public function calculateNewRatings(GameInfo $gameInfo, array $teams, array $teamRanks)
{
// Basic argument checking
Guard::argumentNotNull($gameInfo, "gameInfo");
$this->validateTeamCountAndPlayersCountPerTeam($teams);
// Make sure things are in order
$teams = RankSorter::sort($teams, $teamRanks);
// Since we verified that each team has one player, we know the player is the first one
$winningTeamPlayers = $teams[0]->getAllPlayers();
$winner = $winningTeamPlayers[0];
$winnerPreviousRating = $teams[0]->getRating($winner);
$losingTeamPlayers = $teams[1]->getAllPlayers();
$loser = $losingTeamPlayers[0];
$loserPreviousRating = $teams[1]->getRating($loser);
$wasDraw = $teamRanks[0] == $teamRanks[1];
$results = new RatingContainer();
$results->setRating($winner, self::calculateNewRating($gameInfo, $winnerPreviousRating, $loserPreviousRating, $wasDraw ? PairwiseComparison::DRAW : PairwiseComparison::WIN));
$results->setRating($loser, self::calculateNewRating($gameInfo, $loserPreviousRating, $winnerPreviousRating, $wasDraw ? PairwiseComparison::DRAW : PairwiseComparison::LOSE));
// And we're done!
return $results;
}
public function getUpdatedRatings()
{
$result = new RatingContainer();
$priorLayerOutputVariablesGroups =& $this->_priorLayer->getOutputVariablesGroups();
foreach ($priorLayerOutputVariablesGroups as &$currentTeam) {
foreach ($currentTeam as &$currentPlayer) {
$localCurrentPlayer =& $currentPlayer->getKey();
$newRating = new Rating($currentPlayer->getValue()->getMean(), $currentPlayer->getValue()->getStandardDeviation());
$result->setRating($localCurrentPlayer, $newRating);
}
}
return $result;
}
private static function updatePlayerRatings(GameInfo $gameInfo, RatingContainer &$newPlayerRatings, Team $selfTeam, Team $otherTeam, $selfToOtherTeamComparison)
{
$drawMargin = DrawMargin::getDrawMarginFromDrawProbability($gameInfo->getDrawProbability(), $gameInfo->getBeta());
$betaSquared = square($gameInfo->getBeta());
$tauSquared = square($gameInfo->getDynamicsFactor());
$totalPlayers = $selfTeam->count() + $otherTeam->count();
$meanGetter = function ($currentRating) {
return $currentRating->getMean();
};
$selfMeanSum = sum($selfTeam->getAllRatings(), $meanGetter);
$otherTeamMeanSum = sum($otherTeam->getAllRatings(), $meanGetter);
$varianceGetter = function ($currentRating) {
return square($currentRating->getStandardDeviation());
};
$c = sqrt(sum($selfTeam->getAllRatings(), $varianceGetter) + sum($otherTeam->getAllRatings(), $varianceGetter) + $totalPlayers * $betaSquared);
$winningMean = $selfMeanSum;
$losingMean = $otherTeamMeanSum;
switch ($selfToOtherTeamComparison) {
case PairwiseComparison::WIN:
case PairwiseComparison::DRAW:
// NOP
break;
case PairwiseComparison::LOSE:
$winningMean = $otherTeamMeanSum;
$losingMean = $selfMeanSum;
break;
}
$meanDelta = $winningMean - $losingMean;
if ($selfToOtherTeamComparison != PairwiseComparison::DRAW) {
// non-draw case
$v = TruncatedGaussianCorrectionFunctions::vExceedsMarginScaled($meanDelta, $drawMargin, $c);
$w = TruncatedGaussianCorrectionFunctions::wExceedsMarginScaled($meanDelta, $drawMargin, $c);
$rankMultiplier = (int) $selfToOtherTeamComparison;
} else {
// assume draw
$v = TruncatedGaussianCorrectionFunctions::vWithinMarginScaled($meanDelta, $drawMargin, $c);
$w = TruncatedGaussianCorrectionFunctions::wWithinMarginScaled($meanDelta, $drawMargin, $c);
$rankMultiplier = 1;
}
$selfTeamAllPlayers =& $selfTeam->getAllPlayers();
foreach ($selfTeamAllPlayers as &$selfTeamCurrentPlayer) {
$localSelfTeamCurrentPlayer =& $selfTeamCurrentPlayer;
$previousPlayerRating = $selfTeam->getRating($localSelfTeamCurrentPlayer);
$meanMultiplier = (square($previousPlayerRating->getStandardDeviation()) + $tauSquared) / $c;
$stdDevMultiplier = (square($previousPlayerRating->getStandardDeviation()) + $tauSquared) / square($c);
$playerMeanDelta = $rankMultiplier * $meanMultiplier * $v;
$newMean = $previousPlayerRating->getMean() + $playerMeanDelta;
$newStdDev = sqrt((square($previousPlayerRating->getStandardDeviation()) + $tauSquared) * (1 - $w * $stdDevMultiplier));
$newPlayerRatings->setRating($localSelfTeamCurrentPlayer, new Rating($newMean, $newStdDev));
}
}