#filter_out and PureCondorcet weren't getting along well for sparse elections
[rubyvote] / lib / rubyvote / condorcet.rb
index 5f103fb..3269261 100644 (file)
 
 class CondorcetVote < ElectionVote
 
+  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)
+  end
+
   def tally_vote(vote=nil)
 
     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 )
-
-      losers.each do |loser|
-        next if winner == loser
+      if vote.flatten.length < @candidates.length
+        implied_losers = @candidates.select { |c| not vote.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|
+          
 
-        if @votes[winner].has_key?(loser)
-          @votes[winner][loser] += 1
-        else
-          @votes[winner][loser] = 1
-        end
+          @votes[winner] = Hash.new unless @votes.has_key?(winner)
+          @votes[loser] = Hash.new unless @votes.has_key?(loser)
 
-        # make sure we have a comparable object
-        @votes[loser][winner] = 0 unless @votes[loser].has_key?( winner )
+          if @votes[winner].has_key?(loser)
+            @votes[winner][loser] += 1
+          else
+            @votes[winner][loser] = 1
+          end
 
-        @candidates << loser unless @candidates.include?( loser )
+          # make sure we have a comparable object
+          @votes[loser][winner] = 0 unless @votes[loser].has_key?( winner )
+        end
       end
-
-      @candidates << winner unless @candidates.include?( winner )
     end
   end
 
   def result
-    top_result = resultFactory( self )
-    until @candidates.empty?
-      aResult = resultFactory( self )
-      top_result.full_results << aResult
-      filter_out(aResult)
-    end
-    top_result
+    resultFactory( self )
   end
 
   protected
@@ -90,6 +102,17 @@ class CloneproofSSDVote < CondorcetVote
   def resultFactory(init)
     CloneproofSSDResult.new(init)
   end
+
+  def result
+    top_result = resultFactory( self )
+    until @candidates.empty?
+      aResult = resultFactory( self )
+      top_result.full_results << aResult
+      filter_out(aResult)
+    end
+    top_result
+  end
+
 end
 
 
@@ -114,6 +137,7 @@ class CondorcetResult < ElectionResult
     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
@@ -185,6 +209,7 @@ class CloneproofSSDResult < CondorcetResult
       # see the array with the standard defeats
       transitive_defeats = self.defeats(candidates, votes)
 
+      candidates = [candidates] unless candidates.class == Array
       candidates.each do |cand1|
         candidates.each do |cand2|
           candidates.each do |cand3|

Benjamin Mako Hill || Want to submit a patch?