Much stricter coding standards for phpstan, phpstan and psalm.

.woodpecker.yml

@@ -1,17 +0,0 @@
-when:
-  - event: [push, tag]
-steps:
-  - name: requirements
-    image: composer
-    commands:
-    - composer install --no-dev
-  - name: run
-    image: php:cli-bookworm
-    commands:
-      - php examples/3teams.php
-      - php examples/basic.php
-  - name: test
-    image: composer
-    commands:
-    - composer install
-    - vendor/bin/phpunit tests --no-coverage

benchmark/BasicBench.php

@@ -14,7 +14,7 @@ use DNW\Skills\Team;
 /**
  * Basic Benchmarks.
  */
-class BasicBench
+final class BasicBench
 {
     /**
      * To benchmark performance when using TwoPlayerTrueSkillCalculator

src/FactorGraphs/FactorList.php

@@ -7,7 +7,7 @@ namespace DNW\Skills\FactorGraphs;
 /**
  * Helper class for computing the factor graph's normalization constant.
  */
-class FactorList
+final class FactorList
 {
     /**
      * @var Factor[] $list
@@ -31,11 +31,11 @@ class FactorList
             $numberOfMessages = $factor->getNumberOfMessages();
 
             for ($j = 0; $j < $numberOfMessages; ++$j) {
-                $sumLogZ += $factor->sendMessageIndex($j);
+                $sumLogZ += (float)$factor->sendMessageIndex($j);
             }
         }
 
-        $sumLogS = 0;
+        $sumLogS = 0.0;
 
         foreach ($list as &$currentFactor) {
             $sumLogS += $currentFactor->getLogNormalization();

src/FactorGraphs/KeyedVariable.php

@@ -4,7 +4,7 @@ declare(strict_types=1);
 
 namespace DNW\Skills\FactorGraphs;
 
-class KeyedVariable extends Variable
+final class KeyedVariable extends Variable
 {
     public function __construct(private readonly mixed $key, mixed $prior)
     {

src/FactorGraphs/Message.php

@@ -6,7 +6,7 @@ namespace DNW\Skills\FactorGraphs;
 
 use DNW\Skills\Numerics\GaussianDistribution;
 
-class Message
+final class Message
 {
     public function __construct(private GaussianDistribution $value)
     {

src/FactorGraphs/ScheduleLoop.php

@@ -4,7 +4,7 @@ declare(strict_types=1);
 
 namespace DNW\Skills\FactorGraphs;
 
-class ScheduleLoop extends Schedule
+final class ScheduleLoop extends Schedule
 {
     public function __construct(private readonly Schedule $scheduleToLoop, private readonly float $maxDelta)
     {

src/FactorGraphs/ScheduleSequence.php

@@ -4,7 +4,7 @@ declare(strict_types=1);
 
 namespace DNW\Skills\FactorGraphs;
 
-class ScheduleSequence extends Schedule
+final class ScheduleSequence extends Schedule
 {
     /**
      * @param Schedule[] $schedules

src/FactorGraphs/ScheduleStep.php

@@ -4,7 +4,7 @@ declare(strict_types=1);
 
 namespace DNW\Skills\FactorGraphs;
 
-class ScheduleStep extends Schedule
+final class ScheduleStep extends Schedule
 {
     public function __construct(private readonly Factor $factor, private readonly int $index)
     {

src/FactorGraphs/VariableFactory.php

@@ -4,9 +4,9 @@ declare(strict_types=1);
 
 namespace DNW\Skills\FactorGraphs;
 
-class VariableFactory
+final readonly class VariableFactory
 {
-    public function __construct(private readonly \Closure $varPriorInitializer)
+    public function __construct(private \Closure $varPriorInitializer)
     {
     }
 

src/GameInfo.php

@@ -7,7 +7,7 @@ namespace DNW\Skills;
 /**
  * Parameters about the game for calculating the TrueSkill.
  */
-class GameInfo
+final readonly class GameInfo
 {
     /**
      * Default initial mean / 6
@@ -26,11 +26,11 @@ class GameInfo
     private const float DEFAULT_INITIAL_STANDARD_DEVIATION = 8.3333333333333333333333333333333;
 
     public function __construct(
-        private readonly float $initialMean = self::DEFAULT_INITIAL_MEAN,
-        private readonly float $initialStdDev = self::DEFAULT_INITIAL_STANDARD_DEVIATION,
-        private readonly float $beta = self::DEFAULT_BETA,
-        private readonly float $dynamicsFactor = self::DEFAULT_DYNAMICS_FACTOR,
-        private readonly float $drawProbability = self::DEFAULT_DRAW_PROBABILITY
+        private float $initialMean = self::DEFAULT_INITIAL_MEAN,
+        private float $initialStdDev = self::DEFAULT_INITIAL_STANDARD_DEVIATION,
+        private float $beta = self::DEFAULT_BETA,
+        private float $dynamicsFactor = self::DEFAULT_DYNAMICS_FACTOR,
+        private float $drawProbability = self::DEFAULT_DRAW_PROBABILITY
     )
     {
     }

