Beatpath

Ruby implementation of the Schulze voting method (https://en.wikipedia.org/wiki/Schulze_method).

Installation

Add this line to your application's Gemfile:

gem "beatpath"

And then execute:

$ bundle

Or install it yourself as:

$ gem install beatpath

Usage

# expected input is an array of arrays
ballots = [
  [55, 34, 56, 76], # each array is a ballot with candidate IDs, in ranked order
                    # so, this ballot implies that they preferred candidate ID 55 first, then
                    # candidate ID 34 second
                    # the candidate ID can be any unique object (symbol, AR record, etc.)
  [55, 56, 76, 34],
  [76, 55, 56, 34],
  [55, 56, 76, 34]
]

winners = Beatpath::Vote.new(ballots).winners
# [55, 56, 76, 34] means that candidate ID 55 is in first place, 56 is in second place, 76 in third, and 34 is last

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/nickelser/beatpath.