More type work.

src/TrueSkill/Layers/PlayerPerformancesToTeamPerformancesLayer.php

@@ -6,10 +6,11 @@ use DNW\Skills\FactorGraphs\ScheduleStep;
 use DNW\Skills\FactorGraphs\ScheduleSequence;
 use DNW\Skills\PartialPlay;
 use DNW\Skills\TrueSkill\Factors\GaussianWeightedSumFactor;
+use DNW\Skills\FactorGraphs\Variable; 
 
 class PlayerPerformancesToTeamPerformancesLayer extends TrueSkillFactorGraphLayer
 {
-    public function buildLayer()
+    public function buildLayer(): void
     {
         $inputVariablesGroups = $this->getInputVariablesGroups();
         foreach ($inputVariablesGroups as $currentTeam) {
@@ -38,7 +39,7 @@ class PlayerPerformancesToTeamPerformancesLayer extends TrueSkillFactorGraphLaye
         );
     }
 
-    protected function createPlayerToTeamSumFactor($teamMembers, $sumVariable): GaussianWeightedSumFactor
+    protected function createPlayerToTeamSumFactor(array $teamMembers, Variable $sumVariable): GaussianWeightedSumFactor
     {
         $weights = array_map(
             function ($v) {
@@ -75,7 +76,7 @@ class PlayerPerformancesToTeamPerformancesLayer extends TrueSkillFactorGraphLaye
         return $this->scheduleSequence($allFactors, "all of the team's sum iterations");
     }
 
-    private function createOutputVariable($team)
+    private function createOutputVariable(array $team): Variable
     {
         $memberNames = array_map(fn ($currentPlayer) => (string) ($currentPlayer->getKey()), $team);
 

src/TrueSkill/Layers/PlayerPriorValuesToSkillsLayer.php

@@ -9,6 +9,7 @@ use DNW\Skills\Numerics\BasicMath;
 use DNW\Skills\Rating;
 use DNW\Skills\TrueSkill\Factors\GaussianPriorFactor;
 use DNW\Skills\TrueSkill\TrueSkillFactorGraph;
+use DNW\Skills\FactorGraphs\ScheduleSequence;
 
 // We intentionally have no Posterior schedule since the only purpose here is to
 // start the process.
@@ -19,7 +20,7 @@ class PlayerPriorValuesToSkillsLayer extends TrueSkillFactorGraphLayer
         parent::__construct($parentGraph);
     }
 
-    public function buildLayer()
+    public function buildLayer(): void
     {
         $teams = $this->teams;
         foreach ($teams as $currentTeam) {
@@ -41,7 +42,7 @@ class PlayerPriorValuesToSkillsLayer extends TrueSkillFactorGraphLayer
         }
     }
 
-    public function createPriorSchedule()
+    public function createPriorSchedule(): ScheduleSequence
     {
         $localFactors = $this->getLocalFactors();
 
@@ -54,7 +55,7 @@ class PlayerPriorValuesToSkillsLayer extends TrueSkillFactorGraphLayer
         );
     }
 
-    private function createPriorFactor(Rating $priorRating, Variable $skillsVariable)
+    private function createPriorFactor(Rating $priorRating, Variable $skillsVariable): GaussianPriorFactor
     {
         return new GaussianPriorFactor(
             $priorRating->getMean(),

src/TrueSkill/Layers/TeamPerformancesToTeamPerformanceDifferencesLayer.php

@@ -7,7 +7,7 @@ use DNW\Skills\TrueSkill\Factors\GaussianWeightedSumFactor;
 
 class TeamPerformancesToTeamPerformanceDifferencesLayer extends TrueSkillFactorGraphLayer
 {
-    public function buildLayer()
+    public function buildLayer(): void
     {
         $inputVariablesGroups = $this->getInputVariablesGroups();
         $inputVariablesGroupsCount = is_countable($inputVariablesGroups) ? count($inputVariablesGroups) : 0;
@@ -30,14 +30,14 @@ class TeamPerformancesToTeamPerformanceDifferencesLayer extends TrueSkillFactorG
         Variable $strongerTeam,
         Variable $weakerTeam,
         Variable $output
-    ) {
+    ): GaussianWeightedSumFactor {
         $teams = [$strongerTeam, $weakerTeam];
         $weights = [1.0, -1.0];
 
         return new GaussianWeightedSumFactor($output, $teams, $weights);
     }
 
-    private function createOutputVariable()
+    private function createOutputVariable(): Variable
     {
         return $this->getParentFactorGraph()->getVariableFactory()->createBasicVariable('Team performance difference');
     }