From: <mako@atdot.cc>
Date: Thu, 9 Aug 2007 21:38:17 +0000 (-0400)
Subject: upgraded to latest version of rubyvote in svn
X-Git-Url: https://projects.mako.cc/source/selectricity/commitdiff_plain/6dfbfbec4b0d01138c272649d668c5a872706a5c?ds=sidebyside

upgraded to latest version of rubyvote in svn
---

diff --git a/lib/rubyvote.rb b/lib/rubyvote.rb
index 1585389..2f11561 100644
--- a/lib/rubyvote.rb
+++ b/lib/rubyvote.rb
@@ -3,6 +3,6 @@
 require File.dirname(__FILE__) + '/rubyvote/election'
 require File.dirname(__FILE__) + '/rubyvote/condorcet'
 require File.dirname(__FILE__) + '/rubyvote/positional'
-require File.dirname(__FILE__) + '/rubyvote/runoff'
+require File.dirname(__FILE__) + '/rubyvote/irv'
 require File.dirname(__FILE__) + '/rubyvote/range'
 
diff --git a/lib/rubyvote/condorcet.rb b/lib/rubyvote/condorcet.rb
index 95663d4..65c664d 100644
--- a/lib/rubyvote/condorcet.rb
+++ b/lib/rubyvote/condorcet.rb
@@ -33,53 +33,106 @@
 
 class CondorcetVote < ElectionVote
 
-  def tally_vote(vote=nil)
+  attr_accessor :results
+
+  def initialize(votes=nil)
+    unless defined?(@candidates)
+      @candidates = Array.new
+      votes.each do |vote_row|
+        vote_row = vote_row.flatten if vote_row.class == Array
+        vote_row.each do |vote| 
+          @candidates << vote unless @candidates.include?(vote)
+        end
+      end
+    end
+    super(votes)
+    @results = Array.new
+  end
 
-    vote.each_with_index do |winner, index|
-      # only run through this if this *is* preferred to something
-      break if vote.length - 1 == index
-      losers = vote.last( vote.length - index )
+  def tally_vote(vote=nil)
 
-      losers.each do |loser|
-        next if winner == loser
+    vote.each_with_index do |winners, index|
+      if vote.flatten.length < @candidates.length
+        implied_losers = @candidates.select { |c| not vote.flatten.include?(c) }
+        vote.push(implied_losers)
+      end
+      if vote.length - 1 == index
+        losers = []
+      else
+        losers = vote.flatten.last( vote.flatten.length - index - 1)
+      end
 
-        @votes[winner] = Hash.new unless @votes.has_key?(winner)
-        @votes[loser] = Hash.new unless @votes.has_key?(loser)
+      losers.each do |place|
+        place = [place] unless place.class == Array
+        place.each do |loser|
+          
+          winners = [winners] unless winners.class == Array
+          next if winners.include?(loser)
+          winners.each do |winner|
+            @votes[winner] = Hash.new unless @votes.has_key?(winner)
+            @votes[loser] = Hash.new unless @votes.has_key?(loser)
+
+            if @votes[winner].has_key?(loser)
+              @votes[winner][loser] += 1
+            else
+              @votes[winner][loser] = 1
+            end
 
-        if @votes[winner].has_key?(loser)
-          @votes[winner][loser] += 1
-        else
-          @votes[winner][loser] = 1
+            # make sure we have a comparable object
+            @votes[loser][winner] = 0 unless @votes[loser].has_key?( winner )
+          end
         end
-
-        # make sure we have a comparable object
-        @votes[loser][winner] = 0 unless @votes[loser].has_key?( winner )
-
-        @candidates << loser unless @candidates.include?( loser )
       end
+    end
+  end
 
-      @candidates << winner unless @candidates.include?( winner )
+  def results
+    if @results.size < 2 && (not @candidates.empty?)
+      tabulate
     end
+    @results
+  end
+
+  def result
+    find_only_winner unless @winner
+    @winner
   end
 
   protected
+
   def verify_vote(vote=nil)
     vote.instance_of?( Array ) and
       vote == vote.uniq
   end
-  
+
+  def tabulate
+    find_only_winner unless @winner
+    until @candidates.empty? 
+      aResult = resultFactory( self )
+      @results << aResult.winners
+      filter_out(aResult)
+    end
+  end
+
+  def find_only_winner
+    @winner = resultFactory( self )
+    @results << @winner.winners
+    filter_out(@winner)
+  end
+
 end
 
 class PureCondorcetVote < CondorcetVote
-  def result
-    PureCondorcetResult.new( self )
+  def resultFactory(init)
+    PureCondorcetResult.new(init)
   end
 end
 
 class CloneproofSSDVote < CondorcetVote
-  def result
-    CloneproofSSDResult.new( self )
+  def resultFactory(init)
+    CloneproofSSDResult.new(init)
   end
+
 end
 
