fix param casting for hhvm compatibility

src/Phpml/Clustering/KMeans/Point.php

@@ -49,7 +49,7 @@ public function getDistanceWith(self $point, $precise = true)
             $distance  += $difference * $difference;
         }
 
-        return $precise ? sqrt($distance) : $distance;
+        return $precise ? sqrt((float)$distance) : $distance;
     }
 
     /**

src/Phpml/Math/Distance/Euclidean.php

@@ -30,6 +30,6 @@ public function distance(array $a, array $b): float
             $distance += pow($a[$i] - $b[$i], 2);
         }
 
-        return sqrt($distance);
+        return sqrt((float)$distance);
     }
 }

src/Phpml/Math/Matrix.php

@@ -147,7 +147,7 @@ private function calculateDeterminant()
             for ($j = 0; $j < $this->columns; ++$j) {
                 $subMatrix = $this->crossOut(0, $j);
                 $minor = $this->matrix[0][$j] * $subMatrix->getDeterminant();
-                $determinant += fmod($j, 2) == 0 ? $minor : -$minor;
+                $determinant += fmod((float)$j, 2.0) == 0 ? $minor : -$minor;
             }
         }
 
@@ -236,7 +236,7 @@ public function inverse()
         for ($i = 0; $i < $this->rows; ++$i) {
             for ($j = 0; $j < $this->columns; ++$j) {
                 $minor = $this->crossOut($i, $j)->getDeterminant();
-                $newMatrix[$i][$j] = fmod($i + $j, 2) == 0 ? $minor : -$minor;
+                $newMatrix[$i][$j] = fmod((float)($i + $j), 2.0) == 0 ? $minor : -$minor;
             }
         }
 

src/Phpml/Math/Statistic/Correlation.php

@@ -38,7 +38,7 @@ public static function pearson(array $x, array $y)
             $b2 = $b2 + pow($b, 2);
         }
 
-        $corr = $axb / sqrt($a2 * $b2);
+        $corr = $axb / sqrt((float)($a2 * $b2));
 
         return $corr;
     }

src/Phpml/Math/Statistic/StandardDeviation.php

@@ -39,6 +39,6 @@ public static function population(array $a, $sample = true)
             --$n;
         }
 
-        return sqrt($carry / $n);
+        return sqrt((float)($carry / $n));
     }
 }