diff --git a/Classes/PHPExcel/Shared/trend/bestFitClass.php b/Classes/PHPExcel/Shared/trend/bestFitClass.php
index 1e547b2f..2de029f9 100644
--- a/Classes/PHPExcel/Shared/trend/bestFitClass.php
+++ b/Classes/PHPExcel/Shared/trend/bestFitClass.php
@@ -1,6 +1,7 @@
 <?php
+
 /**
- * PHPExcel
+ * PHPExcel_Best_Fit
  *
  * Copyright (c) 2006 - 2015 PHPExcel
  *
@@ -24,14 +25,6 @@
  * @license    http://www.gnu.org/licenses/old-licenses/lgpl-2.1.txt    LGPL
  * @version    ##VERSION##, ##DATE##
  */
-
-/**
- * PHPExcel_Best_Fit
- *
- * @category   PHPExcel
- * @package    PHPExcel_Shared_Trend
- * @copyright  Copyright (c) 2006 - 2015 PHPExcel (http://www.codeplex.com/PHPExcel)
- */
 class PHPExcel_Best_Fit
 {
     /**
@@ -39,89 +32,89 @@ class PHPExcel_Best_Fit
      *
      * @var    boolean
      **/
-    protected $_error                = false;
+    protected $error = false;
 
     /**
      * Algorithm type to use for best-fit
      *
      * @var    string
      **/
-    protected $_bestFitType            = 'undetermined';
+    protected $bestFitType = 'undetermined';
 
     /**
      * Number of entries in the sets of x- and y-value arrays
      *
      * @var    int
      **/
-    protected $_valueCount            = 0;
+    protected $valueCount = 0;
 
     /**
      * X-value dataseries of values
      *
      * @var    float[]
      **/
-    protected $_xValues                = array();
+    protected $xValues = array();
 
     /**
      * Y-value dataseries of values
      *
      * @var    float[]
      **/
-    protected $_yValues                = array();
+    protected $yValues = array();
 
     /**
      * Flag indicating whether values should be adjusted to Y=0
      *
      * @var    boolean
      **/
-    protected $_adjustToZero        = false;
+    protected $adjustToZero = false;
 
     /**
      * Y-value series of best-fit values
      *
      * @var    float[]
      **/
-    protected $_yBestFitValues        = array();
+    protected $yBestFitValues = array();
 
-    protected $_goodnessOfFit         = 1;
+    protected $goodnessOfFit = 1;
 
-    protected $_stdevOfResiduals    = 0;
+    protected $stdevOfResiduals = 0;
 
-    protected $_covariance            = 0;
+    protected $covariance = 0;
 
-    protected $_correlation            = 0;
+    protected $correlation = 0;
 
-    protected $_SSRegression        = 0;
+    protected $SSRegression = 0;
 
-    protected $_SSResiduals            = 0;
+    protected $SSResiduals = 0;
 
-    protected $_DFResiduals            = 0;
+    protected $DFResiduals = 0;
 
-    protected $_F                    = 0;
+    protected $f = 0;
 
-    protected $_slope                = 0;
+    protected $slope = 0;
 
-    protected $_slopeSE                = 0;
+    protected $slopeSE = 0;
 
-    protected $_intersect            = 0;
+    protected $intersect = 0;
 
-    protected $_intersectSE            = 0;
+    protected $intersectSE = 0;
 
-    protected $_Xoffset                = 0;
+    protected $xOffset = 0;
 
-    protected $_Yoffset                = 0;
+    protected $yOffset = 0;
 
 
     public function getError()
     {
-        return $this->_error;
-    }    //    function getBestFitType()
+        return $this->error;
+    }
 
 
     public function getBestFitType()
     {
-        return $this->_bestFitType;
-    }    //    function getBestFitType()
+        return $this->bestFitType;
+    }
 
     /**
      * Return the Y-Value for a specified value of X
@@ -132,7 +125,7 @@ class PHPExcel_Best_Fit
     public function getValueOfYForX($xValue)
     {
         return false;
-    }    //    function getValueOfYForX()
+    }
 
     /**
      * Return the X-Value for a specified value of Y
@@ -143,7 +136,7 @@ class PHPExcel_Best_Fit
     public function getValueOfXForY($yValue)
     {
         return false;
-    }    //    function getValueOfXForY()
+    }
 
     /**
      * Return the original set of X-Values
@@ -152,8 +145,8 @@ class PHPExcel_Best_Fit
      */
     public function getXValues()
     {
-        return $this->_xValues;
-    }    //    function getValueOfXForY()
+        return $this->xValues;
+    }
 
     /**
      * Return the Equation of the best-fit line
@@ -164,7 +157,7 @@ class PHPExcel_Best_Fit
     public function getEquation($dp = 0)
     {
         return false;
-    }    //    function getEquation()
+    }
 
     /**
      * Return the Slope of the line
@@ -175,10 +168,10 @@ class PHPExcel_Best_Fit
     public function getSlope($dp = 0)
     {
         if ($dp != 0) {
-            return round($this->_slope, $dp);
+            return round($this->slope, $dp);
         }
-        return $this->_slope;
-    }    //    function getSlope()
+        return $this->slope;
+    }
 
     /**
      * Return the standard error of the Slope
@@ -189,10 +182,10 @@ class PHPExcel_Best_Fit
     public function getSlopeSE($dp = 0)
     {
         if ($dp != 0) {
-            return round($this->_slopeSE, $dp);
+            return round($this->slopeSE, $dp);
         }
-        return $this->_slopeSE;
-    }    //    function getSlopeSE()
+        return $this->slopeSE;
+    }
 
     /**
      * Return the Value of X where it intersects Y = 0
@@ -203,10 +196,10 @@ class PHPExcel_Best_Fit
     public function getIntersect($dp = 0)
     {
         if ($dp != 0) {
-            return round($this->_intersect, $dp);
+            return round($this->intersect, $dp);
         }
-        return $this->_intersect;
-    }    //    function getIntersect()
+        return $this->intersect;
+    }
 
     /**
      * Return the standard error of the Intersect
@@ -217,10 +210,10 @@ class PHPExcel_Best_Fit
     public function getIntersectSE($dp = 0)
     {
         if ($dp != 0) {
-            return round($this->_intersectSE, $dp);
+            return round($this->intersectSE, $dp);
         }
-        return $this->_intersectSE;
-    }    //    function getIntersectSE()
+        return $this->intersectSE;
+    }
 
