Annoy.rb provides Ruby bindings for the Annoy (Approximate Nearest Neighbors Oh Yeah).

Add this line to your application's Gemfile:

gem 'annoy-rb'

And then execute:

$ bundle install

Or install it yourself as:

$ gem install annoy-rb

Note: Annoy.rb does not require the installation of another external library.

• Annoy.rb API Documentation

require 'annoy'

f = 40 # length of item vector that will be indexed.
t = Annoy::AnnoyIndex.new(n_features: f, metric: 'angular')

1000.times do |i|
  v = Array.new(f) { rand }
  t.add_item(i, v)
end

t.build(10) # 10 trees.
t.save('test.ann')

u = Annoy::AnnoyIndex.new(n_features: f, metric: 'angular')
u.load('test.ann')
p u.get_nns_by_item(0, 100) # will find the 100 nearest neighbors.

The gem is available as open source under the terms of the Apache-2.0 License.

Bug reports and pull requests are welcome on GitHub at https://github.com/yoshoku/annoy.rb. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the code of conduct.