package
{/*** Elo排名算法* @author ShuchangLiu*/public class EloRating{public static const ELO_RESULT_WIN:int = 1;public static const ELO_RESULT_LOSS:int = -1;public static const ELO_RESULT_TIE:int = 0;public static const ELO_RATING_DEFAULT:int = 1500;protected var rating1:int;protected var rating2:int;protected var score1:Number;protected var score2:Number;public function EloRating(rating1:int = ELO_RATING_DEFAULT, rating2:int = ELO_RATING_DEFAULT):void{this.rating1 = rating1;this.rating2 = rating2;}/*** @param result ELO_RESULT_WIN or ELO_RESULT_LOSS or ELO_RESULT_TIE*/        public function setResult(result:int):void {var cscore1:Number = computeScore(this.rating2, this.rating1);var cscore2:Number = computeScore(this.rating1, this.rating2);if (result == ELO_RESULT_WIN) {this.rating1 = this.rating1 + (computeK(this.rating1) * (1 - cscore1));this.rating2 = this.rating2 + (computeK(this.rating2) * (0 - cscore2));}else if(result == ELO_RESULT_LOSS) {this.rating1 = this.rating1 + (computeK(this.rating1) * (0 - cscore1));this.rating2 = this.rating2 + (computeK(this.rating2) * (1 - cscore2));}else{// Assume tiethis.rating1 = this.rating1 + (computeK(this.rating1) * (0.5 - cscore1));this.rating2 = this.rating2 + (computeK(this.rating2) * (0.5 - cscore2));}}protected function computeScore($rating1:int, $rating2:int):Number {return (1 / (1 + Math.pow(10, ($rating1 - $rating2) / 400)));}protected function computeK(rating:int):int {if(rating>=2400){return 16;}else if(rating >= 2100){return 24;}else{return 36;}}/** A的获胜期望*/public function getScore1():Number {this.score1 = computeScore(this.rating2, this.rating1);return this.score1;}/** B的获胜期望*/public function getScore2():Number {this.score2 = computeScore(this.rating1, this.rating2);return this.score2;}/** A的排名等级*/public function getRating1():int {return this.rating1;}/** B的排名等级*/public function getRating2():int {return this.rating2;}}
}