Module: Equalshares::Statistics

Defined in:
lib/equalshares/statistics.rb

Overview

Outcome statistics. Faithful port of gatherOutcomeStatistics() in js/methodOfEqualSharesWorker.js.

Class Method Summary collapse

Class Method Details

.gather(voter_ids, cost, approvers, winners) ⇒ Object

cost is the numeric cost map (Float or Rational).



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# File 'lib/equalshares/statistics.rb', line 10

def gather(voter_ids, cost, approvers, winners)
  n = voter_ids.length
  total_cost = winners.sum { |c| cost[c] }
  avg_approved_projects = winners.sum { |c| approvers[c].length }.to_f / n
  avg_cost_of_winning_approved = winners.sum { |c| approvers[c].length * cost[c] }.to_f / n

  voter_utility = Hash.new(0)
  winners.each do |c|
    approvers[c].each { |i| voter_utility[i] += 1 }
  end

  # For each r, how many voters approve exactly r winning projects?
  utility_distribution = {}
  (0..winners.length).each { |util| utility_distribution[util] = 0 }
  voter_ids.each { |i| utility_distribution[voter_utility[i]] += 1 }

  {
    total_cost: total_cost,
    avg_approved_projects: avg_approved_projects,
    avg_cost_of_winning_approved_projects: avg_cost_of_winning_approved,
    utility_distribution: utility_distribution
  }
end