     /**
      * Return the goodness of fit for this regression
@@ -231,18 +224,18 @@ class PHPExcel_Best_Fit
     public function getGoodnessOfFit($dp = 0)
     {
         if ($dp != 0) {
-            return round($this->_goodnessOfFit, $dp);
+            return round($this->goodnessOfFit, $dp);
         }
-        return $this->_goodnessOfFit;
-    }    //    function getGoodnessOfFit()
+        return $this->goodnessOfFit;
+    }
 
     public function getGoodnessOfFitPercent($dp = 0)
     {
         if ($dp != 0) {
-            return round($this->_goodnessOfFit * 100, $dp);
+            return round($this->goodnessOfFit * 100, $dp);
         }
-        return $this->_goodnessOfFit * 100;
-    }    //    function getGoodnessOfFitPercent()
+        return $this->goodnessOfFit * 100;
+    }
 
     /**
      * Return the standard deviation of the residuals for this regression
@@ -253,127 +246,127 @@ class PHPExcel_Best_Fit
     public function getStdevOfResiduals($dp = 0)
     {
         if ($dp != 0) {
-            return round($this->_stdevOfResiduals, $dp);
+            return round($this->stdevOfResiduals, $dp);
         }
-        return $this->_stdevOfResiduals;
-    }    //    function getStdevOfResiduals()
+        return $this->stdevOfResiduals;
+    }
 
     public function getSSRegression($dp = 0)
     {
         if ($dp != 0) {
-            return round($this->_SSRegression, $dp);
+            return round($this->SSRegression, $dp);
         }
-        return $this->_SSRegression;
-    }    //    function getSSRegression()
+        return $this->SSRegression;
+    }
 
     public function getSSResiduals($dp = 0)
     {
         if ($dp != 0) {
-            return round($this->_SSResiduals, $dp);
+            return round($this->SSResiduals, $dp);
         }
-        return $this->_SSResiduals;
-    }    //    function getSSResiduals()
+        return $this->SSResiduals;
+    }
 
     public function getDFResiduals($dp = 0)
     {
         if ($dp != 0) {
-            return round($this->_DFResiduals, $dp);
+            return round($this->DFResiduals, $dp);
         }
-        return $this->_DFResiduals;
-    }    //    function getDFResiduals()
+        return $this->DFResiduals;
+    }
 
     public function getF($dp = 0)
     {
         if ($dp != 0) {
-            return round($this->_F, $dp);
+            return round($this->f, $dp);
         }
-        return $this->_F;
-    }    //    function getF()
+        return $this->f;
+    }
 
     public function getCovariance($dp = 0)
     {
         if ($dp != 0) {
-            return round($this->_covariance, $dp);
+            return round($this->covariance, $dp);
         }
-        return $this->_covariance;
-    }    //    function getCovariance()
+        return $this->covariance;
+    }
 
     public function getCorrelation($dp = 0)
     {
         if ($dp != 0) {
-            return round($this->_correlation, $dp);
+            return round($this->correlation, $dp);
         }
-        return $this->_correlation;
-    }    //    function getCorrelation()
+        return $this->correlation;
+    }
 
     public function getYBestFitValues()
     {
-        return $this->_yBestFitValues;
-    }    //    function getYBestFitValues()
+        return $this->yBestFitValues;
+    }
 
-    protected function _calculateGoodnessOfFit($sumX, $sumY, $sumX2, $sumY2, $sumXY, $meanX, $meanY, $const)
+    protected function calculateGoodnessOfFit($sumX, $sumY, $sumX2, $sumY2, $sumXY, $meanX, $meanY, $const)
     {
         $SSres = $SScov = $SScor = $SStot = $SSsex = 0.0;
-        foreach ($this->_xValues as $xKey => $xValue) {
-            $bestFitY = $this->_yBestFitValues[$xKey] = $this->getValueOfYForX($xValue);
+        foreach ($this->xValues as $xKey => $xValue) {
+            $bestFitY = $this->yBestFitValues[$xKey] = $this->getValueOfYForX($xValue);
 
-            $SSres += ($this->_yValues[$xKey] - $bestFitY) * ($this->_yValues[$xKey] - $bestFitY);
+            $SSres += ($this->yValues[$xKey] - $bestFitY) * ($this->yValues[$xKey] - $bestFitY);
             if ($const) {
-                $SStot += ($this->_yValues[$xKey] - $meanY) * ($this->_yValues[$xKey] - $meanY);
+                $SStot += ($this->yValues[$xKey] - $meanY) * ($this->yValues[$xKey] - $meanY);
             } else {
-                $SStot += $this->_yValues[$xKey] * $this->_yValues[$xKey];
+                $SStot += $this->yValues[$xKey] * $this->yValues[$xKey];
             }
-            $SScov += ($this->_xValues[$xKey] - $meanX) * ($this->_yValues[$xKey] - $meanY);
+            $SScov += ($this->xValues[$xKey] - $meanX) * ($this->yValues[$xKey] - $meanY);
             if ($const) {
-                $SSsex += ($this->_xValues[$xKey] - $meanX) * ($this->_xValues[$xKey] - $meanX);
+                $SSsex += ($this->xValues[$xKey] - $meanX) * ($this->xValues[$xKey] - $meanX);
             } else {
-                $SSsex += $this->_xValues[$xKey] * $this->_xValues[$xKey];
+                $SSsex += $this->xValues[$xKey] * $this->xValues[$xKey];
             }
         }
 
-        $this->_SSResiduals = $SSres;
-        $this->_DFResiduals = $this->_valueCount - 1 - $const;
+        $this->SSResiduals = $SSres;
+        $this->DFResiduals = $this->valueCount - 1 - $const;
 
-        if ($this->_DFResiduals == 0.0) {
-            $this->_stdevOfResiduals = 0.0;
+        if ($this->DFResiduals == 0.0) {
+            $this->stdevOfResiduals = 0.0;
         } else {
-            $this->_stdevOfResiduals = sqrt($SSres / $this->_DFResiduals);
+            $this->stdevOfResiduals = sqrt($SSres / $this->DFResiduals);
         }
         if (($SStot == 0.0) || ($SSres == $SStot)) {
-            $this->_goodnessOfFit = 1;
+            $this->goodnessOfFit = 1;
         } else {
-            $this->_goodnessOfFit = 1 - ($SSres / $SStot);
+            $this->goodnessOfFit = 1 - ($SSres / $SStot);
         }
 
