From 7e40534e23e244de1f4ef83aa79313e71999d29c Mon Sep 17 00:00:00 2001
From: Lionel Panhaleux <lionel.panhaleux@gmail.com>
Date: Mon, 16 Sep 2024 09:28:45 +0200
Subject: [PATCH] Fix minor seating issue

---
 CHANGELOG.rst         | 2 +-
 krcg/seating.py       | 2 +-
 tests/test_seating.py | 6 ++++++
 3 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index 15585c7..49e8763 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -4,7 +4,7 @@ Changelog
 4.1 (unreleased)
 ----------------
 
-- Nothing changed yet.
+- Fix a niche case seating score error (players playing twice in rare situations)
 
 
 4.0 (2024-09-15)
diff --git a/krcg/seating.py b/krcg/seating.py
index f36222b..bfbf3b1 100644
--- a/krcg/seating.py
+++ b/krcg/seating.py
@@ -393,7 +393,7 @@ def fast_total(measure: Measure, rounds_count: int) -> float:
             # Transfers difference
             numpy.sum((transfers - numpy.mean(transfers)) ** 2) / transfers.size,
             # same position groups for an opponent twice
-            numpy.count_nonzero(opponents_twice[6:] > 1) // 2 if collisions else 0,
+            numpy.count_nonzero(opponents_twice[:, 6:] > 1) // 2 if collisions else 0,
         ]
         # builtins.sum is expensive
         return (
diff --git a/tests/test_seating.py b/tests/test_seating.py
index ec43a56..8a2d0f2 100644
--- a/tests/test_seating.py
+++ b/tests/test_seating.py
@@ -267,6 +267,12 @@ def test_score():
     ]
     assert score.rules == [0, 10, 0, 10, 0, 0, 3, 0.9092121131323905, 10]
     assert score.total == 10010003100.921211
+    # fast total is slightly lower because it does not sqrt the stdevs.
+    # it has no impact in the "ordering" of solutions though, so it's fine
+    pm = seating.player_mapping(rounds)
+    measure = sum(seating.measure(pm, r) for r in rounds)
+    fast_total = seating.Score.fast_total(measure, len(rounds))
+    assert fast_total == 10010003092.666666
 
 
 def test_optimise():