big speed up

[rubyvote] / lib / rubyvote / condorcet.rb

diff --git a/lib/rubyvote/condorcet.rb b/lib/rubyvote/condorcet.rb
index f4ed7b74be0e7a9ec79d1ffe20f61fcfcab97ed2..e674115a89253359b62f18524280ed2c8f26c744 100644 (file)
--- a/lib/rubyvote/condorcet.rb
+++ b/lib/rubyvote/condorcet.rb
@@ -33,6 +33,22 @@
 
 class CondorcetVote < ElectionVote
 
+  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
+
   def tally_vote(vote=nil)
 
     vote.each_with_index do |winner, index|
@@ -43,14 +59,13 @@ class CondorcetVote < ElectionVote
       if vote.length - 1 == index
         losers = []
       else
-        losers = vote.last( vote.flatten.length - index )
+        losers = vote.flatten.last( vote.flatten.length - index - 1)
       end
 
       losers.each do |place|
         place = [place] unless place.class == Array
         place.each do |loser|
           
-          next if winner == loser
 
           @votes[winner] = Hash.new unless @votes.has_key?(winner)
           @votes[loser] = Hash.new unless @votes.has_key?(loser)
@@ -63,37 +78,50 @@ class CondorcetVote < ElectionVote
 
           # 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
+  end
 
-      @candidates << winner unless @candidates.include?( winner ) || 
-        winner.class == Array
+  def results
+    if @results.size < 2 && (not @candidates.empty?)
+      tabulate
     end
+    @results
   end
 
   def result
-    top_result = resultFactory( self )
-    until @candidates.empty?
-      aResult = resultFactory( self )
-      top_result.full_results << aResult
-      filter_out(aResult)
-    end
-    top_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 resultFactory(init)
-    PureCondorcetResult.new(init)
+  def result
+    PureCondorcetResult.new(self)
   end
 end
 
@@ -101,6 +129,7 @@ class CloneproofSSDVote < CondorcetVote
   def resultFactory(init)
     CloneproofSSDResult.new(init)
   end
+
 end
 
 
@@ -120,11 +149,13 @@ class CondorcetResult < ElectionResult
   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
@@ -175,6 +206,7 @@ class CloneproofSSDResult < CondorcetResult
   end
 
   protected
+
   def cpssd
     votes = @election.votes
     candidates = *@election.candidates
@@ -195,15 +227,22 @@ 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