src/Guard.php

@@ -11,7 +11,7 @@ use Exception;
  *
  * @see http://www.moserware.com/2008/01/borrowing-ideas-from-3-interesting.html
  */
-class Guard
+final class Guard
 {
     public static function argumentIsValidIndex(int $index, int $count, string $parameterName): void
     {
@@ -23,7 +23,7 @@ class Guard
     public static function argumentInRangeInclusive(float $value, float $min, float $max, string $parameterName): void
     {
         if (($value < $min) || ($value > $max)) {
-            throw new Exception($parameterName . ' is not in the valid range [' . $min . ', ' . $max . ']');
+            throw new Exception($parameterName . ' is not in the valid range [' . (int)$min . ', ' . (int)$max . ']');
         }
     }
 }

src/HashMap.php

@@ -7,7 +7,7 @@ namespace DNW\Skills;
 /**
  * Basic hashmap that supports object keys.
  */
-class HashMap
+final class HashMap
 {
     /**
      * @var mixed[] $hashToValue

src/Numerics/BasicMath.php

@@ -10,7 +10,7 @@ namespace DNW\Skills\Numerics;
  * @author    Jeff Moser <jeff@moserware.com>
  * @copyright 2010 Jeff Moser
  */
-class BasicMath
+final class BasicMath
 {
     /**
      * Squares the input (input^2 = input * input)

src/Numerics/GaussianDistribution.php

@@ -10,7 +10,7 @@ namespace DNW\Skills\Numerics;
  * @author    Jeff Moser <jeff@moserware.com>
  * @copyright 2010 Jeff Moser
  */
-class GaussianDistribution
+final class GaussianDistribution
 {
     private const float DEFAULT_STANDARD_DEVIATION = 1.0;
 
@@ -171,7 +171,7 @@ class GaussianDistribution
         $meanDifference = $numerator->mean - $denominator->mean;
 
         return log($denominator->variance) + self::M_LOG_SQRT_2_PI - log($varianceDifference) / 2.0 +
-        BasicMath::square($meanDifference) / (2 * $varianceDifference);
+        BasicMath::square($meanDifference) / (2.0 * $varianceDifference);
     }
 
     public static function at(float $var, float $mean = 0.0, float $standardDeviation = 1.0): float
@@ -182,7 +182,7 @@ class GaussianDistribution
         //        stdDev * sqrt(2*pi)
 
         $multiplier = 1.0 / ($standardDeviation * self::M_SQRT_2_PI);
-        $expPart = exp((-1.0 * BasicMath::square($var - $mean)) / (2 * BasicMath::square($standardDeviation)));
+        $expPart = exp((-1.0 * BasicMath::square($var - $mean)) / (2.0 * BasicMath::square($standardDeviation)));
 
         return $multiplier * $expPart;
     }
@@ -200,7 +200,7 @@ class GaussianDistribution
         $z = abs($var);
 
         $t = 2.0 / (2.0 + $z);
-        $ty = 4 * $t - 2;
+        $ty = 4.0 * $t - 2.0;
 
         $coefficients = [
             -1.3026537197817094,
@@ -259,8 +259,8 @@ class GaussianDistribution
             return 100;
         }
 
-        $pp = ($p < 1.0) ? $p : 2 - $p;
-        $t = sqrt(-2 * log($pp / 2.0)); // Initial guess
+        $pp = ($p < 1.0) ? $p : 2.0 - $p;
+        $t = sqrt(-2.0 * log($pp / 2.0)); // Initial guess
         $x = -M_SQRT1_2 * ((2.30753 + $t * 0.27061) / (1.0 + $t * (0.99229 + $t * 0.04481)) - $t);
 
         for ($j = 0; $j < 2; ++$j) {
@@ -274,6 +274,6 @@ class GaussianDistribution
     public static function inverseCumulativeTo(float $var, float $mean = 0.0, float $standardDeviation = 1.0): float
     {
         // From numerical recipes, page 320
-        return $mean - M_SQRT2 * $standardDeviation * GaussianDistribution::inverseErrorFunctionCumulativeTo(2 * $var);
+        return $mean - M_SQRT2 * $standardDeviation * GaussianDistribution::inverseErrorFunctionCumulativeTo(2.0 * $var);
     }
 }

src/Numerics/IdentityMatrix.php

@@ -4,7 +4,7 @@ declare(strict_types=1);
 
 namespace DNW\Skills\Numerics;
 
-class IdentityMatrix extends DiagonalMatrix
+final class IdentityMatrix extends DiagonalMatrix
 {
     public function __construct(int $rows)
     {

src/Numerics/Matrix.php

@@ -130,10 +130,10 @@ class Matrix
             // | a b |
             // | c d |
             // The determinant is ad - bc
-            $a = $this->getValue(0, 0);
-            $b = $this->getValue(0, 1);
-            $c = $this->getValue(1, 0);
-            $d = $this->getValue(1, 1);
+            $a = (float)$this->getValue(0, 0);
+            $b = (float)$this->getValue(0, 1);
+            $c = (float)$this->getValue(1, 0);
+            $d = (float)$this->getValue(1, 1);
 
             return $a * $d - $b * $c;
         }
@@ -148,7 +148,7 @@ class Matrix
 
         // I expand along the first row
         for ($currentColumn = 0; $currentColumn < $this->columnCount; ++$currentColumn) {
-            $firstRowColValue = $this->getValue(0, $currentColumn);
+            $firstRowColValue = (float)$this->getValue(0, $currentColumn);
             $cofactor = $this->getCofactor(0, $currentColumn);
             $itemToAdd = $firstRowColValue * $cofactor;
             $result += $itemToAdd;
@@ -201,7 +201,7 @@ class Matrix
     public function getInverse(): Matrix|SquareMatrix
     {
         if (($this->rowCount == 1) && ($this->columnCount == 1)) {
-            return new SquareMatrix(1.0 / $this->getValue(0, 0));
+            return new SquareMatrix(1.0 / (float)$this->getValue(0, 0));
         }
 
