php-ml/tests/Phpml/Clustering/KMeansTest.php

<?php

declare (strict_types = 1);

namespace tests\Clustering;

use Phpml\Clustering\KMeans;

class KMeansTest extends \PHPUnit_Framework_TestCase
{
    public function testKMeansSamplesClustering()
    {
        $samples = [[1, 1], [8, 7], [1, 2], [7, 8], [2, 1], [8, 9]];

        $kmeans = new KMeans(2);
        $clusters = $kmeans->cluster($samples);

        $this->assertEquals(2, count($clusters));

        foreach ($samples as $index => $sample) {
            if (in_array($sample, $clusters[0]) || in_array($sample, $clusters[1])) {
                unset($samples[$index]);
            }
        }
        $this->assertEquals(0, count($samples));
    }

    public function testKMeansInitializationMethods()
    {
        $samples = [
            [180, 155], [186, 159], [119, 185], [141, 147], [157, 158],
            [176, 122], [194, 160], [113, 193], [190, 148], [152, 154],
            [162, 146], [188, 144], [185, 124], [163, 114], [151, 140],
            [175, 131], [186, 162], [181, 195], [147, 122], [143, 195],
            [171, 119], [117, 165], [169, 121], [159, 160], [159, 112],
            [115, 122], [149, 193], [156, 135], [118, 120], [139, 159],
            [150, 115], [181, 136], [167, 162], [132, 115], [175, 165],
            [110, 147], [175, 118], [113, 145], [130, 162], [195, 179],
            [164, 111], [192, 114], [194, 149], [139, 113], [160, 168],
            [162, 110], [174, 144], [137, 142], [197, 160], [147, 173],
        ];

        $kmeans = new KMeans(4, KMeans::INIT_KMEANS_PLUS_PLUS);
        $clusters = $kmeans->cluster($samples);
        $this->assertEquals(4, count($clusters));

        $kmeans = new KMeans(4, KMeans::INIT_RANDOM);
        $clusters = $kmeans->cluster($samples);
        $this->assertEquals(4, count($clusters));
    }

    /**
     * @expectedException \Phpml\Exception\InvalidArgumentException
     */
    public function testThrowExceptionOnInvalidClusterNumber()
    {
        new KMeans(0);
    }
}