/common/libraries/plugin/phpexcel/PHPExcel/Shared/trend/trendClass.php

<?php



require_once PHPEXCEL_ROOT . 'PHPExcel/Shared/trend/linearBestFitClass.php';

require_once PHPEXCEL_ROOT . 'PHPExcel/Shared/trend/logarithmicBestFitClass.php';

require_once PHPEXCEL_ROOT . 'PHPExcel/Shared/trend/exponentialBestFitClass.php';

require_once PHPEXCEL_ROOT . 'PHPExcel/Shared/trend/powerBestFitClass.php';

require_once PHPEXCEL_ROOT . 'PHPExcel/Shared/trend/polynomialBestFitClass.php';



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';

    

    private static $_trendTypes = array(self :: TREND_LINEAR, self :: TREND_LOGARITHMIC, self :: TREND_EXPONENTIAL, 

            self :: TREND_POWER);

    private static $_trendTypePolyOrders = array(self :: TREND_POLYNOMIAL_2, self :: TREND_POLYNOMIAL_3, 

            self :: TREND_POLYNOMIAL_4, self :: TREND_POLYNOMIAL_5, self :: TREND_POLYNOMIAL_6);

    

    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;

        }

    } //	function calculate()




}	//	class trendClass