         // Take the simple approach:
@@ -240,9 +240,9 @@ class Matrix
         for ($currentRow = 0; $currentRow < $left->getRowCount(); ++$currentRow) {
             for ($currentColumn = 0; $currentColumn < $right->getColumnCount(); ++$currentColumn) {
                 $resultMatrix[$currentRow][$currentColumn] =
-                    $left->getValue($currentRow, $currentColumn)
+                    (float)$left->getValue($currentRow, $currentColumn)
                     +
-                    $right->getValue($currentRow, $currentColumn);
+                    (float)$right->getValue($currentRow, $currentColumn);
             }
         }
 
@@ -268,8 +268,8 @@ class Matrix
                 $productValue = 0;
 
                 for ($vectorIndex = 0; $vectorIndex < $left->getColumnCount(); ++$vectorIndex) {
-                    $leftValue = $left->getValue($currentRow, $vectorIndex);
-                    $rightValue = $right->getValue($vectorIndex, $currentColumn);
+                    $leftValue = (float)$left->getValue($currentRow, $vectorIndex);
+                    $rightValue = (float)$right->getValue($vectorIndex, $currentColumn);
                     $vectorIndexProduct = $leftValue * $rightValue;
                     $productValue += $vectorIndexProduct;
                 }
@@ -339,8 +339,8 @@ class Matrix
             for ($currentColumn = 0; $currentColumn < $this->columnCount; ++$currentColumn) {
                 $delta =
                     abs(
-                        $this->getValue($currentRow, $currentColumn) -
-                        $otherMatrix->getValue($currentRow, $currentColumn)
+                        (float)$this->getValue($currentRow, $currentColumn) -
+                        (float)$otherMatrix->getValue($currentRow, $currentColumn)
                     );
 
                 if ($delta > self::ERROR_TOLERANCE) {

src/Numerics/SquareMatrix.php

@@ -4,7 +4,7 @@ declare(strict_types=1);
 
 namespace DNW\Skills\Numerics;
 
-class SquareMatrix extends Matrix
+final class SquareMatrix extends Matrix
 {
     public function __construct(float|int ...$allValues)
     {

src/Numerics/Vector.php

@@ -4,7 +4,7 @@ declare(strict_types=1);
 
 namespace DNW\Skills\Numerics;
 
-class Vector extends Matrix
+final class Vector extends Matrix
 {
     /**
      * @param float[] $vectorValues

src/PartialPlay.php

@@ -4,7 +4,7 @@ declare(strict_types=1);
 
 namespace DNW\Skills;
 
-class PartialPlay
+final class PartialPlay
 {
     public static function getPartialPlayPercentage(Player $player): float
     {

src/Player.php

@@ -7,15 +7,15 @@ namespace DNW\Skills;
 /**
  * Represents a player who has a Rating.
  */
-class Player implements ISupportPartialPlay, ISupportPartialUpdate
+final readonly class Player implements ISupportPartialPlay, ISupportPartialUpdate
 {
     private const float DEFAULT_PARTIAL_PLAY_PERCENTAGE = 1.0; // = 100% play time
 
     private const float DEFAULT_PARTIAL_UPDATE_PERCENTAGE = 1.0;
 
-    private readonly float $PartialPlayPct;
+    private float $PartialPlayPct;
 
-    private readonly float $PartialUpdatePct;
+    private float $PartialUpdatePct;
 
     /**
      * Constructs a player.
@@ -25,7 +25,7 @@ class Player implements ISupportPartialPlay, ISupportPartialUpdate
      * @param float $partialUpdatePct Indicated how much of a skill update a player should receive where 0 represents no update and 1.0 represents 100% of the update.
      */
     public function __construct(
-        private readonly mixed $Id,
+        private mixed $Id,
         float $partialPlayPct = self::DEFAULT_PARTIAL_PLAY_PERCENTAGE,
         float $partialUpdatePct = self::DEFAULT_PARTIAL_UPDATE_PERCENTAGE
     )

src/PlayersRange.php

@@ -6,6 +6,6 @@ namespace DNW\Skills;
 
 use DNW\Skills\Numerics\Range;
 
-class PlayersRange extends Range
+final class PlayersRange extends Range
 {
 }

src/RankSorter.php

@@ -7,7 +7,7 @@ namespace DNW\Skills;
 /**
  * Helper class to sort ranks in non-decreasing order.
  */
-class RankSorter
+final class RankSorter
 {
     /**
      * Performs an in-place sort of the items in according to the ranks in non-decreasing order.

src/Rating.php

@@ -9,7 +9,7 @@ use DNW\Skills\Numerics\GaussianDistribution;
 /**
  * Container for a player's rating.
  */
-class Rating
+final readonly class Rating
 {
     private const float CONSERVATIVE_STANDARD_DEVIATION_MULTIPLIER = 3;
 
