ILIAS  release_5-2 Revision v5.2.25-18-g3f80b82851
logarithmicBestFitClass.php
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1 <?php
29 require_once(PHPEXCEL_ROOT . 'PHPExcel/Shared/trend/bestFitClass.php');
30 
31 
40 {
47  protected $_bestFitType = 'logarithmic';
48 
49 
56  public function getValueOfYForX($xValue) {
57  return $this->getIntersect() + $this->getSlope() * log($xValue - $this->_Xoffset);
58  } // function getValueOfYForX()
59 
60 
67  public function getValueOfXForY($yValue) {
68  return exp(($yValue - $this->getIntersect()) / $this->getSlope());
69  } // function getValueOfXForY()
70 
71 
78  public function getEquation($dp=0) {
79  $slope = $this->getSlope($dp);
80  $intersect = $this->getIntersect($dp);
81 
82  return 'Y = '.$intersect.' + '.$slope.' * log(X)';
83  } // function getEquation()
84 
85 
93  private function _logarithmic_regression($yValues, $xValues, $const) {
94  foreach($xValues as &$value) {
95  if ($value < 0.0) {
96  $value = 0 - log(abs($value));
97  } elseif ($value > 0.0) {
98  $value = log($value);
99  }
100  }
101  unset($value);
102 
103  $this->_leastSquareFit($yValues, $xValues, $const);
104  } // function _logarithmic_regression()
105 
106 
114  function __construct($yValues, $xValues=array(), $const=True) {
115  if (parent::__construct($yValues, $xValues) !== False) {
116  $this->_logarithmic_regression($yValues, $xValues, $const);
117  }
118  } // function __construct()
119 
120 } // class logarithmicBestFit
getIntersect($dp=0)
Return the Value of X where it intersects Y = 0.
getValueOfXForY($yValue)
Return the X-Value for a specified value of Y.
getValueOfYForX($xValue)
Return the Y-Value for a specified value of X.
getEquation($dp=0)
Return the Equation of the best-fit line.
getSlope($dp=0)
Return the Slope of the line.
_logarithmic_regression($yValues, $xValues, $const)
Execute the regression and calculate the goodness of fit for a set of X and Y data values...
__construct($yValues, $xValues=array(), $const=True)
Define the regression and calculate the goodness of fit for a set of X and Y data values...
Create styles array
The data for the language used.
_leastSquareFit($yValues, $xValues, $const)