jct/trueskill
1
0
Fork 0
mirror of https://github.com/furyfire/trueskill.git synced 2025-03-20 16:48:04 +00:00
Code Issues Packages Projects Releases Wiki Activity

First TwoPlayerTrueSkillCalculator unit test passed

Browse Source
This commit is contained in:
Jeff Moser
2010-08-28 22:05:41 -04:00
commit 12a02b8403
41 changed files with 1909 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

105
PHPSkills/Elo/TwoPlayerEloCalculator.php Normal file
View File

@ -0,0 +1,105 @@
<?php
namespace Moserware\Skills\Elo;
require_once(dirname(__FILE__) . "/../PairwiseComparison.php");
require_once(dirname(__FILE__) . "/../RankSorter.php");
require_once(dirname(__FILE__) . "/../SkillCalculator.php");
require_once(dirname(__FILE__) . "/../PlayersRange.php");
require_once(dirname(__FILE__) . "/../TeamsRange.php");
use Moserware\Skills\PairwiseComparison;
use Moserware\Skills\RankSorter;
use Moserware\Skills\SkillCalculator;
use Moserware\Skills\SkillCalculatorSupportedOptions;
use Moserware\Skills\PlayersRange;
use Moserware\Skills\TeamsRange;
abstract class TwoPlayerEloCalculator extends SkillCalculator
{
protected $_kFactor;
protected function __construct(KFactor $kFactor)
{
parent::__construct(SkillCalculatorSupportedOptions::NONE, TeamsRange::exactly(2), PlayersRange::exactly(1));
$this->_kFactor = $kFactor;
}
public function calculateNewRatings($gameInfo,
array $teamsOfPlayerToRatings,
array $teamRanks)
{
$this->validateTeamCountAndPlayersCountPerTeam($teamsOfPlayerToRatings);
RankSorter::sort($teamsOfPlayerToRatings, $teamRanks);
$result = array();
$isDraw = ($teamRanks[0] === $teamRanks[1]);
$team1 = $teamsOfPlayerToRatings[0];
$team2 = $teamsOfPlayerToRatings[1];
$player1 = each($team1);
$player2 = each($team2);
$player1Rating = $player1["value"]->getMean();
$player2Rating = $player2["value"]->getMean();
$result[$player1["key"]] = $this->calculateNewRating($gameInfo, $player1Rating, $player2Rating, $isDraw ? PairwiseComparison::DRAW : PairwiseComparison::WIN);
$result[$player2["key"]] = $this->calculateNewRating($gameInfo, $player2Rating, $player1Rating, $isDraw ? PairwiseComparison::DRAW : PairwiseComparison::LOSE);
return $result;
}
protected function calculateNewRating($gameInfo, $selfRating, $opponentRating, $selfToOpponentComparison)
{
$expectedProbability = $this->getPlayerWinProbability($gameInfo, $selfRating, $opponentRating);
$actualProbability = $this->getScoreFromComparison($selfToOpponentComparison);
$k = $this->_kFactor->getValueForRating($selfRating);
$ratingChange = $k * ($actualProbability - $expectedProbability);
$newRating = $selfRating + $ratingChange;
return new EloRating($newRating);
}
private static function getScoreFromComparison($comparison)
{
switch ($comparison)
{
case PairwiseComparison::WIN:
return 1;
case PairwiseComparison::DRAW:
return 0.5;
case PairwiseComparison::LOSE:
return 0;
default:
throw new Exception("Unexpected comparison");
}
}
public abstract function getPlayerWinProbability($gameInfo, $playerRating, $opponentRating);
public function calculateMatchQuality($gameInfo, array $teamsOfPlayerToRatings)
{
validateTeamCountAndPlayersCountPerTeam($teamsOfPlayerToRatings);
$team1 = $teamsOfPlayerToRatings[0];
$team2 = $teamsOfPlayerToRatings[1];
$player1 = $team1[0];
$player2 = $team2[0];
$player1Rating = $player1[1]->getMean();
$player2Rating = $player2[1]->getMean();
$ratingDifference = $player1Rating - $player2Rating;
// The TrueSkill paper mentions that they used s1 - s2 (rating difference) to
// determine match quality. I convert that to a percentage as a delta from 50%
// using the cumulative density function of the specific curve being used
$deltaFrom50Percent = abs(getPlayerWinProbability($gameInfo, $player1Rating, $player2Rating) - 0.5);
return (0.5 - $deltaFrom50Percent) / 0.5;
}
}
?>