@@ -18,9 +18,9 @@ class Rating
      *
      * @param float     $mean                                    The statistical mean value of the rating (also known as mu).
      * @param float     $standardDeviation                       The standard deviation of the rating (also known as s).
-     * @param float|int $conservativeStandardDeviationMultiplier optional The number of standardDeviations to subtract from the mean to achieve a conservative rating.
+     * @param float     $conservativeStandardDeviationMultiplier optional The number of standardDeviations to subtract from the mean to achieve a conservative rating.
      */
-    public function __construct(private readonly float $mean, private readonly float $standardDeviation, private readonly float|int $conservativeStandardDeviationMultiplier = self::CONSERVATIVE_STANDARD_DEVIATION_MULTIPLIER)
+    public function __construct(private float $mean, private float $standardDeviation, private float $conservativeStandardDeviationMultiplier = self::CONSERVATIVE_STANDARD_DEVIATION_MULTIPLIER)
     {
     }
 

src/Team.php

@@ -4,7 +4,7 @@ declare(strict_types=1);
 
 namespace DNW\Skills;
 
-class Team extends RatingContainer
+final class Team extends RatingContainer
 {
     public function __construct(?Player $player = NULL, ?Rating $rating = NULL)
     {

src/TeamsRange.php

@@ -6,6 +6,6 @@ namespace DNW\Skills;
 
 use DNW\Skills\Numerics\Range;
 
-class TeamsRange extends Range
+final class TeamsRange extends Range
 {
 }

src/TrueSkill/DrawMargin.php

@@ -18,6 +18,6 @@ final class DrawMargin
         //
         // margin = inversecdf((draw probability + 1)/2) * sqrt(n1+n2) * beta
         // n1 and n2 are the number of players on each team
-        return GaussianDistribution::inverseCumulativeTo(.5 * ($drawProbability + 1), 0, 1) * M_SQRT2 * $beta;
+        return GaussianDistribution::inverseCumulativeTo(0.5 * ($drawProbability + 1.0), 0.0, 1.0) * M_SQRT2 * $beta;
     }
 }

src/TrueSkill/FactorGraphTrueSkillCalculator.php

@@ -22,7 +22,7 @@ use DNW\Skills\Rating;
 /**
  * Calculates TrueSkill using a full factor graph.
  */
-class FactorGraphTrueSkillCalculator extends SkillCalculator
+final class FactorGraphTrueSkillCalculator extends SkillCalculator
 {
     public function __construct()
     {

src/TrueSkill/Factors/GaussianGreaterThanFactor.php

@@ -14,7 +14,7 @@ use DNW\Skills\TrueSkill\TruncatedGaussianCorrectionFunctions;
  *
  * See the accompanying math paper for more details.
  */
-class GaussianGreaterThanFactor extends GaussianFactor
+final class GaussianGreaterThanFactor extends GaussianFactor
 {
     public function __construct(private readonly float $epsilon, Variable $variable)
     {

src/TrueSkill/Factors/GaussianLikelihoodFactor.php

@@ -15,7 +15,7 @@ use Exception;
  *
  * See the accompanying math paper for more details.
  */
-class GaussianLikelihoodFactor extends GaussianFactor
+final class GaussianLikelihoodFactor extends GaussianFactor
 {
     private readonly float $precision;
 

src/TrueSkill/Factors/GaussianPriorFactor.php

@@ -13,7 +13,7 @@ use DNW\Skills\Numerics\GaussianDistribution;
  *
  * See the accompanying math paper for more details.
  */
-class GaussianPriorFactor extends GaussianFactor
+final class GaussianPriorFactor extends GaussianFactor
 {
     private readonly GaussianDistribution $newMessage;
 

src/TrueSkill/Factors/GaussianWeightedSumFactor.php

@@ -16,7 +16,7 @@ use DNW\Skills\Numerics\GaussianDistribution;
  *
  * See the accompanying math paper for more details.
  */
-class GaussianWeightedSumFactor extends GaussianFactor
+final class GaussianWeightedSumFactor extends GaussianFactor
 {
     /**
      * @var array<int[]> $varIndexOrdersForWeights

src/TrueSkill/Factors/GaussianWithinFactor.php

@@ -14,7 +14,7 @@ use DNW\Skills\TrueSkill\TruncatedGaussianCorrectionFunctions;
  *
  * See the accompanying math paper for more details.
  */
-class GaussianWithinFactor extends GaussianFactor
+final class GaussianWithinFactor extends GaussianFactor
 {
     public function __construct(private readonly float $epsilon, Variable $variable)
     {

src/TrueSkill/Layers/IteratedTeamDifferencesInnerLayer.php

@@ -11,7 +11,7 @@ use DNW\Skills\TrueSkill\TrueSkillFactorGraph;
 use Exception;
 
 // The whole purpose of this is to do a loop on the bottom
-class IteratedTeamDifferencesInnerLayer extends TrueSkillFactorGraphLayer
+final class IteratedTeamDifferencesInnerLayer extends TrueSkillFactorGraphLayer
 {
     public function __construct(
         TrueSkillFactorGraph $parentGraph,

src/TrueSkill/Layers/PlayerPerformancesToTeamPerformancesLayer.php

@@ -11,7 +11,7 @@ use DNW\Skills\TrueSkill\Factors\GaussianWeightedSumFactor;
 use DNW\Skills\FactorGraphs\Variable;
 use DNW\Skills\FactorGraphs\KeyedVariable;
 
