StandardDeviation::population() - Code Metrics - Inspection of "Implement VarianceThreshold - simple baseline appr..." - php-ai/php-ml - Measure and Improve Code Quality continuously with Scrutinizer

Passed

Pull Request — master (#228)

by Arkadiusz

created 2018-02-10 16:16 UTC

StandardDeviation::population() B

↳ Parent: StandardDeviation

Complexity

Conditions	6
Paths	6

Size

Total Lines	24
Code Lines	13

Duplication

Lines	0
Ratio	0 %

Importance

Changes

Metric	Value
dl	0
loc	24
rs	8.5125
c	0
b	0
f	0
cc	6
eloc	13
nc	6
nop	2

<?php

declare(strict_types=1);

namespace Phpml\Math\Statistic;

use Phpml\Exception\InvalidArgumentException;

class StandardDeviation
{
    /**
     * @param array|float[]|int[] $numbers
     */
    public static function population(array $numbers, bool $sample = true): float
    {
        if (empty($numbers)) {
            throw InvalidArgumentException::arrayCantBeEmpty();
        }

        $n = count($numbers);

        if ($sample && $n === 1) {
            throw InvalidArgumentException::arraySizeToSmall(2);
        }

        $mean = Mean::arithmetic($numbers);
        $carry = 0.0;
        foreach ($numbers as $val) {
            $carry += ($val - $mean) ** 2;
        }

        if ($sample) {
            --$n;
        }

        return sqrt((float) ($carry / $n));
    }

    /**
     * Sum of squares deviations
     * ∑⟮xᵢ - μ⟯²
     *
     * @param array|float[]|int[] $numbers
     */
    public static function sumOfSquares(array $numbers): float
    {
        if (empty($numbers)) {
            throw InvalidArgumentException::arrayCantBeEmpty();
        }

        $mean = Mean::arithmetic($numbers);

        return array_sum(array_map(
            function ($val) use ($mean) {
                return ($val - $mean) ** 2;
            },
            $numbers
        ));
    }
}


1			<?php
2
3			declare(strict_types=1);
4
5			namespace Phpml\Math\Statistic;
6
7			use Phpml\Exception\InvalidArgumentException;
8
9			class StandardDeviation
10			{
11			/**
12			* @param array\|float[]\|int[] $numbers
13			*/
14			public static function population(array $numbers, bool $sample = true): float
15			{
16			if (empty($numbers)) {
17			throw InvalidArgumentException::arrayCantBeEmpty();
18			}
19
20			$n = count($numbers);
21
22			if ($sample && $n === 1) {
23			throw InvalidArgumentException::arraySizeToSmall(2);
24			}
25
26			$mean = Mean::arithmetic($numbers);
27			$carry = 0.0;
28			foreach ($numbers as $val) {
29			$carry += ($val - $mean) ** 2;
30			}
31
32			if ($sample) {
33			--$n;
34			}
35
36			return sqrt((float) ($carry / $n));
37			}
38
39			/**
40			* Sum of squares deviations
41			* ∑⟮xᵢ - μ⟯²
42			*
43			* @param array\|float[]\|int[] $numbers
44			*/
45			public static function sumOfSquares(array $numbers): float
46			{
47			if (empty($numbers)) {
48			throw InvalidArgumentException::arrayCantBeEmpty();
49			}
50
51			$mean = Mean::arithmetic($numbers);
52
53			return array_sum(array_map(
54			function ($val) use ($mean) {
55			return ($val - $mean) ** 2;
56			},
57			$numbers
58			));
59			}
60			}
61

php-ai / php-ml

Pull Request — master (#228)

StandardDeviation::population() B

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