ILIAS  release_5-4 Revision v5.4.26-12-gabc799a52e6
PowerBestFit.php
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1<?php
2
4
5class PowerBestFit extends BestFit
6{
13 protected $bestFitType = 'power';
14
22 public function getValueOfYForX($xValue)
23 {
24 return $this->getIntersect() * ($xValue - $this->xOffset) ** $this->getSlope();
25 }
26
34 public function getValueOfXForY($yValue)
35 {
36 return (($yValue + $this->yOffset) / $this->getIntersect()) ** (1 / $this->getSlope());
37 }
38
46 public function getEquation($dp = 0)
47 {
48 $slope = $this->getSlope($dp);
49 $intersect = $this->getIntersect($dp);
50
51 return 'Y = ' . $intersect . ' * X^' . $slope;
52 }
53
61 public function getIntersect($dp = 0)
62 {
63 if ($dp != 0) {
64 return round(exp($this->intersect), $dp);
65 }
66
67 return exp($this->intersect);
68 }
69
76 private function powerRegression(array $yValues, array $xValues, bool $const): void
77 {
78 $adjustedYValues = array_map(
79 function ($value) {
80 return ($value < 0.0) ? 0 - log(abs($value)) : log($value);
81 },
83 );
84 $adjustedXValues = array_map(
85 function ($value) {
86 return ($value < 0.0) ? 0 - log(abs($value)) : log($value);
87 },
89 );
90
91 $this->leastSquareFit($adjustedYValues, $adjustedXValues, $const);
92 }
93
101 public function __construct($yValues, $xValues = [], $const = true)
102 {
103 parent::__construct($yValues, $xValues);
104
105 if (!$this->error) {
106 $this->powerRegression($yValues, $xValues, (bool) $const);
107 }
108 }
109}
An exception for terminatinating execution or to throw for unit testing.
leastSquareFit(array $yValues, array $xValues, bool $const)
Definition: BestFit.php:405
getSlope($dp=0)
Return the Slope of the line.
Definition: BestFit.php:138
__construct($yValues, $xValues=[], $const=true)
Define the regression and calculate the goodness of fit for a set of X and Y data values.
powerRegression(array $yValues, array $xValues, bool $const)
Execute the regression and calculate the goodness of fit for a set of X and Y data values.
getEquation($dp=0)
Return the Equation of the best-fit line.
getValueOfXForY($yValue)
Return the X-Value for a specified value of Y.
getIntersect($dp=0)
Return the Value of X where it intersects Y = 0.
getValueOfYForX($xValue)
Return the Y-Value for a specified value of X.
error($a_errmsg)
set error message @access public