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<?php/*** PHPExcel** Copyright (c) 2006 - 2013 PHPExcel** This library is free software; you can redistribute it and/or* modify it under the terms of the GNU Lesser General Public* License as published by the Free Software Foundation; either* version 2.1 of the License, or (at your option) any later version.** This library is distributed in the hope that it will be useful,* but WITHOUT ANY WARRANTY; without even the implied warranty of* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU* Lesser General Public License for more details.** You should have received a copy of the GNU Lesser General Public* License along with this library; if not, write to the Free Software* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA** @category PHPExcel* @package PHPExcel_Shared_Trend* @copyright Copyright (c) 2006 - 2013 PHPExcel (http://www.codeplex.com/PHPExcel)* @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 - 2013 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';/*** 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);/*** 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);/*** Cached results for each method when trying to identify which provides the best fit** @var PHPExcel_Best_Fit[]**/private static $_trendCache = array();public static function calculate($trendType=self::TREND_BEST_FIT, $yValues, $xValues=array(), $const=True) {// Calculate number of points in each dataset$nY = count($yValues);$nX = count($xValues);// Define X Values if necessaryif ($nX == 0) {$xValues = range(1,$nY);$nX = $nY;} elseif ($nY != $nX) {// Ensure both arrays of points are the same sizetrigger_error("trend(): Number of elements in coordinate arrays do not match.", E_USER_ERROR);}$key = md5($trendType.$const.serialize($yValues).serialize($xValues));// Determine which trend method has been requestedswitch ($trendType) {// Instantiate and return the class for the requested trend methodcase self::TREND_LINEAR :case self::TREND_LOGARITHMIC :case self::TREND_EXPONENTIAL :case self::TREND_POWER :if (!isset(self::$_trendCache[$key])) {$className = 'PHPExcel_'.$trendType.'_Best_Fit';self::$_trendCache[$key] = new $className($yValues,$xValues,$const);}return self::$_trendCache[$key];break;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])) {$order = substr($trendType,-1);self::$_trendCache[$key] = new PHPExcel_Polynomial_Best_Fit($order,$yValues,$xValues,$const);}return self::$_trendCache[$key];break;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 methodforeach(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 $trendMethod) {$order = substr($trendMethod,-1);$bestFit[$trendMethod] = new PHPExcel_Polynomial_Best_Fit($order,$yValues,$xValues,$const);if ($bestFit[$trendMethod]->getError()) {unset($bestFit[$trendMethod]);} else {$bestFitValue[$trendMethod] = $bestFit[$trendMethod]->getGoodnessOfFit();}}}// Determine which of our trend lines is the best fit, and then we return the instance of that trend classarsort($bestFitValue);$bestFitType = key($bestFitValue);return $bestFit[$bestFitType];break;default :return false;}} // function calculate()} // class trendClass