From d28621e0b11f6e5f2971f0694726c5a926ab28ba Mon Sep 17 00:00:00 2001
From: Justin Sharps <jlsharps@alum.mit.edu>
Date: Thu, 16 Aug 2007 19:55:53 +0000
Subject: [PATCH] Created the list_defeats method in the CondorcetResult Class,
 so it hsould apply both to PureCondorcet and SSD votes. It helps in
 outputting a list of who beat whom, and by how much. It also stores ties.

git-svn-id: svn://rubyforge.org/var/svn/rubyvote/trunk@40 1440c7f4-e209-0410-9a04-881b5eb134a8
---
 lib/rubyvote/condorcet.rb | 26 ++++++++++++++++++++++++--
 1 file changed, 24 insertions(+), 2 deletions(-)

diff --git a/lib/rubyvote/condorcet.rb b/lib/rubyvote/condorcet.rb
index bf4e548..7153995 100644
--- a/lib/rubyvote/condorcet.rb
+++ b/lib/rubyvote/condorcet.rb
@@ -153,7 +153,29 @@ class CondorcetResult < ElectionResult
     super(voteobj)
     @matrix = voteobj.votes
   end
-
+  
+  def list_defeats
+    victors = Array.new
+    ties = Array.new
+    candidates = @matrix.keys.sort
+    
+    candidates.each do |candidate|
+      candidates.each do |challenger|
+        next if candidate == challenger
+        diff = @matrix[candidate][challenger] - @matrix[challenger][candidate]
+        if diff > 0 
+          victors << [candidate, challenger, diff]
+        elsif diff == 0 && ties.include?([challenger, candidate]) == false
+          ties << [candidate, challenger] 
+        end
+      end
+    end
+    
+    victories = victors.sort {|a,b| b[2] <=> a[2]}
+    
+    return victories, ties    
+  end
+        
   protected
   def defeats(candidates=nil, votes=nil)
     candidates = @election.candidates unless candidates
@@ -182,7 +204,7 @@ class PureCondorcetResult < CondorcetResult
   end
 
   protected
-
+  
   def condorcet
     votes = @election.votes
     candidates = @election.candidates
-- 
2.39.5