Code Coverage for /src/SciPhp/NumPhp/VanderTrait.php

1	<?php
2
3	declare(strict_types=1);
4
5	namespace SciPhp\NumPhp;
6
7	use SciPhp\NdArray;
8	use Webmozart\Assert\Assert;
9
10	trait VanderTrait
11	{
12	/**
13	* Generate a Vandermonde matrix.
14	*
15	* @param \SciPhp\NdArray\|array $matrix A 1-dim array.
16	* @param int $num Number of columns for the output.
17	* @return \SciPhp\NdArray A Vandermonde matrix
18	* @throws \InvalidArgumentException
19	* @link http://sciphp.org/numphp.vander Documentation
20	* @api
21	*/
22	final public static function vander($matrix, $num = null): NdArray
23	{
24	static::transform($matrix, true);
25
26	$num = is_null($num)
27	? count($matrix->data)
28	: $num;
29
30	Assert::integer($num);
31	Assert::greaterThan($num, 0);
32	Assert::eq($matrix->ndim, 1, __METHOD__ . '() only accepts vectors.');
33
34	return static::ar(
35	array_map(
36	self::itemVander($num),
37	static::ones(count($matrix->data), $num)->data,
38	$matrix->data
39	)
40	);
41	}
42
43	/**
44	* Apply decreasing power on each row values
45	*
46	* @param int $num Number of wanted columns
47	*/
48	final protected static function itemVander(int $num): callable
49	{
50	return static function ($row, $value) use ($num): array {
51	return array_map(
52	static function($key) use ($value, $num) {
53	return pow($value, $num - $key - 1);
54	},
55	array_keys($row)
56	);
57	};
58	}
59	}