 
@@ -98,11 +151,14 @@ class CondorcetResult < ElectionResult
     super(voteobj)
   end
 
+  protected
+
   def defeats(candidates=nil, votes=nil)
     candidates = @election.candidates unless candidates
     votes = @election.votes unless votes
 
     defeats = Array.new
+    candidates = [candidates] unless candidates.class == Array
     candidates.each do |candidate|
       candidates.each do |challenger|
         next if candidate == challenger
@@ -124,6 +180,7 @@ class PureCondorcetResult < CondorcetResult
   end
 
   protected
+
   def condorcet
     votes = @election.votes
     candidates = @election.candidates
@@ -138,11 +195,18 @@ class PureCondorcetResult < CondorcetResult
       victors[winner] << loser
     end
 
-    winners = @election.candidates.find_all do |candidate|
-        victors[candidate].length == @election.candidates.length - 1
+    victory_margin = 1
+    while true
+      winners = @election.candidates.find_all do |candidate|
+        victors[candidate].length == @election.candidates.length - victory_margin
+      end
+      if winners.length > 0
+        @winners = winners
+        return @winners
+      else
+        victory_margin += 1
+      end
     end
-
-    @winners = winners if winners.length == 1
   end
 end
 
@@ -153,6 +217,7 @@ class CloneproofSSDResult < CondorcetResult
   end
 
   protected
+
   def cpssd
     votes = @election.votes
     candidates = *@election.candidates
@@ -173,15 +238,22 @@ class CloneproofSSDResult < CondorcetResult
 
       # see the array with the standard defeats
       transitive_defeats = self.defeats(candidates, votes)
+      defeats_hash = Hash.new
+      transitive_defeats.each { |td| defeats_hash[td] = 1 }
 
+      candidates = [candidates] unless candidates.class == Array
       candidates.each do |cand1|
         candidates.each do |cand2|
-          candidates.each do |cand3|
-            if transitive_defeats.include?( [ cand2, cand1 ] ) and
-                transitive_defeats.include?( [ cand1, cand3 ] ) and
-                not transitive_defeats.include?( [ cand2, cand3 ] ) and
-                not cand2 == cand3
-              transitive_defeats << [ cand2, cand3 ]
+          unless cand1 == cand2
+            candidates.each do |cand3|
+              if not cand2 == cand3 and 
+                  not cand1 == cand3 and 
+                  defeats_hash[[cand2, cand1]] and
+                  defeats_hash[[cand1, cand3]] and
+                  not defeats_hash[[cand2, cand3]] 
+                transitive_defeats << [cand2, cand3]
+                defeats_hash[[cand2, cand3]] = 1
+              end
             end
           end
         end
diff --git a/lib/rubyvote/election.rb b/lib/rubyvote/election.rb
index fc61840..3d816a8 100644
--- a/lib/rubyvote/election.rb
+++ b/lib/rubyvote/election.rb
@@ -61,6 +61,11 @@ class ElectionVote
   def tally_vote
     self.verify_vote(vote)
   end
+
+  def filter_out(winner)
+    @candidates.delete_if {|x| winner.winners.include?(x)}
+  end
+
 end
 
 class PluralityVote < ElectionVote
@@ -70,7 +75,7 @@ class PluralityVote < ElectionVote
   
   protected
   def verify_vote(vote=nil)
-    vote ? true : false
+    vote.instance_of?( String )
   end
 
