Class games.Rating.Rating 
All Packages  Class Hierarchy  This Package  Previous  Next  Index

Class games.Rating.Rating 

java.lang.Object
   |
   +----games.Rating.Rating
public class Rating
extends Object
The Rating class implements the Glicko Rating System, devised by Mark Glickman to replace the Elo system that is currently used to rate chess matches.

The advantage of this system is that there is no ad-hoc "wild period" of some number of games that it takes the player to become established. In the Elo system this method is used to account for the need to quickly get the players rating into the right ballpark, by allowing huge swings before using the normal updating algorithm. Instead, the Glickman system uses a Rating and a Rating Deviation, which may be thought of as similar to a mean and a standard deviation in a normal distribution. Initially the Rating is in the centre of the 0-3000 range, and the deviation is quite high (350); as the player plays more and more games the rating and the deviation settle down. Once the deviation is small the player is assured of having a reasonably accurate estimate of their strength in the game.

Ratings adjustments are always based on a win-loss system. To simulate a draw, it is necessary to adjust the ratings as though there was one win and one loss, which is not currently supported by this code.

For details of how the rating system works, see Mark Glickman's home page .

Constructor Index

o Rating()
Constructs a default rating for an unknown player.
o Rating(int, int)
Constructs a particular rating for a known player.
o Rating(String)
Constructs a particular rating for a known player, from the string representation of the rating, for example, "1500/350".

Method Index

o calculateRatings(Rating[])
Adjust ratings to reflect the result of a match or a tournament.
o getRating()
Returns this rating in double precision.
o getRatingDeviation()
Returns this rating's deviation in double precision.
o toString()
Convert the rating to an integer representation embedded in a string, for exmaple, 1500/350.

Constructors

o Rating 
  public Rating()
Constructs a default rating for an unknown player.
o Rating 
  public Rating(int mu,
                int sigma)
Constructs a particular rating for a known player.
o Rating 
  public Rating(String stringRep)
Constructs a particular rating for a known player, from the string representation of the rating, for example, "1500/350". Assumes that the string representation records the rating with integers.

Methods

o getRating 
  public double getRating()
Returns this rating in double precision.
o getRatingDeviation 
  public double getRatingDeviation()
Returns this rating's deviation in double precision.
o calculateRatings 
  public static void calculateRatings(Rating player[])
Adjust ratings to reflect the result of a match or a tournament. The input is an array of ratings, where the 0th entry is the winner of the game, the 1st player is in second place, and so on. All ratings are adjusted simultaneously to reflect the oucome of the game, so this is suitable for evaluating the result of a multiplayer game where all players competed simultaneously, or to adjust after a tournament.
Parameters:
player - the array of players to be adjusted.
o toString 
  public String toString()
Convert the rating to an integer representation embedded in a string, for exmaple, 1500/350.
Overrides:
toString in class Object 
All Packages  Class Hierarchy  This Package  Previous  Next  Index