README

NGT - high-speed approximate nearest neighbors - for PHP

Installation

Run:

composer require ankane/ngt

Add scripts to composer.json to download the shared library:

 "scripts": { "post-install-cmd": "Ngt\\Vendor::check", "post-update-cmd": "Ngt\\Vendor::check" }

And run:

composer install

On Mac, also install OpenMP:

brew install libomp

NGT is not available for Windows

Getting Started

Prep your data

$objects = [ [1, 1, 2, 1], [5, 4, 6, 5], [1, 2, 1, 2] ];

Create an index

$index = new Ngt\Index($dimensions);

Insert objects

$index->batchInsert($objects);

Search the index

$index->search($query, size: 3);

Save the index

$index->save($path);

Load an index

$index = Ngt\Index::load($path);

Get an object by id

$index->object($id);

Insert a single object

$index->insert($object);

Remove an object by id

$index->remove($id);

Build the index

$index->buildIndex();

Full Example

$dim = 10; $objects = []; for ($i = 0; $i < 100; $i++) { $object = []; for ($j = 0; $j < $dim; $j++) { $object[] = rand(0, 100); } $objects[] = $object; } $index = new Ngt\Index($dim); $index->batchInsert($objects); $query = $objects[0]; $result = $index->search($query, size: 3); foreach ($result as $res) { print($res['id'] . ', ' . $res['distance'] . "\n"); }

Index Options

Defaults shown below

use Ngt\DistanceType; use Ngt\ObjectType; new Ngt\Index( $dimensions, edgeSizeForCreation: 10, edgeSizeForSearch: 40, distanceType: DistanceType::L2, // L1, L2, Hamming, Angle, Cosine, NormalizedAngle, NormalizedCosine, Jaccard objectType: ObjectType::Float // Float, Float16, Integer );

Credits

This library is modeled after NGT’s Python API.

History

View the changelog

Contributing

Everyone is encouraged to help improve this project. Here are a few ways you can help:

• Report bugs
• Fix bugs and submit pull requests
• Write, clarify, or fix documentation
• Suggest or add new features

To get started with development:

git clone https://github.com/ankane/ngt-php.git cd ngt-php composer install composer test