trueskill/src/TrueSkill/Layers/PlayerPerformancesToTeamPerformancesLayer.php

<?php namespace Moserware\Skills\TrueSkill\Layers;

use Moserware\Skills\PartialPlay;
use Moserware\Skills\FactorGraphs\ScheduleLoop;
use Moserware\Skills\FactorGraphs\ScheduleSequence;
use Moserware\Skills\FactorGraphs\ScheduleStep;
use Moserware\Skills\TrueSkill\Factors\GaussianWeightedSumFactor;
use Moserware\Skills\TrueSkill\TrueSkillFactorGraph;

class PlayerPerformancesToTeamPerformancesLayer extends TrueSkillFactorGraphLayer
{
    public function __construct(TrueSkillFactorGraph &$parentGraph)
    {
        parent::__construct($parentGraph);
    }

    public function buildLayer()
    {
        $inputVariablesGroups = &$this->getInputVariablesGroups();
        foreach ($inputVariablesGroups as &$currentTeam) {
            $localCurrentTeam = &$currentTeam;
            $teamPerformance = &$this->createOutputVariable($localCurrentTeam);
            $newSumFactor = $this->createPlayerToTeamSumFactor($localCurrentTeam, $teamPerformance);

            $this->addLayerFactor($newSumFactor);

            // REVIEW: Does it make sense to have groups of one?
            $outputVariablesGroups = &$this->getOutputVariablesGroups();
            $outputVariablesGroups[] = array($teamPerformance);
        }
    }

    public function createPriorSchedule()
    {
        $localFactors = &$this->getLocalFactors();

        $sequence = &$this->scheduleSequence(
            array_map(
                function ($weightedSumFactor) {
                    return new ScheduleStep("Perf to Team Perf Step", $weightedSumFactor, 0);
                },
                $localFactors),
            "all player perf to team perf schedule");
        return $sequence;
    }

    protected function createPlayerToTeamSumFactor(&$teamMembers, &$sumVariable)
    {
        $weights = array_map(
            function ($v) {
                $player = &$v->getKey();
                return PartialPlay::getPartialPlayPercentage($player);
            },
            $teamMembers);

        return new GaussianWeightedSumFactor(
            $sumVariable,
            $teamMembers,
            $weights);

    }

    public function createPosteriorSchedule()
    {
        $allFactors = array();
        $localFactors = &$this->getLocalFactors();
        foreach ($localFactors as &$currentFactor) {
            $localCurrentFactor = &$currentFactor;
            $numberOfMessages = $localCurrentFactor->getNumberOfMessages();
            for ($currentIteration = 1; $currentIteration < $numberOfMessages; $currentIteration++) {
                $allFactors[] = new ScheduleStep("team sum perf @" . $currentIteration,
                    $localCurrentFactor, $currentIteration);
            }
        }
        return $this->scheduleSequence($allFactors, "all of the team's sum iterations");
    }

    private function &createOutputVariable(&$team)
    {
        $memberNames = \array_map(function ($currentPlayer) {
            return (string)($currentPlayer->getKey());
        },
            $team);

        $teamMemberNames = \join(", ", $memberNames);
        $outputVariable = &$this->getParentFactorGraph()->getVariableFactory()->createBasicVariable("Team[" . $teamMemberNames . "]'s performance");
        return $outputVariable;
    }
}