From 03208332ae186460a5f4a2e2a7464dd886e6d738 Mon Sep 17 00:00:00 2001
From: Dennis Eichhorn <spl1nes.com@googlemail.com>
Date: Fri, 23 Feb 2018 17:55:17 +0100
Subject: [PATCH] Fix error bugs

---
 Math/Functions/Functions.php           | 4 ++--
 Math/Statistic/Forecast/Error.php      | 4 ++--
 tests/Math/Functions/FunctionsTest.php | 4 ++--
 3 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/Math/Functions/Functions.php b/Math/Functions/Functions.php
index 82d9ff418..79ca16a8a 100644
--- a/Math/Functions/Functions.php
+++ b/Math/Functions/Functions.php
@@ -258,7 +258,7 @@ class Functions
         $squared = [];
 
         foreach ($values as $value) {
-            $squared[] = $value * $exp;
+            $squared[] = $value ** $exp;
         }
 
         return $squared;
@@ -280,7 +280,7 @@ class Functions
         $squared = [];
 
         foreach ($values as $value) {
-            $squared[] = $value * $exp;
+            $squared[] = $value ** $exp;
         }
 
         return $squared;
diff --git a/Math/Statistic/Forecast/Error.php b/Math/Statistic/Forecast/Error.php
index 74afcc5ab..e8c0ff10b 100644
--- a/Math/Statistic/Forecast/Error.php
+++ b/Math/Statistic/Forecast/Error.php
@@ -111,7 +111,7 @@ class Error
      */
     public static function getMeanAbsoulteError(array $errors) : float
     {
-        return Average::arithmeticMean(Functions::abs($errors));
+        return MeasureOfDispersion::meanAbsoluteDeviation($errors);
     }
 
     /**
@@ -125,7 +125,7 @@ class Error
      */
     public static function getMeanSquaredError(array $errors) : float
     {
-        return Average::arithmeticMean(Functions::powerInt($errors, 2));
+        return MeasureOfDispersion::squaredMeanDeviation($errors);
     }
 
     /**
diff --git a/tests/Math/Functions/FunctionsTest.php b/tests/Math/Functions/FunctionsTest.php
index 7dc9e2aed..9fa493b10 100644
--- a/tests/Math/Functions/FunctionsTest.php
+++ b/tests/Math/Functions/FunctionsTest.php
@@ -74,7 +74,7 @@ class FunctionsTest extends \PHPUnit\Framework\TestCase
         self::assertEquals([4, 9, 16], Functions::powerInt([2, 3, 4], 2));
         self::assertEquals([8, 27, 64], Functions::powerInt([2, 3, 4], 3));
         
-        self::assertEquals([2, 3, 8], Functions::powerFloat([4, 9, 16], 1/2), '', 0.0);
-        self::assertEquals([2, 3, 8], Functions::powerFloat([8, 27, 64], 1/3), '', 0.0);
+        self::assertEquals([2.0, 3.0, 4.0], Functions::powerFloat([4, 9, 16], 1/2), '', 0.0);
+        self::assertEquals([2.0, 3.0, 4.0], Functions::powerFloat([8, 27, 64], 1/3), '', 0.0);
     }
 }