A small implementation of the ELO rating system in Ruby.

Authors: Anna Sheaffer @anna2, Rishi Ghosh

A Ruby implementation of the ELO Player Rating system. The method below handles all aspects of calculating the new ELO ratings for both players. Object Oriented use supported.

• Description: Returns an array with keys "Player1" and "Player2" holding corresponding new ELO ratings.
• Examples: No examples yet.
• Parmeters:
  • player1_rating: Rating of Player1 right before match.
  • player2_rating: Rating of Player2 right before match.
  • k_value: The constant K-value used in developers ELO system. Read the wikipedia article on ELO for details.
  • result: The result of the match on a scale of 0 to 1. "0" = Player1 lost, Player 2 won. "0.5" = Draw. "1" = Player 1 won, Player 2 lost.
  • should_round: Set to "true" by default. Rounds the output ratings.

require 'elo.rb'

# Object Oriented Example
tom = RatedPlayer.new("Tom",1600)
alan = RatedPlayer.new("Alan",2000)
puts tom.rating
puts alan.rating
Match.new(tom,alan,1)
puts tom.rating
puts alan.rating

Output:
1600
2000
1629
1971