Stupendous Permutations

Sperm is a random permutations generator based on the ideas of group theory that allows you to generate very large permutations without extra memory consumption.

Gem Version Build Status Code Climate Coverage Status

Installation

Add this line to your application's Gemfile:

gem 'sperm'

And then execute:

$ bundle

Or install it yourself as:

$ gem install sperm

Usage

Sperm.rand(5).each { |element| puts element }

This is a shorthand for:

Sperm::RandomPermutations.new(5).rand.each { |element| puts element }

You can also use your own source of randomness:

Sperm::RandomPermutations.new(5, Random.new(42))
Sperm::RandomPermutations.new(10**8, SecureRandom)

How it works

Computational complexity

Operation Time complexity Space complexity
Initialization O(n/ϕ(n) · log(n)) O(1)
Generation of next element O(1) O(1)

Copyright

Copyright © 2014 Arthur Khashaev. See LICENSE.txt for details.