-        $this->_SSRegression = $this->_goodnessOfFit * $SStot;
-        $this->_covariance = $SScov / $this->_valueCount;
-        $this->_correlation = ($this->_valueCount * $sumXY - $sumX * $sumY) / sqrt(($this->_valueCount * $sumX2 - pow($sumX, 2)) * ($this->_valueCount * $sumY2 - pow($sumY, 2)));
-        $this->_slopeSE = $this->_stdevOfResiduals / sqrt($SSsex);
-        $this->_intersectSE = $this->_stdevOfResiduals * sqrt(1 / ($this->_valueCount - ($sumX * $sumX) / $sumX2));
-        if ($this->_SSResiduals != 0.0) {
-            if ($this->_DFResiduals == 0.0) {
-                $this->_F = 0.0;
+        $this->SSRegression = $this->goodnessOfFit * $SStot;
+        $this->covariance = $SScov / $this->valueCount;
+        $this->correlation = ($this->valueCount * $sumXY - $sumX * $sumY) / sqrt(($this->valueCount * $sumX2 - pow($sumX, 2)) * ($this->valueCount * $sumY2 - pow($sumY, 2)));
+        $this->slopeSE = $this->stdevOfResiduals / sqrt($SSsex);
+        $this->intersectSE = $this->stdevOfResiduals * sqrt(1 / ($this->valueCount - ($sumX * $sumX) / $sumX2));
+        if ($this->SSResiduals != 0.0) {
+            if ($this->DFResiduals == 0.0) {
+                $this->f = 0.0;
             } else {
-                $this->_F = $this->_SSRegression / ($this->_SSResiduals / $this->_DFResiduals);
+                $this->f = $this->SSRegression / ($this->SSResiduals / $this->DFResiduals);
             }
         } else {
-            if ($this->_DFResiduals == 0.0) {
-                $this->_F = 0.0;
+            if ($this->DFResiduals == 0.0) {
+                $this->f = 0.0;
             } else {
-                $this->_F = $this->_SSRegression / $this->_DFResiduals;
+                $this->f = $this->SSRegression / $this->DFResiduals;
             }
         }
-    }    //    function _calculateGoodnessOfFit()
+    }
 
-    protected function _leastSquareFit($yValues, $xValues, $const)
+    protected function leastSquareFit($yValues, $xValues, $const)
     {
         // calculate sums
         $x_sum = array_sum($xValues);
         $y_sum = array_sum($yValues);
-        $meanX = $x_sum / $this->_valueCount;
-        $meanY = $y_sum / $this->_valueCount;
+        $meanX = $x_sum / $this->valueCount;
+        $meanY = $y_sum / $this->valueCount;
         $mBase = $mDivisor = $xx_sum = $xy_sum = $yy_sum = 0.0;
-        for ($i = 0; $i < $this->_valueCount; ++$i) {
+        for ($i = 0; $i < $this->valueCount; ++$i) {
             $xy_sum += $xValues[$i] * $yValues[$i];
             $xx_sum += $xValues[$i] * $xValues[$i];
             $yy_sum += $yValues[$i] * $yValues[$i];
@@ -388,19 +381,19 @@ class PHPExcel_Best_Fit
         }
 
         // calculate slope
-//        $this->_slope = (($this->_valueCount * $xy_sum) - ($x_sum * $y_sum)) / (($this->_valueCount * $xx_sum) - ($x_sum * $x_sum));
-        $this->_slope = $mBase / $mDivisor;
+//        $this->slope = (($this->valueCount * $xy_sum) - ($x_sum * $y_sum)) / (($this->valueCount * $xx_sum) - ($x_sum * $x_sum));
+        $this->slope = $mBase / $mDivisor;
 
         // calculate intersect
-//        $this->_intersect = ($y_sum - ($this->_slope * $x_sum)) / $this->_valueCount;
+//        $this->intersect = ($y_sum - ($this->slope * $x_sum)) / $this->valueCount;
         if ($const) {
-            $this->_intersect = $meanY - ($this->_slope * $meanX);
+            $this->intersect = $meanY - ($this->slope * $meanX);
         } else {
-            $this->_intersect = 0;
+            $this->intersect = 0;
         }
 
-        $this->_calculateGoodnessOfFit($x_sum, $y_sum, $xx_sum, $yy_sum, $xy_sum, $meanX, $meanY, $const);
-    }    //    function _leastSquareFit()
+        $this->calculateGoodnessOfFit($x_sum, $y_sum, $xx_sum, $yy_sum, $xy_sum, $meanX, $meanY, $const);
+    }
 
     /**
      * Define the regression
@@ -421,12 +414,12 @@ class PHPExcel_Best_Fit
             $nX = $nY;
         } elseif ($nY != $nX) {
             //    Ensure both arrays of points are the same size
-            $this->_error = true;
+            $this->error = true;
             return false;
         }
 
-        $this->_valueCount = $nY;
-        $this->_xValues = $xValues;
-        $this->_yValues = $yValues;
-    }    //    function __construct()
+        $this->valueCount = $nY;
+        $this->xValues = $xValues;
+        $this->yValues = $yValues;
+    }
 }
diff --git a/Classes/PHPExcel/Shared/trend/exponentialBestFitClass.php b/Classes/PHPExcel/Shared/trend/exponentialBestFitClass.php
index caa1759c..44487352 100644
--- a/Classes/PHPExcel/Shared/trend/exponentialBestFitClass.php
+++ b/Classes/PHPExcel/Shared/trend/exponentialBestFitClass.php
@@ -1,6 +1,9 @@
 <?php
+
+require_once(PHPEXCEL_ROOT . 'PHPExcel/Shared/trend/bestFitClass.php');
+
 /**
- * PHPExcel
+ * PHPExcel_Exponential_Best_Fit
  *
  * Copyright (c) 2006 - 2015 PHPExcel
  *
@@ -24,18 +27,6 @@
  * @license    http://www.gnu.org/licenses/old-licenses/lgpl-2.1.txt    LGPL
  * @version    ##VERSION##, ##DATE##
  */
-
-
-require_once(PHPEXCEL_ROOT . 'PHPExcel/Shared/trend/bestFitClass.php');
-
-
-/**
- * PHPExcel_Exponential_Best_Fit
- *
- * @category   PHPExcel
- * @package    PHPExcel_Shared_Trend
- * @copyright  Copyright (c) 2006 - 2015 PHPExcel (http://www.codeplex.com/PHPExcel)
- */
 class PHPExcel_Exponential_Best_Fit extends PHPExcel_Best_Fit
 {
     /**
@@ -44,7 +35,7 @@ class PHPExcel_Exponential_Best_Fit extends PHPExcel_Best_Fit
      *
      * @var    string
      **/
-    protected $_bestFitType        = 'exponential';
+    protected $bestFitType        = 'exponential';
 
