[Summary view] [Print] [Text view]

   1  <?php
   2  
   3  require_once PHPEXCEL_ROOT . 'PHPExcel/Shared/trend/linearBestFitClass.php';
   4  require_once PHPEXCEL_ROOT . 'PHPExcel/Shared/trend/logarithmicBestFitClass.php';
   5  require_once PHPEXCEL_ROOT . 'PHPExcel/Shared/trend/exponentialBestFitClass.php';
   6  require_once PHPEXCEL_ROOT . 'PHPExcel/Shared/trend/powerBestFitClass.php';
   7  require_once PHPEXCEL_ROOT . 'PHPExcel/Shared/trend/polynomialBestFitClass.php';
   8  
   9  /**
  10   * PHPExcel_trendClass
  11   *
  12   * Copyright (c) 2006 - 2015 PHPExcel
  13   *
  14   * This library is free software; you can redistribute it and/or
  15   * modify it under the terms of the GNU Lesser General Public
  16   * License as published by the Free Software Foundation; either
  17   * version 2.1 of the License, or (at your option) any later version.
  18   *
  19   * This library is distributed in the hope that it will be useful,
  20   * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  22   * Lesser General Public License for more details.
  23   *
  24   * You should have received a copy of the GNU Lesser General Public
  25   * License along with this library; if not, write to the Free Software
  26   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
  27   *
  28   * @category   PHPExcel
  29   * @package    PHPExcel_Shared_Trend
  30   * @copyright  Copyright (c) 2006 - 2015 PHPExcel (http://www.codeplex.com/PHPExcel)
  31   * @license    http://www.gnu.org/licenses/old-licenses/lgpl-2.1.txt    LGPL
  32   * @version    ##VERSION##, ##DATE##
  33   */
  34  class trendClass
  35  {
  36      const TREND_LINEAR            = 'Linear';
  37      const TREND_LOGARITHMIC       = 'Logarithmic';
  38      const TREND_EXPONENTIAL       = 'Exponential';
  39      const TREND_POWER             = 'Power';
  40      const TREND_POLYNOMIAL_2      = 'Polynomial_2';
  41      const TREND_POLYNOMIAL_3      = 'Polynomial_3';
  42      const TREND_POLYNOMIAL_4      = 'Polynomial_4';
  43      const TREND_POLYNOMIAL_5      = 'Polynomial_5';
  44      const TREND_POLYNOMIAL_6      = 'Polynomial_6';
  45      const TREND_BEST_FIT          = 'Bestfit';
  46      const TREND_BEST_FIT_NO_POLY  = 'Bestfit_no_Polynomials';
  47  
  48      /**
  49       * Names of the best-fit trend analysis methods
  50       *
  51       * @var string[]
  52       **/
  53      private static $trendTypes = array(
  54          self::TREND_LINEAR,
  55          self::TREND_LOGARITHMIC,
  56          self::TREND_EXPONENTIAL,
  57          self::TREND_POWER
  58      );
  59  
  60      /**
  61       * Names of the best-fit trend polynomial orders
  62       *
  63       * @var string[]
  64       **/
  65      private static $trendTypePolynomialOrders = array(
  66          self::TREND_POLYNOMIAL_2,
  67          self::TREND_POLYNOMIAL_3,
  68          self::TREND_POLYNOMIAL_4,
  69          self::TREND_POLYNOMIAL_5,
  70          self::TREND_POLYNOMIAL_6
  71      );
  72  
  73      /**
  74       * Cached results for each method when trying to identify which provides the best fit
  75       *
  76       * @var PHPExcel_Best_Fit[]
  77       **/
  78      private static $trendCache = array();
  79  
  80  
  81      public static function calculate($trendType = self::TREND_BEST_FIT, $yValues, $xValues = array(), $const = true)
  82      {
  83          //    Calculate number of points in each dataset
  84          $nY = count($yValues);
  85          $nX = count($xValues);
  86  
  87          //    Define X Values if necessary
  88          if ($nX == 0) {
  89              $xValues = range(1, $nY);
  90              $nX = $nY;
  91          } elseif ($nY != $nX) {
  92              //    Ensure both arrays of points are the same size
  93              trigger_error("trend(): Number of elements in coordinate arrays do not match.", E_USER_ERROR);
  94          }
  95  
  96          $key = md5($trendType.$const.serialize($yValues).serialize($xValues));
  97          //    Determine which trend method has been requested
  98          switch ($trendType) {
  99              //    Instantiate and return the class for the requested trend method
 100              case self::TREND_LINEAR:
 101              case self::TREND_LOGARITHMIC:
 102              case self::TREND_EXPONENTIAL:
 103              case self::TREND_POWER:
 104                  if (!isset(self::$trendCache[$key])) {
 105                      $className = 'PHPExcel_'.$trendType.'_Best_Fit';
 106                      self::$trendCache[$key] = new $className($yValues, $xValues, $const);
 107                  }
 108                  return self::$trendCache[$key];
 109              case self::TREND_POLYNOMIAL_2:
 110              case self::TREND_POLYNOMIAL_3:
 111              case self::TREND_POLYNOMIAL_4:
 112              case self::TREND_POLYNOMIAL_5:
 113              case self::TREND_POLYNOMIAL_6:
 114                  if (!isset(self::$trendCache[$key])) {
 115                      $order = substr($trendType, -1);
 116                      self::$trendCache[$key] = new PHPExcel_Polynomial_Best_Fit($order, $yValues, $xValues, $const);
 117                  }
 118                  return self::$trendCache[$key];
 119              case self::TREND_BEST_FIT:
 120              case self::TREND_BEST_FIT_NO_POLY:
 121                  //    If the request is to determine the best fit regression, then we test each trend line in turn
 122                  //    Start by generating an instance of each available trend method
 123                  foreach (self::$trendTypes as $trendMethod) {
 124                      $className = 'PHPExcel_'.$trendMethod.'BestFit';
 125                      $bestFit[$trendMethod] = new $className($yValues, $xValues, $const);
 126                      $bestFitValue[$trendMethod] = $bestFit[$trendMethod]->getGoodnessOfFit();
 127                  }
 128                  if ($trendType != self::TREND_BEST_FIT_NO_POLY) {
 129                      foreach (self::$trendTypePolynomialOrders as $trendMethod) {
 130                          $order = substr($trendMethod, -1);
 131                          $bestFit[$trendMethod] = new PHPExcel_Polynomial_Best_Fit($order, $yValues, $xValues, $const);
 132                          if ($bestFit[$trendMethod]->getError()) {
 133                              unset($bestFit[$trendMethod]);
 134                          } else {
 135                              $bestFitValue[$trendMethod] = $bestFit[$trendMethod]->getGoodnessOfFit();
 136                          }
 137                      }
 138                  }
 139                  //    Determine which of our trend lines is the best fit, and then we return the instance of that trend class
 140                  arsort($bestFitValue);
 141                  $bestFitType = key($bestFitValue);
 142                  return $bestFit[$bestFitType];
 143              default:
 144                  return false;
 145          }
 146      }
 147  }