wpdatatables / lib / phpoffice / phpspreadsheet / src / PhpSpreadsheet / Calculation / Engineering / Erf.php

Erf.php in wpDataTables – WordPress Data Table, Dynamic Tables & Table Charts Plugin 6.5.1.7, at lib/phpoffice/phpspreadsheet/src/PhpSpreadsheet/Calculation/Engineering/Erf.php

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1	<?php
2
3	namespace PhpOffice\PhpSpreadsheet\Calculation\Engineering;
4
5	use PhpOffice\PhpSpreadsheet\Calculation\ArrayEnabled;
6	use PhpOffice\PhpSpreadsheet\Calculation\Functions;
7	use PhpOffice\PhpSpreadsheet\Calculation\Information\ExcelError;
8
9	class Erf
10	{
11	use ArrayEnabled;
12
13	private const TWO_SQRT_PI = 1.128379167095512574;
14
15	/**
16	* ERF.
17	*
18	* Returns the error function integrated between the lower and upper bound arguments.
19	*
20	* Note: In Excel 2007 or earlier, if you input a negative value for the upper or lower bound arguments,
21	* the function would return a #NUM! error. However, in Excel 2010, the function algorithm was
22	* improved, so that it can now calculate the function for both positive and negative ranges.
23	* PhpSpreadsheet follows Excel 2010 behaviour, and accepts negative arguments.
24	*
25	* Excel Function:
26	* ERF(lower[,upper])
27	*
28	* @param mixed $lower Lower bound float for integrating ERF
29	* Or can be an array of values
30	* @param mixed $upper Upper bound float for integrating ERF.
31	* If omitted, ERF integrates between zero and lower_limit
32	* Or can be an array of values
33	*
34	* @return array\|float\|string
35	* If an array of numbers is passed as an argument, then the returned result will also be an array
36	* with the same dimensions
37	*/
38	public static function ERF($lower, $upper = null)
39	{
40	if (is_array($lower) \|\| is_array($upper)) {
41	return self::evaluateArrayArguments([self::class, __FUNCTION__], $lower, $upper);
42	}
43
44	if (is_numeric($lower)) {
45	if ($upper === null) {
46	return self::erfValue($lower);
47	}
48	if (is_numeric($upper)) {
49	return self::erfValue($upper) - self::erfValue($lower);
50	}
51	}
52
53	return ExcelError::VALUE();
54	}
55
56	/**
57	* ERFPRECISE.
58	*
59	* Returns the error function integrated between the lower and upper bound arguments.
60	*
61	* Excel Function:
62	* ERF.PRECISE(limit)
63	*
64	* @param mixed $limit Float bound for integrating ERF, other bound is zero
65	* Or can be an array of values
66	*
67	* @return array\|float\|string
68	* If an array of numbers is passed as an argument, then the returned result will also be an array
69	* with the same dimensions
70	*/
71	public static function ERFPRECISE($limit)
72	{
73	if (is_array($limit)) {
74	return self::evaluateSingleArgumentArray([self::class, __FUNCTION__], $limit);
75	}
76
77	return self::ERF($limit);
78	}
79
80	/**
81	* Method to calculate the erf value.
82	*
83	* @param float\|int\|string $value
84	*
85	* @return float
86	*/
87	public static function erfValue($value)
88	{
89	$value = (float) $value;
90	if (abs($value) > 2.2) {
91	return 1 - ErfC::ERFC($value);
92	}
93	$sum = $term = $value;
94	$xsqr = ($value * $value);
95	$j = 1;
96	do {
97	$term *= $xsqr / $j;
98	$sum -= $term / (2 * $j + 1);
99	++$j;
100	$term *= $xsqr / $j;
101	$sum += $term / (2 * $j + 1);
102	++$j;
103	if ($sum == 0.0) {
104	break;
105	}
106	} while (abs($term / $sum) > Functions::PRECISION);
107
108	return self::TWO_SQRT_PI * $sum;
109	}
110	}
111