-class PlayerPerformancesToTeamPerformancesLayer extends TrueSkillFactorGraphLayer
+final class PlayerPerformancesToTeamPerformancesLayer extends TrueSkillFactorGraphLayer
 {
     #[\Override]
     public function buildLayer(): void
@@ -51,7 +51,7 @@ class PlayerPerformancesToTeamPerformancesLayer extends TrueSkillFactorGraphLaye
     /**
      * @param KeyedVariable[] $teamMembers
      */
-    protected function createPlayerToTeamSumFactor(array $teamMembers, Variable $sumVariable): GaussianWeightedSumFactor
+    private function createPlayerToTeamSumFactor(array $teamMembers, Variable $sumVariable): GaussianWeightedSumFactor
     {
         $weights = array_map(
             static function ($v): float {

src/TrueSkill/Layers/PlayerPriorValuesToSkillsLayer.php

@@ -17,7 +17,7 @@ use DNW\Skills\FactorGraphs\ScheduleSequence;
 
 // We intentionally have no Posterior schedule since the only purpose here is to
 // start the process.
-class PlayerPriorValuesToSkillsLayer extends TrueSkillFactorGraphLayer
+final class PlayerPriorValuesToSkillsLayer extends TrueSkillFactorGraphLayer
 {
     /**
      * @param Team[] $teams

src/TrueSkill/Layers/PlayerSkillsToPerformancesLayer.php

@@ -11,7 +11,7 @@ use DNW\Skills\Numerics\BasicMath;
 use DNW\Skills\TrueSkill\Factors\GaussianLikelihoodFactor;
 use DNW\Skills\FactorGraphs\ScheduleSequence;
 
-class PlayerSkillsToPerformancesLayer extends TrueSkillFactorGraphLayer
+final class PlayerSkillsToPerformancesLayer extends TrueSkillFactorGraphLayer
 {
     #[\Override]
     public function buildLayer(): void

src/TrueSkill/Layers/TeamDifferencesComparisonLayer.php

@@ -9,7 +9,7 @@ use DNW\Skills\TrueSkill\Factors\GaussianGreaterThanFactor;
 use DNW\Skills\TrueSkill\Factors\GaussianWithinFactor;
 use DNW\Skills\TrueSkill\TrueSkillFactorGraph;
 
-class TeamDifferencesComparisonLayer extends TrueSkillFactorGraphLayer
+final class TeamDifferencesComparisonLayer extends TrueSkillFactorGraphLayer
 {
     private readonly float $epsilon;
 

src/TrueSkill/Layers/TeamPerformancesToTeamPerformanceDifferencesLayer.php

@@ -7,7 +7,7 @@ namespace DNW\Skills\TrueSkill\Layers;
 use DNW\Skills\FactorGraphs\Variable;
 use DNW\Skills\TrueSkill\Factors\GaussianWeightedSumFactor;
 
-class TeamPerformancesToTeamPerformanceDifferencesLayer extends TrueSkillFactorGraphLayer
+final class TeamPerformancesToTeamPerformanceDifferencesLayer extends TrueSkillFactorGraphLayer
 {
     #[\Override]
     public function buildLayer(): void

src/TrueSkill/TrueSkillFactorGraph.php

@@ -23,7 +23,7 @@ use DNW\Skills\TrueSkill\Layers\PlayerSkillsToPerformancesLayer;
 use DNW\Skills\TrueSkill\Layers\TeamDifferencesComparisonLayer;
 use DNW\Skills\TrueSkill\Layers\TeamPerformancesToTeamPerformanceDifferencesLayer;
 
-class TrueSkillFactorGraph extends FactorGraph
+final class TrueSkillFactorGraph extends FactorGraph
 {
     /**
      * @var FactorGraphLayer[] $layers

src/TrueSkill/TruncatedGaussianCorrectionFunctions.php

@@ -6,7 +6,7 @@ namespace DNW\Skills\TrueSkill;
 
 use DNW\Skills\Numerics\GaussianDistribution;
 
-class TruncatedGaussianCorrectionFunctions
+final class TruncatedGaussianCorrectionFunctions
 {
     // These functions from the bottom of page 4 of the TrueSkill paper.
 

src/TrueSkill/TwoPlayerTrueSkillCalculator.php

@@ -21,7 +21,7 @@ use DNW\Skills\TeamsRange;
  * When you only have two players, a lot of the math simplifies. The main purpose of this class
  * is to show the bare minimum of what a TrueSkill implementation should have.
  */
-class TwoPlayerTrueSkillCalculator extends SkillCalculator
+final class TwoPlayerTrueSkillCalculator extends SkillCalculator
 {
     public function __construct()
     {
@@ -95,7 +95,7 @@ class TwoPlayerTrueSkillCalculator extends SkillCalculator
             +
             BasicMath::square($opponentRating->getStandardDeviation())
             +
-            2 * BasicMath::square($gameInfo->getBeta())
+            2.0 * BasicMath::square($gameInfo->getBeta())
         );
 
         $winningMean = $selfRating->getMean();
@@ -131,7 +131,7 @@ class TwoPlayerTrueSkillCalculator extends SkillCalculator
         $stdDevMultiplier = $varianceWithDynamics / BasicMath::square($c);
 
         $newMean = $selfRating->getMean() + ($rankMultiplier * $meanMultiplier * $v);
-        $newStdDev = sqrt($varianceWithDynamics * (1 - $w * $stdDevMultiplier));
+        $newStdDev = sqrt($varianceWithDynamics * (1.0 - $w * $stdDevMultiplier));
 
         return new Rating($newMean, $newStdDev);
     }
@@ -160,16 +160,16 @@ class TwoPlayerTrueSkillCalculator extends SkillCalculator
 