     /**
      * Return the Y-Value for a specified value of X
@@ -54,8 +45,8 @@ class PHPExcel_Exponential_Best_Fit extends PHPExcel_Best_Fit
      **/
     public function getValueOfYForX($xValue)
     {
-        return $this->getIntersect() * pow($this->getSlope(), ($xValue - $this->_Xoffset));
-    }    //    function getValueOfYForX()
+        return $this->getIntersect() * pow($this->getSlope(), ($xValue - $this->xOffset));
+    }
 
     /**
      * Return the X-Value for a specified value of Y
@@ -65,8 +56,8 @@ class PHPExcel_Exponential_Best_Fit extends PHPExcel_Best_Fit
      **/
     public function getValueOfXForY($yValue)
     {
-        return log(($yValue + $this->_Yoffset) / $this->getIntersect()) / log($this->getSlope());
-    }    //    function getValueOfXForY()
+        return log(($yValue + $this->yOffset) / $this->getIntersect()) / log($this->getSlope());
+    }
 
     /**
      * Return the Equation of the best-fit line
@@ -79,8 +70,8 @@ class PHPExcel_Exponential_Best_Fit extends PHPExcel_Best_Fit
         $slope = $this->getSlope($dp);
         $intersect = $this->getIntersect($dp);
 
-        return 'Y = '.$intersect.' * '.$slope.'^X';
-    }    //    function getEquation()
+        return 'Y = ' . $intersect . ' * ' . $slope . '^X';
+    }
 
     /**
      * Return the Slope of the line
@@ -94,7 +85,7 @@ class PHPExcel_Exponential_Best_Fit extends PHPExcel_Best_Fit
             return round(exp($this->_slope), $dp);
         }
         return exp($this->_slope);
-    }    //    function getSlope()
+    }
 
     /**
      * Return the Value of X where it intersects Y = 0
@@ -105,10 +96,10 @@ class PHPExcel_Exponential_Best_Fit extends PHPExcel_Best_Fit
     public function getIntersect($dp = 0)
     {
         if ($dp != 0) {
-            return round(exp($this->_intersect), $dp);
+            return round(exp($this->intersect), $dp);
         }
-        return exp($this->_intersect);
-    }    //    function getIntersect()
+        return exp($this->intersect);
+    }
 
     /**
      * Execute the regression and calculate the goodness of fit for a set of X and Y data values
@@ -117,7 +108,7 @@ class PHPExcel_Exponential_Best_Fit extends PHPExcel_Best_Fit
      * @param     float[]    $xValues    The set of X-values for this regression
      * @param     boolean    $const
      */
-    private function _exponential_regression($yValues, $xValues, $const)
+    private function exponentialRegression($yValues, $xValues, $const)
     {
         foreach ($yValues as &$value) {
             if ($value < 0.0) {
@@ -128,8 +119,8 @@ class PHPExcel_Exponential_Best_Fit extends PHPExcel_Best_Fit
         }
         unset($value);
 
-        $this->_leastSquareFit($yValues, $xValues, $const);
-    }    //    function _exponential_regression()
+        $this->leastSquareFit($yValues, $xValues, $const);
+    }
 
     /**
      * Define the regression and calculate the goodness of fit for a set of X and Y data values
@@ -141,7 +132,7 @@ class PHPExcel_Exponential_Best_Fit extends PHPExcel_Best_Fit
     public function __construct($yValues, $xValues = array(), $const = true)
     {
         if (parent::__construct($yValues, $xValues) !== false) {
-            $this->_exponential_regression($yValues, $xValues, $const);
+            $this->exponentialRegression($yValues, $xValues, $const);
         }
-    }    //    function __construct()
+    }
 }
diff --git a/Classes/PHPExcel/Shared/trend/linearBestFitClass.php b/Classes/PHPExcel/Shared/trend/linearBestFitClass.php
index c5ed3cf3..76b55b3e 100644
--- a/Classes/PHPExcel/Shared/trend/linearBestFitClass.php
+++ b/Classes/PHPExcel/Shared/trend/linearBestFitClass.php
@@ -1,6 +1,9 @@
 <?php
+
+require_once(PHPEXCEL_ROOT . 'PHPExcel/Shared/trend/bestFitClass.php');
+
 /**
- * PHPExcel
+ * PHPExcel_Linear_Best_Fit
  *
  * Copyright (c) 2006 - 2015 PHPExcel
  *
@@ -24,16 +27,6 @@
  * @license    http://www.gnu.org/licenses/old-licenses/lgpl-2.1.txt    LGPL
  * @version    ##VERSION##, ##DATE##
  */
-
-require_once(PHPEXCEL_ROOT . 'PHPExcel/Shared/trend/bestFitClass.php');
-
-/**
- * PHPExcel_Linear_Best_Fit
- *
- * @category   PHPExcel
- * @package    PHPExcel_Shared_Trend
- * @copyright  Copyright (c) 2006 - 2015 PHPExcel (http://www.codeplex.com/PHPExcel)
- */
 class PHPExcel_Linear_Best_Fit extends PHPExcel_Best_Fit
 {
     /**
@@ -42,7 +35,7 @@ class PHPExcel_Linear_Best_Fit extends PHPExcel_Best_Fit
      *
      * @var    string
      **/
-    protected $_bestFitType        = 'linear';
+    protected $bestFitType        = 'linear';
 
     /**
      * Return the Y-Value for a specified value of X
@@ -53,7 +46,7 @@ class PHPExcel_Linear_Best_Fit extends PHPExcel_Best_Fit
     public function getValueOfYForX($xValue)
     {
         return $this->getIntersect() + $this->getSlope() * $xValue;
-    }    //    function getValueOfYForX()
+    }
 
     /**
      * Return the X-Value for a specified value of Y
@@ -64,7 +57,7 @@ class PHPExcel_Linear_Best_Fit extends PHPExcel_Best_Fit
     public function getValueOfXForY($yValue)
     {
         return ($yValue - $this->getIntersect()) / $this->getSlope();
-    }    //    function getValueOfXForY()
+    }
 
 
     /**
@@ -78,8 +71,8 @@ class PHPExcel_Linear_Best_Fit extends PHPExcel_Best_Fit
         $slope = $this->getSlope($dp);
         $intersect = $this->getIntersect($dp);
 
-        return 'Y = '.$intersect.' + '.$slope.' * X';
-    }    //    function getEquation()
+        return 'Y = ' . $intersect . ' + ' . $slope . ' * X';
+    }
 
