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.

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Add this line to your application's Gemfile:

gem 'sperm'

And then execute:

$ bundle

Or install it yourself as:

$ gem install sperm


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

This is a shorthand for: { |element| puts element }

You can also use your own source of randomness:,**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 © 2014 Arthur Khashaev. See LICENSE.txt for details.