trueskill/PHPSkills/Elo/GaussianEloCalculator.php

26 lines
645 B
PHP

<?php
namespace Moserware\Skills\Elo;
class GaussianEloCalculator extends TwoPlayerEloCalculator
{
// From the paper
const STABLE_KFACTOR = 24;
public function __construct()
{
parent::__construct(new KFactor(self::STABLE_KFACTOR));
}
public function getPlayerWinProbability(GameInfo $gameInfo, $playerRating, $opponentRating)
{
$ratingDifference = $playerRating - $opponentRating;
// See equation 1.1 in the TrueSkill paper
return GaussianDistribution::cumulativeTo(
$ratingDifference
/
(sqrt(2) * $gameInfo->getBeta()));
}
}
?>