     /**
      * Execute the regression and calculate the goodness of fit for a set of X and Y data values
@@ -88,10 +81,10 @@ class PHPExcel_Linear_Best_Fit extends PHPExcel_Best_Fit
      * @param     float[]    $xValues    The set of X-values for this regression
      * @param     boolean    $const
      */
-    private function _linear_regression($yValues, $xValues, $const)
+    private function linearRegression($yValues, $xValues, $const)
     {
-        $this->_leastSquareFit($yValues, $xValues, $const);
-    }    //    function _linear_regression()
+        $this->leastSquareFit($yValues, $xValues, $const);
+    }
 
     /**
      * Define the regression and calculate the goodness of fit for a set of X and Y data values
@@ -103,7 +96,7 @@ class PHPExcel_Linear_Best_Fit extends PHPExcel_Best_Fit
     public function __construct($yValues, $xValues = array(), $const = true)
     {
         if (parent::__construct($yValues, $xValues) !== false) {
-            $this->_linear_regression($yValues, $xValues, $const);
+            $this->linearRegression($yValues, $xValues, $const);
         }
-    }    //    function __construct()
+    }
 }
diff --git a/Classes/PHPExcel/Shared/trend/logarithmicBestFitClass.php b/Classes/PHPExcel/Shared/trend/logarithmicBestFitClass.php
index 7d561cda..221c5386 100644
--- a/Classes/PHPExcel/Shared/trend/logarithmicBestFitClass.php
+++ b/Classes/PHPExcel/Shared/trend/logarithmicBestFitClass.php
@@ -1,6 +1,9 @@
 <?php
+
+require_once(PHPEXCEL_ROOT . 'PHPExcel/Shared/trend/bestFitClass.php');
+
 /**
- * PHPExcel
+ * PHPExcel_Logarithmic_Best_Fit
  *
  * Copyright (c) 2006 - 2015 PHPExcel
  *
@@ -24,16 +27,6 @@
  * @license    http://www.gnu.org/licenses/old-licenses/lgpl-2.1.txt    LGPL
  * @version    ##VERSION##, ##DATE##
  */
-
-require_once(PHPEXCEL_ROOT . 'PHPExcel/Shared/trend/bestFitClass.php');
-
-/**
- * PHPExcel_Logarithmic_Best_Fit
- *
- * @category   PHPExcel
- * @package    PHPExcel_Shared_Trend
- * @copyright  Copyright (c) 2006 - 2015 PHPExcel (http://www.codeplex.com/PHPExcel)
- */
 class PHPExcel_Logarithmic_Best_Fit extends PHPExcel_Best_Fit
 {
     /**
@@ -42,7 +35,7 @@ class PHPExcel_Logarithmic_Best_Fit extends PHPExcel_Best_Fit
      *
      * @var    string
      **/
-    protected $_bestFitType        = 'logarithmic';
+    protected $bestFitType        = 'logarithmic';
 
     /**
      * Return the Y-Value for a specified value of X
@@ -52,8 +45,8 @@ class PHPExcel_Logarithmic_Best_Fit extends PHPExcel_Best_Fit
      **/
     public function getValueOfYForX($xValue)
     {
-        return $this->getIntersect() + $this->getSlope() * log($xValue - $this->_Xoffset);
-    }    //    function getValueOfYForX()
+        return $this->getIntersect() + $this->getSlope() * log($xValue - $this->xOffset);
+    }
 
     /**
      * Return the X-Value for a specified value of Y
@@ -64,7 +57,7 @@ class PHPExcel_Logarithmic_Best_Fit extends PHPExcel_Best_Fit
     public function getValueOfXForY($yValue)
     {
         return exp(($yValue - $this->getIntersect()) / $this->getSlope());
-    }    //    function getValueOfXForY()
+    }
 
     /**
      * Return the Equation of the best-fit line
@@ -78,7 +71,7 @@ class PHPExcel_Logarithmic_Best_Fit extends PHPExcel_Best_Fit
         $intersect = $this->getIntersect($dp);
 
         return 'Y = '.$intersect.' + '.$slope.' * log(X)';
-    }    //    function getEquation()
+    }
 
     /**
      * Execute the regression and calculate the goodness of fit for a set of X and Y data values
@@ -87,7 +80,7 @@ class PHPExcel_Logarithmic_Best_Fit extends PHPExcel_Best_Fit
      * @param     float[]    $xValues    The set of X-values for this regression
      * @param     boolean    $const
      */
-    private function _logarithmic_regression($yValues, $xValues, $const)
+    private function logarithmicRegression($yValues, $xValues, $const)
     {
         foreach ($xValues as &$value) {
             if ($value < 0.0) {
@@ -98,8 +91,8 @@ class PHPExcel_Logarithmic_Best_Fit extends PHPExcel_Best_Fit
         }
         unset($value);
 
-        $this->_leastSquareFit($yValues, $xValues, $const);
-    }    //    function _logarithmic_regression()
+        $this->leastSquareFit($yValues, $xValues, $const);
+    }
 
     /**
      * Define the regression and calculate the goodness of fit for a set of X and Y data values
@@ -111,7 +104,7 @@ class PHPExcel_Logarithmic_Best_Fit extends PHPExcel_Best_Fit
     public function __construct($yValues, $xValues = array(), $const = true)
     {
         if (parent::__construct($yValues, $xValues) !== false) {
-            $this->_logarithmic_regression($yValues, $xValues, $const);
+            $this->logarithmicRegression($yValues, $xValues, $const);
         }
-    }    //    function __construct()
+    }
 }
diff --git a/Classes/PHPExcel/Shared/trend/polynomialBestFitClass.php b/Classes/PHPExcel/Shared/trend/polynomialBestFitClass.php
index b1b69b0a..8a882b74 100644
--- a/Classes/PHPExcel/Shared/trend/polynomialBestFitClass.php
+++ b/Classes/PHPExcel/Shared/trend/polynomialBestFitClass.php
@@ -1,6 +1,10 @@
 <?php
+
+require_once PHPEXCEL_ROOT . 'PHPExcel/Shared/trend/bestFitClass.php';
+require_once PHPEXCEL_ROOT . 'PHPExcel/Shared/JAMA/Matrix.php';
+
 /**
- * PHPExcel
+ * PHPExcel_Polynomial_Best_Fit
  *
  * Copyright (c) 2006 - 2015 PHPExcel
  *
@@ -24,19 +28,6 @@
  * @license    http://www.gnu.org/licenses/old-licenses/lgpl-2.1.txt    LGPL
  * @version    ##VERSION##, ##DATE##
  */
-
-
-require_once PHPEXCEL_ROOT . 'PHPExcel/Shared/trend/bestFitClass.php';
-require_once PHPEXCEL_ROOT . 'PHPExcel/Shared/JAMA/Matrix.php';
-
-
-/**
- * PHPExcel_Polynomial_Best_Fit
- *
- * @category   PHPExcel
- * @package    PHPExcel_Shared_Trend
- * @copyright  Copyright (c) 2006 - 2015 PHPExcel (http://www.codeplex.com/PHPExcel)
- */
 class PHPExcel_Polynomial_Best_Fit extends PHPExcel_Best_Fit
 {
     /**
@@ -45,7 +36,7 @@ class PHPExcel_Polynomial_Best_Fit extends PHPExcel_Best_Fit
      *
      * @var    string
      **/
-    protected $_bestFitType        = 'polynomial';
+    protected $bestFitType = 'polynomial';
 
