lib-elo

Library for ELO calculations for game leagues

Features

• Fully configurable starting rating, k-factor, and xi values
• Support for n-sized teams
• "Exhibition" period: first n games can have and adjustment multiplier in order to move a player to their proper rating faster. Other players will get an inverse multiplier.

Usage

First, start a league by creating a league object with the configuration for the league:

val league = League(kFactorBase = 32, trialKFactorMultiplier = 2)

You will probably want to persist this information within your application so that you can re-create this object at anytime

Next, build the game information objects:

val game = Game(
                id = UUID.randomUUID().toString(),
                team1Score = 10,
                team2Score = 0,
                team1PlayerIds = listOf(player1Id),
                team2PlayerIds = listOf(player2Id),
                entryDate = Instant.now())

Player ids are an identifier supplied by you. Just make sure that the values are consistent for a given player across all games. Then, you can calculate the ratings:

val output : LeagueState = calculateNewLeague(league = league, games = listOf(game))

view the LeagueState class for information on the output. To add more games, you do not need to repeat all of these steps. Simply use the previously calculated LeagueState:

 val updatedResults : LeagueState = addGameToLeague(leagueState = leagueState, game = newGame)