Code Coverage for /var/www/html/dev/src/phpOMS/Math/Functions/Fibonacci.php

1	<?php
2	/**
3	* Jingga
4	*
5	* PHP Version 8.1
6	*
7	* @package phpOMS\Math\Functions
8	* @copyright Dennis Eichhorn
9	* @license OMS License 2.0
10	* @version 1.0.0
11	* @link https://jingga.app
12	*/
13	declare(strict_types=1);
14
15	namespace phpOMS\Math\Functions;
16
17	use phpOMS\Math\Number\Numbers;
18
19	/**
20	* Well known functions class.
21	*
22	* @package phpOMS\Math\Functions
23	* @license OMS License 2.0
24	* @link https://jingga.app
25	* @since 1.0.0
26	*/
27	final class Fibonacci
28	{
29	/**
30	* Constructor.
31	*
32	* @since 1.0.0
33	* @codeCoverageIgnore
34	*/
35	private function __construct()
36	{
37	}
38
39	/**
40	* Is Fibonacci number.
41	*
42	* @param int $n Integer
43	*
44	* @return bool
45	*
46	* @since 1.0.0
47	*/
48	public static function isFibonacci(int $n) : bool
49	{
50	return Numbers::isSquare(5 * $n ** 2 + 4) \|\| Numbers::isSquare(5 * $n ** 2 - 4);
51	}
52
53	/**
54	* Get n-th Fibonacci number.
55	*
56	* @param int $n n-th number
57	* @param int $start Start value
58	*
59	* @return int
60	*
61	* @since 1.0.0
62	*/
63	public static function fib(int $n, int $start = 1) : int
64	{
65	if ($n < 3) {
66	return $start;
67	}
68
69	$old1 = $start;
70	$old2 = $start;
71	$fib = 0;
72
73	for ($i = 2; $i < $n; ++$i) {
74	$fib = $old1 + $old2;
75	$old1 = $old2;
76	$old2 = $fib;
77	}
78
79	return $fib;
80	}
81
82	/**
83	* Calculate n-th Fibonacci with binets formula.
84	*
85	* @param int $n n-th number
86	*
87	* @return int
88	*
89	* @since 1.0.0
90	*/
91	public static function binet(int $n) : int
92	{
93	return (int) (((1 + \sqrt(5)) $n - (1 - \sqrt(5)) $n) / (2 ** $n * \sqrt(5)));
94	}
95	}