class trendClass in Loft Data Grids 7.2

PHPExcel_trendClass

@category PHPExcel @package PHPExcel_Shared_Trend @copyright Copyright (c) 2006 - 2014 PHPExcel (http://www.codeplex.com/PHPExcel)

Hierarchy

• class \trendClass

File

vendor/phpoffice/phpexcel/Classes/PHPExcel/Shared/trend/trendClass.php, line 43

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 necessary
    if ($nX == 0) {
      $xValues = range(1, $nY);
      $nX = $nY;
    }
    elseif ($nY != $nX) {

      //	Ensure both arrays of points are the same size
      trigger_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 requested
    switch ($trendType) {

      //	Instantiate and return the class for the requested trend method
      case 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 method
        foreach (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 class
        arsort($bestFitValue);
        $bestFitType = key($bestFitValue);
        return $bestFit[$bestFitType];
        break;
      default:
        return false;
    }
  }

}

Members

Name	Modifiers	Type	Description	Overrides
trendClass::$_trendCache	private static	property	* Cached results for each method when trying to identify which provides the best fit * * *
trendClass::$_trendTypePolyOrders	private static	property	* Names of the best-fit trend polynomial orders * * *
trendClass::$_trendTypes	private static	property	* Names of the best-fit trend analysis methods * * *
trendClass::calculate	public static	function
trendClass::TREND_BEST_FIT		constant
trendClass::TREND_BEST_FIT_NO_POLY		constant
trendClass::TREND_EXPONENTIAL		constant
trendClass::TREND_LINEAR		constant
trendClass::TREND_LOGARITHMIC		constant
trendClass::TREND_POLYNOMIAL_2		constant
trendClass::TREND_POLYNOMIAL_3		constant
trendClass::TREND_POLYNOMIAL_4		constant
trendClass::TREND_POLYNOMIAL_5		constant
trendClass::TREND_POLYNOMIAL_6		constant
trendClass::TREND_POWER		constant