         // This is the square root part of the equation:
         $sqrtPart = sqrt(
-            (2 * $betaSquared)
+            (2.0 * $betaSquared)
             /
-            (2 * $betaSquared + $player1SigmaSquared + $player2SigmaSquared)
+            (2.0 * $betaSquared + $player1SigmaSquared + $player2SigmaSquared)
         );
 
         // This is the exponent part of the equation:
         $expPart = exp(
-            (-1 * BasicMath::square($player1Rating->getMean() - $player2Rating->getMean()))
+            (-1.0 * BasicMath::square($player1Rating->getMean() - $player2Rating->getMean()))
             /
-            (2 * (2 * $betaSquared + $player1SigmaSquared + $player2SigmaSquared))
+            (2.0 * (2.0 * $betaSquared + $player1SigmaSquared + $player2SigmaSquared))
         );
 
         return $sqrtPart * $expPart;

src/TrueSkill/TwoTeamTrueSkillCalculator.php

@@ -21,7 +21,7 @@ use DNW\Skills\TeamsRange;
  *
  * When you only have two teams, the math is still simple: no factor graphs are used yet.
  */
-class TwoTeamTrueSkillCalculator extends SkillCalculator
+final class TwoTeamTrueSkillCalculator extends SkillCalculator
 {
     public function __construct()
     {
@@ -122,7 +122,7 @@ class TwoTeamTrueSkillCalculator extends SkillCalculator
             // assume draw
             $v = TruncatedGaussianCorrectionFunctions::vWithinMarginScaled($meanDelta, $drawMargin, $c);
             $w = TruncatedGaussianCorrectionFunctions::wWithinMarginScaled($meanDelta, $drawMargin, $c);
-            $rankMultiplier = 1;
+            $rankMultiplier = 1.0;
         }
 
         $selfTeamAllPlayers = $selfTeam->getAllPlayers();
@@ -137,7 +137,7 @@ class TwoTeamTrueSkillCalculator extends SkillCalculator
             $newMean = $previousPlayerRating->getMean() + $playerMeanDelta;
 
             $newStdDev = sqrt(
-                (BasicMath::square($previousPlayerRating->getStandardDeviation()) + $tauSquared) * (1 - $w * $stdDevMultiplier)
+                (BasicMath::square($previousPlayerRating->getStandardDeviation()) + $tauSquared) * (1.0 - $w * $stdDevMultiplier)
             );
 
             $newPlayerRatings->setRating($localSelfTeamCurPlayer, new Rating($newMean, $newStdDev));
@@ -184,9 +184,9 @@ class TwoTeamTrueSkillCalculator extends SkillCalculator
         );
 
         $expPart = exp(
-            (-1 * BasicMath::square($team1MeanSum - $team2MeanSum))
+            (-1.0 * BasicMath::square($team1MeanSum - $team2MeanSum))
             /
-            (2 * ($totalPlayers * $betaSquared + $team1StdDevSquared + $team2StdDevSquared))
+            (2.0 * ($totalPlayers * $betaSquared + $team1StdDevSquared + $team2StdDevSquared))
         );
 
         return $expPart * $sqrtPart;

tests/FactorGraphs/VariableTest.php

@@ -12,7 +12,7 @@ use PHPUnit\Framework\Attributes\UsesClass;
 
 #[CoversClass(Variable::class)]
 #[UsesClass(GaussianDistribution::class)]
-class VariableTest extends TestCase
+final class VariableTest extends TestCase
 {
     public function testGetterSetter(): void
     {

tests/GameInfoTest.php

@@ -12,7 +12,7 @@ use PHPUnit\Framework\Attributes\UsesClass;
 
 #[CoversClass(GameInfo::class)]
 #[UsesClass(Rating::class)]
-class GameInfoTest extends TestCase
+final class GameInfoTest extends TestCase
 {
     public function testMembers(): void
     {

tests/GuardTest.php

@@ -10,7 +10,7 @@ use PHPUnit\Framework\TestCase;
 use PHPUnit\Framework\Attributes\CoversClass;
 
 #[CoversClass(Guard::class)]
-class GuardTest extends TestCase
+final class GuardTest extends TestCase
 {
     public function testargumentIsValidIndexArgumentAbove(): void
     {

tests/HashMapTest.php

@@ -10,7 +10,7 @@ use PHPUnit\Framework\Attributes\CoversClass;
 use stdClass;
 
 #[CoversClass(HashMap::class)]
-class HashMapTest extends TestCase
+final class HashMapTest extends TestCase
 {
     public function testHashmap(): void
     {

tests/Numerics/BasicMathTest.php

@@ -9,7 +9,7 @@ use PHPUnit\Framework\TestCase;
 use PHPUnit\Framework\Attributes\CoversClass;
 
 #[CoversClass(BasicMath::class)]
-class BasicMathTest extends TestCase
+final class BasicMathTest extends TestCase
 {
     public function testSquare(): void
     {
@@ -23,7 +23,7 @@ class BasicMathTest extends TestCase
         $arr = [1, 1, 1, 1];
 
