108 lines
4.0 KiB
PHP
108 lines
4.0 KiB
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
|