tablepress / libraries / vendor / PhpSpreadsheet / Shared / Trend / Trend.php

Trend.php in TablePress – Tables in WordPress made easy 3.4, at libraries/vendor/PhpSpreadsheet/Shared/Trend/Trend.php

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1	<?php
2
3	namespace TablePress\PhpOffice\PhpSpreadsheet\Shared\Trend;
4
5	use TablePress\PhpOffice\PhpSpreadsheet\Exception as SpreadsheetException;
6
7	class Trend
8	{
9	const TREND_LINEAR = 'Linear';
10	const TREND_LOGARITHMIC = 'Logarithmic';
11	const TREND_EXPONENTIAL = 'Exponential';
12	const TREND_POWER = 'Power';
13	const TREND_POLYNOMIAL_2 = 'Polynomial_2';
14	const TREND_POLYNOMIAL_3 = 'Polynomial_3';
15	const TREND_POLYNOMIAL_4 = 'Polynomial_4';
16	const TREND_POLYNOMIAL_5 = 'Polynomial_5';
17	const TREND_POLYNOMIAL_6 = 'Polynomial_6';
18	const TREND_BEST_FIT = 'Bestfit';
19	const TREND_BEST_FIT_NO_POLY = 'Bestfit_no_Polynomials';
20
21	/**
22	* Names of the best-fit Trend analysis methods.
23	*/
24	private const TREND_TYPES = [
25	self::TREND_LINEAR,
26	self::TREND_LOGARITHMIC,
27	self::TREND_EXPONENTIAL,
28	self::TREND_POWER,
29	];
30
31	/**
32	* Names of the best-fit Trend polynomial orders.
33	*
34	* @var string[]
35	*/
36	private static array $trendTypePolynomialOrders = [
37	self::TREND_POLYNOMIAL_2,
38	self::TREND_POLYNOMIAL_3,
39	self::TREND_POLYNOMIAL_4,
40	self::TREND_POLYNOMIAL_5,
41	self::TREND_POLYNOMIAL_6,
42	];
43
44	/**
45	* Cached results for each method when trying to identify which provides the best fit.
46	*
47	* @var BestFit[]
48	*/
49	private static array $trendCache = [];
50
51	/**
52	* @param mixed[] $yValues
53	* @param mixed[] $xValues
54	*/
55	public static function calculate(string $trendType = self::TREND_BEST_FIT, array $yValues = [], array $xValues = [], bool $const = true): BestFit
56	{
57	// Calculate number of points in each dataset
58	/** @var float[] $xValues */
59	$nY = count($yValues);
60	/** @var float[] $xValues */
61	$nX = count($xValues);
62
63	// Define X Values if necessary
64	if ($nX === 0) {
65	$xValues = range(1, $nY);
66	} elseif ($nY !== $nX) {
67	// Ensure both arrays of points are the same size
68	throw new SpreadsheetException('Trend(): Number of elements in coordinate arrays do not match.');
69	}
70
71	$key = md5($trendType . $const . serialize($yValues) . serialize($xValues));
72	// Determine which Trend method has been requested
73	switch ($trendType) {
74	// Instantiate and return the class for the requested Trend method
75	case self::TREND_LINEAR:
76	case self::TREND_LOGARITHMIC:
77	case self::TREND_EXPONENTIAL:
78	case self::TREND_POWER:
79	if (!isset(self::$trendCache[$key])) {
80	/** @var float[] $yValues */
81	$className = '\TablePress\PhpOffice\PhpSpreadsheet\Shared\Trend\\' . $trendType . 'BestFit';
82	/** @var float[] $xValues */
83	self::$trendCache[$key] = new $className($yValues, $xValues, $const);
84	}
85
86	return self::$trendCache[$key];
87	case self::TREND_POLYNOMIAL_2:
88	case self::TREND_POLYNOMIAL_3:
89	case self::TREND_POLYNOMIAL_4:
90	case self::TREND_POLYNOMIAL_5:
91	case self::TREND_POLYNOMIAL_6:
92	if (!isset(self::$trendCache[$key])) {
93	$order = (int) substr($trendType, -1);
94	/** @var float[] $yValues */
95	self::$trendCache[$key] = new PolynomialBestFit($order, $yValues, $xValues);
96	}
97
98	return self::$trendCache[$key];
99	case self::TREND_BEST_FIT:
100	case self::TREND_BEST_FIT_NO_POLY:
101	// If the request is to determine the best fit regression, then we test each Trend line in turn
102	// Start by generating an instance of each available Trend method
103	/** @var float[] $yValues */
104	$bestFit = [];
105	/** @var float[] $xValues */
106	$bestFitValue = [];
107	foreach (self::TREND_TYPES as $trendMethod) {
108	$className = '\TablePress\PhpOffice\PhpSpreadsheet\Shared\Trend\\' . $trendMethod . 'BestFit';
109	$bestFit[$trendMethod] = new $className($yValues, $xValues, $const);
110	$bestFitValue[$trendMethod] = $bestFit[$trendMethod]->getGoodnessOfFit();
111	}
112	if ($trendType !== self::TREND_BEST_FIT_NO_POLY) {
113	foreach (self::$trendTypePolynomialOrders as $trendMethod) {
114	$order = (int) substr($trendMethod, -1);
115	$bestFit[$trendMethod] = new PolynomialBestFit($order, $yValues, $xValues);
116	if ($bestFit[$trendMethod]->getError()) {
117	unset($bestFit[$trendMethod]);
118	} else {
119	$bestFitValue[$trendMethod] = $bestFit[$trendMethod]->getGoodnessOfFit();
120	}
121	}
122	}
123	// Determine which of our Trend lines is the best fit, and then we return the instance of that Trend class
124	arsort($bestFitValue);
125	$bestFitType = key($bestFitValue);
126
127	return $bestFit[$bestFitType];
128	default:
129	throw new SpreadsheetException("Unknown trend type $trendType");
130	}
131	}
132	}
133