VarianceThreshold::fit() - Code Metrics - php-ai/php-ml - Measure and Improve Code Quality continuously with Scrutinizer

VarianceThreshold::fit() A
last analyzed 2020-05-15 05:48 UTC

↳ Parent: VarianceThreshold

Complexity

Conditions	3
Paths	3

Size

Total Lines	9
Code Lines	6

Duplication

Lines	0
Ratio	0 %

Importance

Changes	1
Bugs	0	Features	0

Metric	Value
eloc	6
c	1
b	0
f	0
dl	0
loc	9
rs	10
cc	3
nc	3
nop	2

<?php

declare(strict_types=1);

namespace Phpml\FeatureSelection;

use Phpml\Exception\InvalidArgumentException;
use Phpml\Math\Matrix;
use Phpml\Math\Statistic\Variance;
use Phpml\Transformer;

final class VarianceThreshold implements Transformer
{
    /**
     * @var float
     */
    private $threshold;

    /**
     * @var array
     */
    private $variances = [];

    /**
     * @var array
     */
    private $keepColumns = [];

    public function __construct(float $threshold = 0.0)
    {
        if ($threshold < 0) {
            throw new InvalidArgumentException('Threshold can\'t be lower than zero');
        }

        $this->threshold = $threshold;
    }

    public function fit(array $samples, ?array $targets = null): void
    {
        $this->variances = array_map(static function (array $column): float {
            return Variance::population($column);
        }, Matrix::transposeArray($samples));

        foreach ($this->variances as $column => $variance) {
            if ($variance > $this->threshold) {
                $this->keepColumns[$column] = true;
            }
        }
    }

    public function transform(array &$samples, ?array &$targets = null): void
    {
        foreach ($samples as &$sample) {
            $sample = array_values(array_intersect_key($sample, $this->keepColumns));
        }
    }
}


1			<?php
2
3			declare(strict_types=1);
4
5			namespace Phpml\FeatureSelection;
6
7			use Phpml\Exception\InvalidArgumentException;
8			use Phpml\Math\Matrix;
9			use Phpml\Math\Statistic\Variance;
10			use Phpml\Transformer;
11
12			final class VarianceThreshold implements Transformer
13			{
14			/**
15			* @var float
16			*/
17			private $threshold;
18
19			/**
20			* @var array
21			*/
22			private $variances = [];
23
24			/**
25			* @var array
26			*/
27			private $keepColumns = [];
28
29			public function __construct(float $threshold = 0.0)
30			{
31			if ($threshold < 0) {
32			throw new InvalidArgumentException('Threshold can\'t be lower than zero');
33			}
34
35			$this->threshold = $threshold;
36			}
37
38			public function fit(array $samples, ?array $targets = null): void
39			{
40			$this->variances = array_map(static function (array $column): float {
41			return Variance::population($column);
42			}, Matrix::transposeArray($samples));
43
44			foreach ($this->variances as $column => $variance) {
45			if ($variance > $this->threshold) {
46			$this->keepColumns[$column] = true;
47			}
48			}
49			}
50
51			public function transform(array &$samples, ?array &$targets = null): void
52			{
53			foreach ($samples as &$sample) {
54			$sample = array_values(array_intersect_key($sample, $this->keepColumns));
55			}
56			}
57			}
58

php-ai / php-ml

VarianceThreshold::fit() A last analyzed 2020-05-15 05:48 UTC

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VarianceThreshold::fit() A
last analyzed 2020-05-15 05:48 UTC