     /**
      * Polynomial order
@@ -53,7 +44,7 @@ class PHPExcel_Polynomial_Best_Fit extends PHPExcel_Best_Fit
      * @protected
      * @var    int
      **/
-    protected $_order            = 0;
+    protected $order = 0;
 
 
     /**
@@ -63,8 +54,8 @@ class PHPExcel_Polynomial_Best_Fit extends PHPExcel_Best_Fit
      **/
     public function getOrder()
     {
-        return $this->_order;
-    }    //    function getOrder()
+        return $this->order;
+    }
 
 
     /**
@@ -83,7 +74,7 @@ class PHPExcel_Polynomial_Best_Fit extends PHPExcel_Best_Fit
             }
         }
         return $retVal;
-    }    //    function getValueOfYForX()
+    }
 
 
     /**
@@ -95,7 +86,7 @@ class PHPExcel_Polynomial_Best_Fit extends PHPExcel_Best_Fit
     public function getValueOfXForY($yValue)
     {
         return ($yValue - $this->getIntersect()) / $this->getSlope();
-    }    //    function getValueOfXForY()
+    }
 
 
     /**
@@ -109,17 +100,17 @@ class PHPExcel_Polynomial_Best_Fit extends PHPExcel_Best_Fit
         $slope = $this->getSlope($dp);
         $intersect = $this->getIntersect($dp);
 
-        $equation = 'Y = '.$intersect;
+        $equation = 'Y = ' . $intersect;
         foreach ($slope as $key => $value) {
             if ($value != 0.0) {
-                $equation .= ' + '.$value.' * X';
+                $equation .= ' + ' . $value . ' * X';
                 if ($key > 0) {
-                    $equation .= '^'.($key + 1);
+                    $equation .= '^' . ($key + 1);
                 }
             }
         }
         return $equation;
-    }    //    function getEquation()
+    }
 
 
     /**
@@ -138,13 +129,13 @@ class PHPExcel_Polynomial_Best_Fit extends PHPExcel_Best_Fit
             return $coefficients;
         }
         return $this->_slope;
-    }    //    function getSlope()
+    }
 
 
     public function getCoefficients($dp = 0)
     {
         return array_merge(array($this->getIntersect($dp)), $this->getSlope($dp));
-    }    //    function getCoefficients()
+    }
 
 
     /**
@@ -155,13 +146,13 @@ class PHPExcel_Polynomial_Best_Fit extends PHPExcel_Best_Fit
      * @param    float[]        $xValues    The set of X-values for this regression
      * @param    boolean        $const
      */
-    private function _polynomial_regression($order, $yValues, $xValues, $const)
+    private function polynomialRegression($order, $yValues, $xValues, $const)
     {
         // calculate sums
         $x_sum = array_sum($xValues);
         $y_sum = array_sum($yValues);
         $xx_sum = $xy_sum = 0;
-        for ($i = 0; $i < $this->_valueCount; ++$i) {
+        for ($i = 0; $i < $this->valueCount; ++$i) {
             $xy_sum += $xValues[$i] * $yValues[$i];
             $xx_sum += $xValues[$i] * $xValues[$i];
             $yy_sum += $yValues[$i] * $yValues[$i];
@@ -174,12 +165,12 @@ class PHPExcel_Polynomial_Best_Fit extends PHPExcel_Best_Fit
          *    a series of x-y data points using least squares.
          *
          */
-        for ($i = 0; $i < $this->_valueCount; ++$i) {
+        for ($i = 0; $i < $this->valueCount; ++$i) {
             for ($j = 0; $j <= $order; ++$j) {
                 $A[$i][$j] = pow($xValues[$i], $j);
             }
         }
-        for ($i=0; $i < $this->_valueCount; ++$i) {
+        for ($i=0; $i < $this->valueCount; ++$i) {
             $B[$i] = array($yValues[$i]);
         }
         $matrixA = new Matrix($A);
@@ -195,14 +186,14 @@ class PHPExcel_Polynomial_Best_Fit extends PHPExcel_Best_Fit
             $coefficients[] = $r;
         }
 
-        $this->_intersect = array_shift($coefficients);
+        $this->intersect = array_shift($coefficients);
         $this->_slope = $coefficients;
 
-        $this->_calculateGoodnessOfFit($x_sum, $y_sum, $xx_sum, $yy_sum, $xy_sum);
-        foreach ($this->_xValues as $xKey => $xValue) {
-            $this->_yBestFitValues[$xKey] = $this->getValueOfYForX($xValue);
+        $this->calculateGoodnessOfFit($x_sum, $y_sum, $xx_sum, $yy_sum, $xy_sum);
+        foreach ($this->xValues as $xKey => $xValue) {
+            $this->yBestFitValues[$xKey] = $this->getValueOfYForX($xValue);
         }
-    }    //    function _polynomial_regression()
+    }
 
