1<?php 2/** 3 * PHPExcel 4 * 5 * Copyright (c) 2006 - 2014 PHPExcel 6 * 7 * This library is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU Lesser General Public 9 * License as published by the Free Software Foundation; either 10 * version 2.1 of the License, or (at your option) any later version. 11 * 12 * This library is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 15 * Lesser General Public License for more details. 16 * 17 * You should have received a copy of the GNU Lesser General Public 18 * License along with this library; if not, write to the Free Software 19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 20 * 21 * @category PHPExcel 22 * @package PHPExcel_Shared_Trend 23 * @copyright Copyright (c) 2006 - 2014 PHPExcel (http://www.codeplex.com/PHPExcel) 24 * @license http://www.gnu.org/licenses/old-licenses/lgpl-2.1.txt LGPL 25 * @version ##VERSION##, ##DATE## 26 */ 27 28 29require_once PHPEXCEL_ROOT . 'PHPExcel/Shared/trend/linearBestFitClass.php'; 30require_once PHPEXCEL_ROOT . 'PHPExcel/Shared/trend/logarithmicBestFitClass.php'; 31require_once PHPEXCEL_ROOT . 'PHPExcel/Shared/trend/exponentialBestFitClass.php'; 32require_once PHPEXCEL_ROOT . 'PHPExcel/Shared/trend/powerBestFitClass.php'; 33require_once PHPEXCEL_ROOT . 'PHPExcel/Shared/trend/polynomialBestFitClass.php'; 34 35 36/** 37 * PHPExcel_trendClass 38 * 39 * @category PHPExcel 40 * @package PHPExcel_Shared_Trend 41 * @copyright Copyright (c) 2006 - 2014 PHPExcel (http://www.codeplex.com/PHPExcel) 42 */ 43class trendClass 44{ 45 const TREND_LINEAR = 'Linear'; 46 const TREND_LOGARITHMIC = 'Logarithmic'; 47 const TREND_EXPONENTIAL = 'Exponential'; 48 const TREND_POWER = 'Power'; 49 const TREND_POLYNOMIAL_2 = 'Polynomial_2'; 50 const TREND_POLYNOMIAL_3 = 'Polynomial_3'; 51 const TREND_POLYNOMIAL_4 = 'Polynomial_4'; 52 const TREND_POLYNOMIAL_5 = 'Polynomial_5'; 53 const TREND_POLYNOMIAL_6 = 'Polynomial_6'; 54 const TREND_BEST_FIT = 'Bestfit'; 55 const TREND_BEST_FIT_NO_POLY = 'Bestfit_no_Polynomials'; 56 57 /** 58 * Names of the best-fit trend analysis methods 59 * 60 * @var string[] 61 **/ 62 private static $_trendTypes = array( self::TREND_LINEAR, 63 self::TREND_LOGARITHMIC, 64 self::TREND_EXPONENTIAL, 65 self::TREND_POWER 66 ); 67 /** 68 * Names of the best-fit trend polynomial orders 69 * 70 * @var string[] 71 **/ 72 private static $_trendTypePolyOrders = array( self::TREND_POLYNOMIAL_2, 73 self::TREND_POLYNOMIAL_3, 74 self::TREND_POLYNOMIAL_4, 75 self::TREND_POLYNOMIAL_5, 76 self::TREND_POLYNOMIAL_6 77 ); 78 79 /** 80 * Cached results for each method when trying to identify which provides the best fit 81 * 82 * @var PHPExcel_Best_Fit[] 83 **/ 84 private static $_trendCache = array(); 85 86 87 public static function calculate($trendType=self::TREND_BEST_FIT, $yValues, $xValues=array(), $const=True) { 88 // Calculate number of points in each dataset 89 $nY = count($yValues); 90 $nX = count($xValues); 91 92 // Define X Values if necessary 93 if ($nX == 0) { 94 $xValues = range(1,$nY); 95 $nX = $nY; 96 } elseif ($nY != $nX) { 97 // Ensure both arrays of points are the same size 98 trigger_error("trend(): Number of elements in coordinate arrays do not match.", E_USER_ERROR); 99 } 100 101 $key = md5($trendType.$const.serialize($yValues).serialize($xValues)); 102 // Determine which trend method has been requested 103 switch ($trendType) { 104 // Instantiate and return the class for the requested trend method 105 case self::TREND_LINEAR : 106 case self::TREND_LOGARITHMIC : 107 case self::TREND_EXPONENTIAL : 108 case self::TREND_POWER : 109 if (!isset(self::$_trendCache[$key])) { 110 $className = 'PHPExcel_'.$trendType.'_Best_Fit'; 111 self::$_trendCache[$key] = new $className($yValues,$xValues,$const); 112 } 113 return self::$_trendCache[$key]; 114 break; 115 case self::TREND_POLYNOMIAL_2 : 116 case self::TREND_POLYNOMIAL_3 : 117 case self::TREND_POLYNOMIAL_4 : 118 case self::TREND_POLYNOMIAL_5 : 119 case self::TREND_POLYNOMIAL_6 : 120 if (!isset(self::$_trendCache[$key])) { 121 $order = substr($trendType,-1); 122 self::$_trendCache[$key] = new PHPExcel_Polynomial_Best_Fit($order,$yValues,$xValues,$const); 123 } 124 return self::$_trendCache[$key]; 125 break; 126 case self::TREND_BEST_FIT : 127 case self::TREND_BEST_FIT_NO_POLY : 128 // If the request is to determine the best fit regression, then we test each trend line in turn 129 // Start by generating an instance of each available trend method 130 foreach(self::$_trendTypes as $trendMethod) { 131 $className = 'PHPExcel_'.$trendMethod.'BestFit'; 132 $bestFit[$trendMethod] = new $className($yValues,$xValues,$const); 133 $bestFitValue[$trendMethod] = $bestFit[$trendMethod]->getGoodnessOfFit(); 134 } 135 if ($trendType != self::TREND_BEST_FIT_NO_POLY) { 136 foreach(self::$_trendTypePolyOrders as $trendMethod) { 137 $order = substr($trendMethod,-1); 138 $bestFit[$trendMethod] = new PHPExcel_Polynomial_Best_Fit($order,$yValues,$xValues,$const); 139 if ($bestFit[$trendMethod]->getError()) { 140 unset($bestFit[$trendMethod]); 141 } else { 142 $bestFitValue[$trendMethod] = $bestFit[$trendMethod]->getGoodnessOfFit(); 143 } 144 } 145 } 146 // Determine which of our trend lines is the best fit, and then we return the instance of that trend class 147 arsort($bestFitValue); 148 $bestFitType = key($bestFitValue); 149 return $bestFit[$bestFitType]; 150 break; 151 default : 152 return false; 153 } 154 } // function calculate() 155 156} // class trendClass