PHP Kmean

K-mean clustering algorithm implementation in PHP.

Please also see the FAQ

Installation

You can install the package via composer:

composer require bdelespierre/php-kmeans

Usage

require "vendor/autoload.php";

// prepare 50 points of 2D space to be clustered
$points = [
    [80,55],[86,59],[19,85],[41,47],[57,58],
    [76,22],[94,60],[13,93],[90,48],[52,54],
    [62,46],[88,44],[85,24],[63,14],[51,40],
    [75,31],[86,62],[81,95],[47,22],[43,95],
    [71,19],[17,65],[69,21],[59,60],[59,12],
    [15,22],[49,93],[56,35],[18,20],[39,59],
    [50,15],[81,36],[67,62],[32,15],[75,65],
    [10,47],[75,18],[13,45],[30,62],[95,79],
    [64,11],[92,14],[94,49],[39,13],[60,68],
    [62,10],[74,44],[37,42],[97,60],[47,73],
];

// create a 2-dimentions space
$space = new KMeans\Space(2);

// add points to space
foreach ($points as $i => $coordinates) {
    $space->addPoint($coordinates);
}

// cluster these 50 points in 3 clusters
$clusters = $space->solve(3);

// display the cluster centers and attached points
foreach ($clusters as $num => $cluster) {
    $coordinates = $cluster->getCoordinates();
    printf(
        "Cluster %s [%d,%d]: %d points\n",
        $num,
        $coordinates[0],
        $coordinates[1],
        count($cluster)
    );
}

Note: the example is given with points of a 2D space but it will work with any dimention >1.

Testing

composer test

Changelog

Please see CHANGELOG for more information what has changed recently.

Contributing

Please see CONTRIBUTING for details.

Security

If you discover any security related issues, please email [email protected] instead of using the issue tracker.

Credits

• Benjamin Delespierre
• Ron Cemer
• All Contributors

License

Lesser General Public License (LGPL). Please see License File for more information.

FAQ

How to get coordinates of a point/cluster:

$x = $point[0];
$y = $point[1];

// or

list($x,$y) = $point->getCoordinates();

List all points of a space/cluster:

foreach ($cluster as $point) {
    printf('[%d,%d]', $point[0], $point[1]);
}

Attach data to a point:

$point = $space->addPoint([$x, $y, $z], "user #123");

Retrieve point data:

$data = $space[$point]; // e.g. "user #123"

Watch the algorithm run

Each iteration step can be monitored using a callback function passed to Kmeans\Space::solve:

$clusters = $space->solve(3, function($space, $clusters) {
    static $iterations = 0;

    printf("Iteration: %d\n", ++$iterations);

    foreach ($clusters as $i => $cluster) {
        printf("Cluster %d [%d,%d]: %d points\n", $i, $cluster[0], $cluster[1], count($cluster));
    }
});