Start of factor graph port. Things don't work yet, but a lot of syntax updates towards PHP

PHPSkills/TrueSkill/Layers/PlayerSkillsToPerformancesLayer.php

@@ -0,0 +1,64 @@
+<?php
+
+namespace Moserware\Skills\TrueSkill\Layers;
+
+class PlayerSkillsToPerformancesLayer extends TrueSkillFactorGraphLayer
+{
+    public function __construct(TrueSkillFactorGraph $parentGraph)
+    {
+        parent::__construct($parentGraph);
+    }
+
+    public function buildLayer()
+    {
+        foreach ($this->getInputVariablesGroups() as $currentTeam)
+        {
+            $currentTeamPlayerPerformances = array();
+
+            foreach ($currentTeam as $playerSkillVariable)
+            {
+                $playerPerformance = $this->createOutputVariable($playerSkillVariable->getKey());
+                $this->addLayerFactor($this->createLikelihood($playerSkillVariable, $playerPerformance));
+                $currentTeamPlayerPerformances[] = $playerPerformance;
+            }
+
+            $this->getOutputVariablesGroups()[] = $currentTeamPlayerPerformances;
+        }
+    }
+
+    private function createLikelihood($playerSkill, $playerPerformance)
+    {
+        return new GaussianLikelihoodFactor(square($this->getParentFactorGraph()->getGameInfo()->getBeta()), $playerPerformance, $playerSkill);
+    }
+
+    private function createOutputVariable($key)
+    {
+        return $this->getParentFactorGraph()->getVariableFactory()->createKeyedVariable($key, "{0}'s performance", $key);
+    }
+
+    public function createPriorSchedule()
+    {
+        return $this->scheduleSequence(
+                array_map(
+                        function($likelihood)
+                        {
+                            return $this->scheduleStep("Skill to Perf step", $likelihood, 0);
+                        },
+                        $this->getLocalFactors()),
+                "All skill to performance sending");
+    }
+
+    public function createPosteriorSchedule()
+    {
+        return $this->scheduleSequence(
+                array_map(
+                        function($likelihood)
+                        {
+                            return new ScheduleStep("name", $likelihood, 1);                    
+                        },
+                        $this->getLocalFactors()),
+                "All skill to performance sending");
+    }
+}
+
+?>