   def tally_vote(candidate)
diff --git a/lib/rubyvote/irv.rb b/lib/rubyvote/irv.rb
new file mode 100644
index 0000000..3851738
--- /dev/null
+++ b/lib/rubyvote/irv.rb
@@ -0,0 +1,225 @@
+class InstantRunoffVote < ElectionVote
+  def initialize(votes=nil)
+    @candidates = Array.new
+    votes.each do |vote|
+      @candidates = vote.uniq if vote.uniq.length > candidates.length
+    end
+    super(votes)
+    @candidates.each do |candidate|
+      @votes[candidate] = [0, Hash.new] unless @votes.has_key?(candidate)
+    end
+  end
+
+  def result(params={})
+    InstantRunoffResult.new(self, params)
+  end
+  
+  protected
+  def tally_vote(vote)
+    votecopy = vote.dup
+    candidate = votecopy.shift
+    votes[candidate] = [0, Hash.new] unless votes.has_key?(candidate)
+    votes[candidate][0] += 1
+    if votes[candidate][1].has_key?(votecopy)
+      votes[candidate][1][votecopy] += 1
+    else
+      votes[candidate][1][votecopy] = 1
+    end
+  end
+
+  def verify_vote(vote=nil)
+    vote.instance_of?( Array ) and
+      vote == vote.uniq
+  end
+end
+
+class InstantRunoffLogicVote < InstantRunoffVote
+  def result(params={})
+    InstantRunoffLogicResult.new(self, params)
+  end
+end
+
+class InstantRunoffFirstRoundVote < InstantRunoffVote
+  def result(params={})
+    InstantRunoffFirstRoundResult.new(self, params)
+  end
+end
+
+class InstantRunoffAllVote < InstantRunoffVote
+  def result(params={})
+    InstantRunoffAllResult.new(self, params)
+  end
+end
+
+class InstantRunoffRandomVote < InstantRunoffVote
+  def result(params={})
+    InstantRunoffRandomResult.new(self, params)
+  end
+end
+
+class InstantRunoffResult < ElectionResult
+  attr_reader :ranked_candidates
+
+  def initialize(voteobj=nil, params={})
+    unless voteobj and voteobj.kind_of?( InstantRunoffVote )
+      raise ArgumentError, "You must pass an InstantRunoffVote array.", caller
+    end
+    super(voteobj)
+
+    votes = @election.votes.clone
+    candidates = @election.candidates
+    votes_sum = votes.inject(0) {|n, value| n + value[1][0]}
+    @majority = votes_sum/2 + 1
+    @ranked_candidates = Array.new()
+    ranked_candidates = Array.new()
+    losers = Array.new()
+
+    if params.has_key?('candidate_count')
+      apply_candidate_count(votes, params['candidate_count'])
+    end
+    if params.has_key?('vote_minimum')
+      apply_vote_minimum(votes, params['vote_minimum'])
+    end
+    if params.has_key?('percent_minimum')
+      apply_vote_minimum(votes, votes_sum * params['percent_minimum'])
+    end
+    if params.has_key?('percent_retention')
+      apply_retention(votes, votes_sum * params['percent_retention'])
+    end
+    
+    begin
+      ranked_candidates = votes.sort do |a, b|
+        b[1][0] <=> a[1][0]
+      end.collect {|i| i[0]}
+      @winners = ranked_candidates.find_all do |i|
+        votes[i][0] >= @majority
+      end
+    end while not self.winner? and next_round(votes, ranked_candidates)
+    @ranked_candidates.unshift(*ranked_candidates)
+  end
+
+protected
+  def apply_candidate_count(votes, candidate_count)
+    if votes.size > candidate_count
+      losers = votes.sort do |a, b|
+        b[1][0] <=> a[1][0]
+      end.collect {|i| i[0]}.last(votes.size - candidate_count)
+      @ranked_candidates.unshift(losers) unless losers.empty?
+      losers.each { |loser| remove_candidate(votes, loser) }
+    end
+  end
+
+  def apply_vote_minimum(votes, vote_minimum)
+    losers = votes.find_all do |i|
+      i[1][0] < vote_minimum
+    end.collect {|i| i[0]}
+    if losers.length == votes.size
+      votes.clear
+    else
+      @ranked_candidates.unshift(losers) unless losers.empty?
+      losers.each { |loser| remove_candidate(votes, loser) }
+    end
+  end
+
+  def apply_retention(votes, retention)
+    losers = votes.sort do |a, b|
+      b[1][0] <=> a[1][0]
+    end.collect {|i| i[0]}
+    partial_sum = 0
+    while partial_sum < retention
+      partial_sum += votes[losers.shift][0]
+    end
+    @ranked_candidates.unshift(losers) unless losers.empty?
+    losers.each { |loser| remove_candidate(votes, loser) }
+  end
+  
+  def next_round(votes, ranked_candidates)
+    loser = ranked_candidates[-1]
+    if votes.empty? or votes[loser][0] == votes[ranked_candidates[-2]][0]
+      false
+    else
+      @ranked_candidates.unshift(loser)
+      remove_candidate(votes, loser) 
+      true
+    end
+  end
+
+  def remove_candidate(votes, loser)
+    votes.each_pair do |candidate, morevotes|
+      hash = morevotes[1]
+      hash.each_pair do |vote, count|
+        hash.delete(vote)
+        vote.delete(loser)
