diff --git a/Math/Matrix/Matrix.php b/Math/Matrix/Matrix.php
index 93cd57c72..21c8907f7 100755
--- a/Math/Matrix/Matrix.php
+++ b/Math/Matrix/Matrix.php
@@ -889,7 +889,9 @@ class Matrix implements \ArrayAccess, \Iterator
         $eig = new EigenvalueDecomposition($this);
 
         $d = $eig->getD();
-        for ($i = 0; $d->getM(); ++$i) {
+        $m = $d->getM();
+
+        for ($i = 0; $i < $m; ++$i) {
             $d->matrix[$i][$i] = \pow($d->matrix[$i][$i], $exponent);
         }