 
     /**
@@ -216,10 +207,10 @@ class PHPExcel_Polynomial_Best_Fit extends PHPExcel_Best_Fit
     public function __construct($order, $yValues, $xValues = array(), $const = true)
     {
         if (parent::__construct($yValues, $xValues) !== false) {
-            if ($order < $this->_valueCount) {
-                $this->_bestFitType .= '_'.$order;
-                $this->_order = $order;
-                $this->_polynomial_regression($order, $yValues, $xValues, $const);
+            if ($order < $this->valueCount) {
+                $this->bestFitType .= '_'.$order;
+                $this->order = $order;
+                $this->polynomialRegression($order, $yValues, $xValues, $const);
                 if (($this->getGoodnessOfFit() < 0.0) || ($this->getGoodnessOfFit() > 1.0)) {
                     $this->_error = true;
                 }
@@ -227,5 +218,5 @@ class PHPExcel_Polynomial_Best_Fit extends PHPExcel_Best_Fit
                 $this->_error = true;
             }
         }
-    }    //    function __construct()
+    }
 }
diff --git a/Classes/PHPExcel/Shared/trend/powerBestFitClass.php b/Classes/PHPExcel/Shared/trend/powerBestFitClass.php
index 38870af8..77c47342 100644
--- a/Classes/PHPExcel/Shared/trend/powerBestFitClass.php
+++ b/Classes/PHPExcel/Shared/trend/powerBestFitClass.php
@@ -1,6 +1,9 @@
 <?php
+
+require_once PHPEXCEL_ROOT . 'PHPExcel/Shared/trend/bestFitClass.php';
+
 /**
- * PHPExcel
+ * PHPExcel_Power_Best_Fit
  *
  * Copyright (c) 2006 - 2015 PHPExcel
  *
@@ -24,18 +27,6 @@
  * @license    http://www.gnu.org/licenses/old-licenses/lgpl-2.1.txt    LGPL
  * @version    ##VERSION##, ##DATE##
  */
-
-
-require_once PHPEXCEL_ROOT . 'PHPExcel/Shared/trend/bestFitClass.php';
-
-
-/**
- * PHPExcel_Power_Best_Fit
- *
- * @category   PHPExcel
- * @package    PHPExcel_Shared_Trend
- * @copyright  Copyright (c) 2006 - 2015 PHPExcel (http://www.codeplex.com/PHPExcel)
- */
 class PHPExcel_Power_Best_Fit extends PHPExcel_Best_Fit
 {
     /**
@@ -44,7 +35,7 @@ class PHPExcel_Power_Best_Fit extends PHPExcel_Best_Fit
      *
      * @var    string
      **/
-    protected $_bestFitType        = 'power';
+    protected $bestFitType        = 'power';
 
 
     /**
@@ -55,8 +46,8 @@ class PHPExcel_Power_Best_Fit extends PHPExcel_Best_Fit
      **/
     public function getValueOfYForX($xValue)
     {
-        return $this->getIntersect() * pow(($xValue - $this->_Xoffset), $this->getSlope());
-    }    //    function getValueOfYForX()
+        return $this->getIntersect() * pow(($xValue - $this->xOffset), $this->getSlope());
+    }
 
 
     /**
@@ -67,8 +58,8 @@ class PHPExcel_Power_Best_Fit extends PHPExcel_Best_Fit
      **/
     public function getValueOfXForY($yValue)
     {
-        return pow((($yValue + $this->_Yoffset) / $this->getIntersect()), (1 / $this->getSlope()));
-    }    //    function getValueOfXForY()
+        return pow((($yValue + $this->yOffset) / $this->getIntersect()), (1 / $this->getSlope()));
+    }
 
 
     /**
@@ -82,8 +73,8 @@ class PHPExcel_Power_Best_Fit extends PHPExcel_Best_Fit
         $slope = $this->getSlope($dp);
         $intersect = $this->getIntersect($dp);
 
-        return 'Y = '.$intersect.' * X^'.$slope;
-    }    //    function getEquation()
+        return 'Y = ' . $intersect . ' * X^' . $slope;
+    }
 
 
     /**
@@ -95,10 +86,10 @@ class PHPExcel_Power_Best_Fit extends PHPExcel_Best_Fit
     public function getIntersect($dp = 0)
     {
         if ($dp != 0) {
-            return round(exp($this->_intersect), $dp);
+            return round(exp($this->intersect), $dp);
         }
-        return exp($this->_intersect);
-    }    //    function getIntersect()
+        return exp($this->intersect);
+    }
 
 
     /**
@@ -108,7 +99,7 @@ class PHPExcel_Power_Best_Fit extends PHPExcel_Best_Fit
      * @param     float[]    $xValues    The set of X-values for this regression
      * @param     boolean    $const
      */
-    private function _power_regression($yValues, $xValues, $const)
+    private function powerRegression($yValues, $xValues, $const)
     {
         foreach ($xValues as &$value) {
             if ($value < 0.0) {
@@ -127,8 +118,8 @@ class PHPExcel_Power_Best_Fit extends PHPExcel_Best_Fit
         }
         unset($value);
 
-        $this->_leastSquareFit($yValues, $xValues, $const);
-    }    //    function _power_regression()
+        $this->leastSquareFit($yValues, $xValues, $const);
+    }
 
