From ef8289c7f153736041594819b1fa112a2a37d862 Mon Sep 17 00:00:00 2001
From: Alpha Chen <alpha@kejadlen.dev>
Date: Fri, 23 Jun 2023 19:16:14 -0700
Subject: [PATCH] allow for rating single-rating teams

---
 lib/rank_king.rb            | 4 ++--
 lib/rank_king/open_skill.rb | 4 +++-
 2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/lib/rank_king.rb b/lib/rank_king.rb
index 858bfa2..de7e0e4 100644
--- a/lib/rank_king.rb
+++ b/lib/rank_king.rb
@@ -13,7 +13,7 @@ module RankKing
       ratings = combo.map {|item| Rating.first(axis:, item:) || OS.rating }
       Math.sqrt(
         [ratings, ratings.reverse]
-          .map {|game| [game, OS.rate(game.map {[_1]}).flatten] }
+          .map {|game| [game, OS.rate(game).flatten] }
           .sum {|pre,post| pre.zip(post).sum { (_1.sigma - _2.sigma)**2 }}
       )
     }.last
@@ -23,7 +23,7 @@ module RankKing
     fail unless [winner, loser].all? { _1.pool == axis.pool }
 
     game = [winner, loser].map { Rating.first(axis:, item: _1) || OS.rating }
-    result = OS.rate(game.map { [_1] }).flatten
+    result = OS.rate(game).flatten
 
     DB.transaction do
       Ranking.create(axis:, winner:, loser:)
diff --git a/lib/rank_king/open_skill.rb b/lib/rank_king/open_skill.rb
index 5598e5b..5234be3 100644
--- a/lib/rank_king/open_skill.rb
+++ b/lib/rank_king/open_skill.rb
@@ -18,8 +18,10 @@ module RankKing
     end
 
     # TODO take an implicit array
-    # TODO array-ify elements
     def rate(teams)
+      # allow for passing in single-rating teams
+      teams = teams.map { Array(_1) }
+
       # tau keeps sigma from dropping too low so that ratings stay pliable
       # after many games
       tau_sq = @tau ** 2