         $func_return = static fn(float $f): float => $f;
-        $func_double = static fn(float $f): float => $f * 2;
+        $func_double = static fn(float $f): float => $f * 2.0;
         $this->assertEquals(4, BasicMath::sum($arr, $func_return));
         $this->assertEquals(8, BasicMath::sum($arr, $func_double));
     }

tests/Numerics/GaussianDistributionTest.php

@@ -12,7 +12,7 @@ use PHPUnit\Framework\Attributes\UsesClass;
 
 #[CoversClass(GaussianDistribution::class)]
 #[UsesClass(BasicMath::class)]
-class GaussianDistributionTest extends TestCase
+final class GaussianDistributionTest extends TestCase
 {
     private const float ERROR_TOLERANCE = 0.000001;
 
@@ -24,7 +24,7 @@ class GaussianDistributionTest extends TestCase
         $this->assertEquals(9, $gd->getVariance());
         $this->assertEquals(3, $gd->getStandardDeviation());
         $this->assertEquals(1 / 9, $gd->getPrecision());
-        $this->assertEquals(1 / 9 * 10, $gd->getPrecisionMean());
+        $this->assertEquals(1.0 / 9.0 * 10.0, $gd->getPrecisionMean());
         $this->assertEqualsWithDelta(0.13298076013, $gd->getNormalizationConstant(), GaussianDistributionTest::ERROR_TOLERANCE);
     }
 
@@ -57,7 +57,7 @@ class GaussianDistributionTest extends TestCase
 
         $product2 = GaussianDistribution::multiply($m4s5, $m6s7);
 
-        $expectedMean = (4 * BasicMath::square(7) + 6 * BasicMath::square(5)) / (BasicMath::square(5) + BasicMath::square(7));
+        $expectedMean = (4.0 * BasicMath::square(7) + 6.0 * BasicMath::square(5)) / (BasicMath::square(5) + BasicMath::square(7));
         $this->assertEqualsWithDelta($expectedMean, $product2->getMean(), GaussianDistributionTest::ERROR_TOLERANCE);
 
         $expectedSigma = sqrt(((BasicMath::square(5) * BasicMath::square(7)) / (BasicMath::square(5) + BasicMath::square(7))));
@@ -74,7 +74,7 @@ class GaussianDistributionTest extends TestCase
         $this->assertEqualsWithDelta(2.0, $productDividedByStandardNormal->getMean(), GaussianDistributionTest::ERROR_TOLERANCE);
         $this->assertEqualsWithDelta(3.0, $productDividedByStandardNormal->getStandardDeviation(), GaussianDistributionTest::ERROR_TOLERANCE);
 
-        $product2              = new GaussianDistribution((4 * BasicMath::square(7) + 6 * BasicMath::square(5)) / (BasicMath::square(5) + BasicMath::square(7)), sqrt(((BasicMath::square(5) * BasicMath::square(7)) / (BasicMath::square(5) + BasicMath::square(7)))));
+        $product2              = new GaussianDistribution((4.0 * BasicMath::square(7) + 6.0 * BasicMath::square(5)) / (BasicMath::square(5) + BasicMath::square(7)), sqrt(((BasicMath::square(5) * BasicMath::square(7)) / (BasicMath::square(5) + BasicMath::square(7)))));
         $m4s5                  = new GaussianDistribution(4, 5);
         $product2DividedByM4S5 = GaussianDistribution::divide($product2, $m4s5);
         $this->assertEqualsWithDelta(6.0, $product2DividedByM4S5->getMean(), GaussianDistributionTest::ERROR_TOLERANCE);

tests/Numerics/MatrixTest.php

@@ -20,7 +20,7 @@ use Exception;
 #[CoversClass(DiagonalMatrix::class)]
 #[CoversClass(Vector::class)]
 // phpcs:disable PSR2.Methods.FunctionCallSignature,Generic.Functions.FunctionCallArgumentSpacing.TooMuchSpaceAfterComma
-class MatrixTest extends TestCase
+final class MatrixTest extends TestCase
 {
     public function testEmptyMatrix(): void
     {
@@ -295,7 +295,7 @@ class MatrixTest extends TestCase
                               1, 0, 6);
 
         $cInverse = $c->getInverse();
-        $d = Matrix::scalarMultiply((1.0 / 22), new SquareMatrix(24, -12, -2,
+        $d = Matrix::scalarMultiply((1.0 / 22.0), new SquareMatrix(24, -12, -2,
                                                                   5,   3, -5,
                                                                  -4, 2, 4));
 

tests/Numerics/RangeTest.php

@@ -10,7 +10,7 @@ use PHPUnit\Framework\Attributes\CoversClass;
 use Exception;
 
 #[CoversClass(Range::class)]
-class RangeTest extends TestCase
+final class RangeTest extends TestCase
 {
     public function testConstructInvalidParam(): void
     {

tests/PartialPlayTest.php

@@ -14,7 +14,7 @@ use PHPUnit\Framework\Attributes\UsesClass;
 #[CoversClass(PartialPlay::class)]
 #[UsesClass(Player::class)]
 #[UsesClass(Guard::class)]
-class PartialPlayTest extends TestCase
+final class PartialPlayTest extends TestCase
 {
     public function testgetPartialPlayPercentage(): void
     {

tests/PlayerTest.php

@@ -12,7 +12,7 @@ use PHPUnit\Framework\Attributes\UsesClass;
 