 
     /**
@@ -141,7 +132,7 @@ class PHPExcel_Power_Best_Fit extends PHPExcel_Best_Fit
     public function __construct($yValues, $xValues = array(), $const = true)
     {
         if (parent::__construct($yValues, $xValues) !== false) {
-            $this->_power_regression($yValues, $xValues, $const);
+            $this->powerRegression($yValues, $xValues, $const);
         }
     }
 }
diff --git a/Classes/PHPExcel/Shared/trend/trendClass.php b/Classes/PHPExcel/Shared/trend/trendClass.php
index a7b34ed9..715cd412 100644
--- a/Classes/PHPExcel/Shared/trend/trendClass.php
+++ b/Classes/PHPExcel/Shared/trend/trendClass.php
@@ -1,6 +1,13 @@
 <?php
+
+require_once PHPEXCEL_ROOT . 'PHPExcel/Shared/trend/linearBestFitClass.php';
+require_once PHPEXCEL_ROOT . 'PHPExcel/Shared/trend/logarithmicBestFitClass.php';
+require_once PHPEXCEL_ROOT . 'PHPExcel/Shared/trend/exponentialBestFitClass.php';
+require_once PHPEXCEL_ROOT . 'PHPExcel/Shared/trend/powerBestFitClass.php';
+require_once PHPEXCEL_ROOT . 'PHPExcel/Shared/trend/polynomialBestFitClass.php';
+
 /**
- * PHPExcel
+ * PHPExcel_trendClass
  *
  * Copyright (c) 2006 - 2015 PHPExcel
  *
@@ -24,64 +31,51 @@
  * @license    http://www.gnu.org/licenses/old-licenses/lgpl-2.1.txt    LGPL
  * @version    ##VERSION##, ##DATE##
  */
-
-
-require_once PHPEXCEL_ROOT . 'PHPExcel/Shared/trend/linearBestFitClass.php';
-require_once PHPEXCEL_ROOT . 'PHPExcel/Shared/trend/logarithmicBestFitClass.php';
-require_once PHPEXCEL_ROOT . 'PHPExcel/Shared/trend/exponentialBestFitClass.php';
-require_once PHPEXCEL_ROOT . 'PHPExcel/Shared/trend/powerBestFitClass.php';
-require_once PHPEXCEL_ROOT . 'PHPExcel/Shared/trend/polynomialBestFitClass.php';
-
-
-/**
- * PHPExcel_trendClass
- *
- * @category   PHPExcel
- * @package    PHPExcel_Shared_Trend
- * @copyright  Copyright (c) 2006 - 2015 PHPExcel (http://www.codeplex.com/PHPExcel)
- */
 class trendClass
 {
-    const TREND_LINEAR                = 'Linear';
-    const TREND_LOGARITHMIC            = 'Logarithmic';
-    const TREND_EXPONENTIAL            = 'Exponential';
-    const TREND_POWER                = 'Power';
-    const TREND_POLYNOMIAL_2        = 'Polynomial_2';
-    const TREND_POLYNOMIAL_3        = 'Polynomial_3';
-    const TREND_POLYNOMIAL_4        = 'Polynomial_4';
-    const TREND_POLYNOMIAL_5        = 'Polynomial_5';
-    const TREND_POLYNOMIAL_6        = 'Polynomial_6';
-    const TREND_BEST_FIT            = 'Bestfit';
-    const TREND_BEST_FIT_NO_POLY    = 'Bestfit_no_Polynomials';
+    const TREND_LINEAR            = 'Linear';
+    const TREND_LOGARITHMIC       = 'Logarithmic';
+    const TREND_EXPONENTIAL       = 'Exponential';
+    const TREND_POWER             = 'Power';
+    const TREND_POLYNOMIAL_2      = 'Polynomial_2';
+    const TREND_POLYNOMIAL_3      = 'Polynomial_3';
+    const TREND_POLYNOMIAL_4      = 'Polynomial_4';
+    const TREND_POLYNOMIAL_5      = 'Polynomial_5';
+    const TREND_POLYNOMIAL_6      = 'Polynomial_6';
+    const TREND_BEST_FIT          = 'Bestfit';
+    const TREND_BEST_FIT_NO_POLY  = 'Bestfit_no_Polynomials';
 
     /**
      * Names of the best-fit trend analysis methods
      *
      * @var string[]
      **/
-    private static $_trendTypes = array( self::TREND_LINEAR,
-                                         self::TREND_LOGARITHMIC,
-                                         self::TREND_EXPONENTIAL,
-                                         self::TREND_POWER
-                                       );
+    private static $trendTypes = array(
+        self::TREND_LINEAR,
+        self::TREND_LOGARITHMIC,
+        self::TREND_EXPONENTIAL,
+        self::TREND_POWER
+    );
+
     /**
      * Names of the best-fit trend polynomial orders
      *
      * @var string[]
      **/
-    private static $_trendTypePolyOrders = array( self::TREND_POLYNOMIAL_2,
-                                                  self::TREND_POLYNOMIAL_3,
-                                                  self::TREND_POLYNOMIAL_4,
-                                                  self::TREND_POLYNOMIAL_5,
-                                                  self::TREND_POLYNOMIAL_6
-                                                );
+    private static $trendTypePolynomialOrders = array(
+        self::TREND_POLYNOMIAL_2,
+        self::TREND_POLYNOMIAL_3,
+        self::TREND_POLYNOMIAL_4,
+        self::TREND_POLYNOMIAL_5,
+        self::TREND_POLYNOMIAL_6
+    );
 
     /**
      * Cached results for each method when trying to identify which provides the best fit
      *
      * @var PHPExcel_Best_Fit[]
      **/
-    private static $_trendCache = array();
+    private static $trendCache = array();
 
 
     public static function calculate($trendType = self::TREND_BEST_FIT, $yValues, $xValues = array(), $const = true)
@@ -107,34 +101,32 @@ class trendClass
             case self::TREND_LOGARITHMIC:
             case self::TREND_EXPONENTIAL:
             case self::TREND_POWER:
-                if (!isset(self::$_trendCache[$key])) {
+                if (!isset(self::$trendCache[$key])) {
                     $className = 'PHPExcel_'.$trendType.'_Best_Fit';
-                    self::$_trendCache[$key] = new $className($yValues, $xValues, $const);
+                    self::$trendCache[$key] = new $className($yValues, $xValues, $const);
                 }
-                return self::$_trendCache[$key];
-                break;
+                return self::$trendCache[$key];
             case self::TREND_POLYNOMIAL_2:
             case self::TREND_POLYNOMIAL_3:
             case self::TREND_POLYNOMIAL_4:
             case self::TREND_POLYNOMIAL_5:
             case self::TREND_POLYNOMIAL_6:
-                if (!isset(self::$_trendCache[$key])) {
+                if (!isset(self::$trendCache[$key])) {
                     $order = substr($trendType, -1);
-                    self::$_trendCache[$key] = new PHPExcel_Polynomial_Best_Fit($order, $yValues, $xValues, $const);
+                    self::$trendCache[$key] = new PHPExcel_Polynomial_Best_Fit($order, $yValues, $xValues, $const);
                 }
-                return self::$_trendCache[$key];
-                break;
+                return self::$trendCache[$key];
             case self::TREND_BEST_FIT:
             case self::TREND_BEST_FIT_NO_POLY:
                 //    If the request is to determine the best fit regression, then we test each trend line in turn
                 //    Start by generating an instance of each available trend method
-                foreach (self::$_trendTypes as $trendMethod) {
+                foreach (self::$trendTypes as $trendMethod) {
                     $className = 'PHPExcel_'.$trendMethod.'BestFit';
                     $bestFit[$trendMethod] = new $className($yValues, $xValues, $const);
                     $bestFitValue[$trendMethod] = $bestFit[$trendMethod]->getGoodnessOfFit();
                 }
                 if ($trendType != self::TREND_BEST_FIT_NO_POLY) {
-                    foreach (self::$_trendTypePolyOrders as $trendMethod) {
+                    foreach (self::$trendTypePolynomialOrders as $trendMethod) {
                         $order = substr($trendMethod, -1);
                         $bestFit[$trendMethod] = new PHPExcel_Polynomial_Best_Fit($order, $yValues, $xValues, $const);
                         if ($bestFit[$trendMethod]->getError()) {
@@ -148,9 +140,8 @@ class trendClass
                 arsort($bestFitValue);
                 $bestFitType = key($bestFitValue);
                 return $bestFit[$bestFitType];
-                break;
             default:
                 return false;
         }
-    }    //    function calculate()
+    }
 }