PHPExcel_Shared_Best_Fit

# Source for file polynomialBestFitClass.php Documentation is available at polynomialBestFitClass.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'; require_once PHPEXCEL_ROOT . 'PHPExcel/Shared/JAMA/Matrix.php'; /** * PHPExcel_Polynomial_Best_Fit * * @category PHPExcel * @package PHPExcel_Shared_Best_Fit * @copyright Copyright (c) 2006 - 2011 PHPExcel (http://www.codeplex.com/PHPExcel) */ class PHPExcel_Polynomial_Best_Fit extends PHPExcel_Best_Fit { protected $_bestFitType = 'polynomial'; protected $_order = 0; public function getOrder() { return $this->_order; } // function getOrder() public function getValueOfYForX($xValue) { $retVal = $this->getIntersect(); $slope = $this->getSlope(); foreach($slope as $key => $value) { if ($value != 0.0) { $retVal += $value * pow($xValue, $key + 1); } } return $retVal; } // function getValueOfYForX() public function getValueOfXForY($yValue) { return ($yValue - $this->getIntersect()) / $this->getSlope(); } // function getValueOfXForY() public function getEquation($dp=0) { $slope = $this->getSlope($dp); $intersect = $this->getIntersect($dp); $equation = 'Y = '.$intersect; foreach($slope as $key => $value) { if ($value != 0.0) { $equation .= ' + '.$value.' * X'; if ($key > 0) { $equation .= '^'.($key + 1); } } } return $equation; } // function getEquation() public function getSlope($dp=0) { if ($dp != 0) { $coefficients = array(); foreach($this->_slope as $coefficient) { $coefficients[] = round($coefficient,$dp); } return $coefficients; } return $this->_slope; } // function getSlope() public function getCoefficients($dp=0) { return array_merge(array($this->getIntersect($dp)),$this->getSlope($dp)); } // function getCoefficients() private function _polynomial_regression($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) { $xy_sum += $xValues[$i] * $yValues[$i]; $xx_sum += $xValues[$i] * $xValues[$i]; $yy_sum += $yValues[$i] * $yValues[$i]; } /* * This routine uses logic from the PHP port of polyfit version 0.1 * written by Michael Bommarito and Paul Meagher * * The function fits a polynomial function of order $order through * a series of x-y data points using least squares. * */ for ($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) { $B[$i] = array($yValues[$i]); } $matrixA = new Matrix($A); $matrixB = new Matrix($B); $C = $matrixA->solve($matrixB); $coefficients = array(); for($i = 0; $i < $C->m; ++$i) { $r = $C->get($i, 0); if (abs($r) <= pow(10, -9)) { $r = 0; } $coefficients[] = $r; } $this->_intersect = array_shift($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); } } // function _polynomial_regression() 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, $const); if (($this->getGoodnessOfFit() < 0.0) || ($this->getGoodnessOfFit() > 1.0)) { $this->_error = True; } } else { $this->_error = True; } } } // function __construct() } // class polynomialBestFit Documentation generated on Sun, 27 Feb 2011 16:33:28 -0800 by phpDocumentor 1.4.3