+        hash[vote] = count
+      end
+    end
+    votes[loser][1].each_pair do |vote, count|
+      candidate = vote.shift
+      votes[candidate][0] += count
+      if votes[candidate][1].has_key?(vote)
+        votes[candidate][1][vote] += count
+      else
+        votes[candidate][1][vote] = count
+      end
+    end
+    votes.delete(loser)
+  end
+end
+
+class InstantRunoffLogicResult < InstantRunoffResult
+  def next_round(votes, ranked_candidates)
+    losers = ranked_candidates.find_all do |i|
+      votes[i][0] == votes[ranked_candidates[-1]][0]
+    end
+    if losers.inject(0) {|n, loser| n + votes[loser][0]} >= @majority
+      false
+    else
+      @ranked_candidates.unshift(losers)
+      losers.each do |loser|
+        remove_candidate(votes, loser)
+      end
+      true
+    end
+  end
+end
+
+class InstantRunoffFirstRoundResult < InstantRunoffResult
+  def next_round(votes, ranked_candidates)
+    losers = ranked_candidates.find_all do |i|
+      votes[i][0] == votes[ranked_candidates[-1]][0]
+    end
+    loser = losers.sort do |a, b|
+      @election.votes[a][0] <=> @election.votes[b][0]
+    end.last
+    @ranked_candidates.unshift(loser)
+    remove_candidate(votes, loser)
+  end
+end
+
+class InstantRunoffAllResult < InstantRunoffResult
+  def next_round(votes, ranked_candidates)
+    losers = ranked_candidates.find_all do |i|
+      votes[i][0] == votes[ranked_candidates[-1]][0]
+    end
+    if losers.length == ranked_candidates.length
+      false
+    else
+      @ranked_candidates.unshift(losers)
+      losers.each do |loser|
+        remove_candidate(votes, loser)
+      end
+      true
+    end
+  end
+end
+
+class InstantRunoffRandomResult < InstantRunoffResult
+  def next_round(votes, ranked_candidates)
+    losers = ranked_candidates.find_all do |i|
+      votes[i][0] == votes[ranked_candidates[-1]][0]
+    end
+    loser = losers[rand(losers.length)]
+    @ranked_candidates.unshift(loser)
+    remove_candidate(votes, loser)
+  end
+end
diff --git a/lib/rubyvote/runoff.rb b/lib/rubyvote/runoff.rb
deleted file mode 100644
index 8a69a4e..0000000
--- a/lib/rubyvote/runoff.rb
+++ /dev/null
@@ -1,88 +0,0 @@
-class InstantRunoffVote < ElectionVote
-  def initialize(votes=nil)
-    @candidates = Array.new
-    votes.each do |vote|
-      @candidates = vote.uniq if vote.uniq.length > candidates.length
-    end
-    super(votes)
-    @candidates.each do |candidate|
-      @votes[candidate] = [0, Hash.new] unless @votes.has_key?(candidate)
-    end
-  end
-
-  def result
-    InstantRunoffResult.new(self)
-  end
-  
-  protected
-  def tally_vote(vote)
-    votecopy = vote.dup
-    candidate = votecopy.shift
-    votes[candidate] = [0, Hash.new] unless votes.has_key?(candidate)
-    votes[candidate][0] += 1
-    if votes[candidate][1].has_key?(votecopy)
-      votes[candidate][1][votecopy] += 1
-    else
-      votes[candidate][1][votecopy] = 1
-    end
-  end
-
-  def verify_vote(vote=nil)
-    vote.instance_of?( Array ) and
-      vote == vote.uniq
-  end
-end
-
-class InstantRunoffResult < ElectionResult
-  attr_reader :ranked_candidates
-
-  def initialize(voteobj=nil)
-    unless voteobj and voteobj.kind_of?( InstantRunoffVote )
-      raise ArgumentError, "You must pass an InstantRunoffVote array.", caller
-    end
-    super(voteobj)
-
-    votes = @election.votes.clone
-    candidates = @election.candidates
-    majority = votes.inject(0) {|n, value| n + value[1][0]}/2 + 1
-    @ranked_candidates = Array.new()
-    ranked_candidates = Array.new()
-
-    loop do
-      ranked_candidates = votes.sort do |a, b|
-        b[1][0] <=> a[1][0]
-      end.collect {|i| i[0]}
-      @winners = ranked_candidates.find_all do |i|
-        votes[i][0] >= majority
-      end
-      
-      loser = ranked_candidates[-1]
-      break if self.winner? or votes[loser][0] == votes[ranked_candidates[-2]][0]
-
-      @ranked_candidates.unshift(loser)
-      runoff(votes, loser) 
-    end
-    @ranked_candidates.unshift(*ranked_candidates)
-  end
-
-  def runoff(votes, loser)
-    votes.each_pair do |candidate, morevotes|
-      hash = morevotes[1]
-      hash.each_pair do |vote, count|
-        hash.delete(vote)
-        vote.delete(loser)
-        hash[vote] = count
-      end
-    end
-    votes[loser][1].each_pair do |vote, count|
-      candidate = vote.shift
-      votes[candidate][0] += count
-      if votes[candidate][1].has_key?(vote)
-        votes[candidate][1][vote] += count
-      else
-        votes[candidate][1][vote] = count
-      end
-    end
-    votes.delete(loser)
-  end
-end