 #[CoversClass(Player::class)]
 #[UsesClass(Guard::class)]
-class PlayerTest extends TestCase
+final class PlayerTest extends TestCase
 {
     public function testPlayerObjectGetterSetter(): void
     {

tests/RankSorterTest.php

@@ -9,7 +9,7 @@ use PHPUnit\Framework\TestCase;
 use PHPUnit\Framework\Attributes\CoversClass;
 
 #[CoversClass(RankSorter::class)]
-class RankSorterTest extends TestCase
+final class RankSorterTest extends TestCase
 {
     public function testSort(): void
     {

tests/RatingContainerTest.php

@@ -18,7 +18,7 @@ use PHPUnit\Framework\Attributes\UsesClass;
 #[UsesClass(Player::class)]
 #[UsesClass(Rating::class)]
 #[UsesClass(Guard::class)]
-class RatingContainerTest extends TestCase
+final class RatingContainerTest extends TestCase
 {
     public function testRatingContainer(): void
     {

tests/RatingTest.php

@@ -14,7 +14,7 @@ use PHPUnit\Framework\Attributes\UsesClass;
 #[CoversClass(Rating::class)]
 #[UsesClass(BasicMath::class)]
 #[UsesClass(GaussianDistribution::class)]
-class RatingTest extends TestCase
+final class RatingTest extends TestCase
 {
     public function testGetRatingParameters(): void
     {

tests/SkillCalculatorTest.php

@@ -17,7 +17,7 @@ use PHPUnit\Framework\Attributes\RequiresPhpunit;
 #[UsesClass(PlayersRange::class)]
 #[UsesClass(TeamsRange::class)]
 #[RequiresPhpunit('<12.0')]
-class SkillCalculatorTest extends TestCase
+final class SkillCalculatorTest extends TestCase
 {
     public function testisSupported(): void
     {

tests/TeamTest.php

@@ -20,7 +20,7 @@ use PHPUnit\Framework\Attributes\UsesClass;
 #[UsesClass(Player::class)]
 #[UsesClass(Rating::class)]
 #[UsesClass(Guard::class)]
-class TeamTest extends TestCase
+final class TeamTest extends TestCase
 {
     public function testTeam(): void
     {

tests/TrueSkill/DrawMarginTest.php

@@ -14,7 +14,7 @@ use PHPUnit\Framework\Attributes\UsesClass;
 #[CoversClass(DrawMargin::class)]
 #[UsesClass(BasicMath::class)]
 #[UsesClass(GaussianDistribution::class)]
-class DrawMarginTest extends TestCase
+final class DrawMarginTest extends TestCase
 {
     private const float ERROR_TOLERANCE = 0.000001;
 

tests/TrueSkill/FactorGraphTrueSkillCalculatorTest.php

@@ -19,7 +19,7 @@ use PHPUnit\Framework\Attributes\UsesClass;
 #[UsesClass(\DNW\Skills\PlayersRange::class)]
 #[UsesClass(\DNW\Skills\SkillCalculator::class)]
 #[UsesClass(\DNW\Skills\TeamsRange::class)]
-class FactorGraphTrueSkillCalculatorTest extends TestCase
+final class FactorGraphTrueSkillCalculatorTest extends TestCase
 {
     #[CoversNothing]
     public function testMicrosoftResearchExample(): void

tests/TrueSkill/TrueSkillCalculatorTests.php

@@ -11,7 +11,7 @@ use DNW\Skills\SkillCalculator;
 use DNW\Skills\Team;
 use PHPUnit\Framework\TestCase;
 
-class TrueSkillCalculatorTests
+final class TrueSkillCalculatorTests
 {
     private const float ERROR_TOLERANCE_TRUESKILL = 0.085;
 

tests/TrueSkill/TruncatedGaussianCorrectionFunctionsTest.php

@@ -14,7 +14,7 @@ use PHPUnit\Framework\Attributes\UsesClass;
 #[CoversClass(TruncatedGaussianCorrectionFunctions::class)]
 #[UsesClass(BasicMath::class)]
 #[UsesClass(GaussianDistribution::class)]
-class TruncatedGaussianCorrectionFunctionsTest extends TestCase
+final class TruncatedGaussianCorrectionFunctionsTest extends TestCase
 {
     public function testvGreaterThan(): void
     {

tests/TrueSkill/TwoPlayerTrueSkillCalculatorTest.php

@@ -10,7 +10,7 @@ use PHPUnit\Framework\Attributes\CoversClass;
 use PHPUnit\Framework\Attributes\CoversNothing;
 
 #[CoversClass(TwoPlayerTrueSkillCalculator::class)]
-class TwoPlayerTrueSkillCalculatorTest extends TestCase
+final class TwoPlayerTrueSkillCalculatorTest extends TestCase
 {
     #[CoversNothing]
     public function testTwoPlayerTrueSkillCalculator(): void

tests/TrueSkill/TwoTeamTrueSkillCalculatorTest.php

@@ -10,7 +10,7 @@ use PHPUnit\Framework\Attributes\CoversClass;
 use PHPUnit\Framework\Attributes\CoversNothing;
 
 #[CoversClass(TwoTeamTrueSkillCalculator::class)]
-class TwoTeamTrueSkillCalculatorTest extends TestCase
+final class TwoTeamTrueSkillCalculatorTest extends TestCase
 {
     #[CoversNothing]
     public function testTwoTeamTrueSkillCalculator(): void