 / 300,
draw: 0.1
});
where
mu: the initial meansigma: the initial standard deviationbeta: the number of skill points to guarantee an 80% chance of winningtau: the dynamics factordraw: the probability of a draw in [0, 1]
Rating encodes a player's rating.
var rating = new trueskill.Rating(mu, sigma);
where
mu: the mean value of the ratingsigma: the standard deviation of the rating
transformRatings calculates updated ratings based prior ratings and the
outcome of a game.
var newRatings = env.transformRatings(
[
{ 'p1': r1, 'p2': r2 },
{ 'p3': r3, 'p4': r4 }
],
[ 2, 1 ]);
where
teams: an array of teams, where each team is a map of player id to prior ratingranks: the ranks of the teams, where 1 indicates the winner
matchQuality calculates the quality of a match as a function of the probability
of all teams drawing.
var quality = env.matchQuality(
[
{ 'p1': r1, 'p2': r2 },
{ 'p3': r3, 'p4': r4 }
]);
where the teams parameter is the same as transformRatings.