PHPExcel_Shared_Best_Fit

# Source for file powerBestFitClass.php Documentation is available at powerBestFitClass.php <?php /** * PHPExcel * * Copyright (c) 2006 - 2011 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_Best_Fit * @copyright Copyright (c) 2006 - 2011 PHPExcel (http://www.codeplex.com/PHPExcel) * @license http://www.gnu.org/licenses/old-licenses/lgpl-2.1.txt LGPL * @version 1.7.6, 2011-02-27 */ require_once PHPEXCEL_ROOT . 'PHPExcel/Shared/trend/bestFitClass.php'; /** * PHPExcel_Power_Best_Fit * * @category PHPExcel * @package PHPExcel_Shared_Best_Fit * @copyright Copyright (c) 2006 - 2011 PHPExcel (http://www.codeplex.com/PHPExcel) */ class PHPExcel_Power_Best_Fit extends PHPExcel_Best_Fit { protected $_bestFitType = 'power'; public function getValueOfYForX($xValue) { return $this->getIntersect() * pow(($xValue - $this->_Xoffset),$this->getSlope()); } // function getValueOfYForX() public function getValueOfXForY($yValue) { return pow((($yValue + $this->_Yoffset) / $this->getIntersect()),(1 / $this->getSlope())); } // function getValueOfXForY() public function getEquation($dp=0) { $slope = $this->getSlope($dp); $intersect = $this->getIntersect($dp); return 'Y = '.$intersect.' * X^'.$slope; } // function getEquation() public function getIntersect($dp=0) { if ($dp != 0) { return round(exp($this->_intersect),$dp); } return exp($this->_intersect); } // function getIntersect() private function _power_regression($yValues, $xValues, $const) { foreach($xValues as &$value) { if ($value < 0.0) { $value = 0 - log(abs($value)); } elseif ($value > 0.0) { $value = log($value); } } unset($value); foreach($yValues as &$value) { if ($value < 0.0) { $value = 0 - log(abs($value)); } elseif ($value > 0.0) { $value = log($value); } } unset($value); $this->_leastSquareFit($yValues, $xValues, $const); } // function _power_regression() function __construct($yValues, $xValues=array(), $const=True) { if (parent::__construct($yValues, $xValues) !== False) { $this->_power_regression($yValues, $xValues, $const); } } // function __construct() } // class powerBestFit Documentation generated on Sun, 27 Feb 2011 16:33:29 -0800 by phpDocumentor 1.4.3