From 38c2845c3c5b201967a3bd4433fb87c33851b764 Mon Sep 17 00:00:00 2001
From: "Thomas (Tom) C. Gorordo" <57684088+tgorordo@users.noreply.github.com>
Date: Fri, 12 Jun 2026 15:05:27 -0700
Subject: [PATCH] Update rcv.py to handle ties correctly

---
 src/smithy/rcv.py | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/smithy/rcv.py b/src/smithy/rcv.py
index 4f51fe2..120d095 100644
--- a/src/smithy/rcv.py
+++ b/src/smithy/rcv.py
@@ -59,6 +59,9 @@ def pmg_from_rcv_bigslow(ballots: pl.DataFrame) -> rwx.PyDiGraph:
             pmg.add_edge(nodes[a], nodes[b], a_wins - b_wins)
         elif b_wins > a_wins:
             pmg.add_edge(nodes[b], nodes[a], b_wins - a_wins)
+        else: # tie
+            pmg.add_edge(nodes[a], nodes[b], 0)
+            pmg.add_edge(nodes[b], nodes[a], 0)
 
     return pmg
 
@@ -105,6 +108,9 @@ def pmg_from_rcv_smallfast(ballots: pl.DataFrame) -> rwx.PyDiGraph:
                 pmg.add_edge(nodes[a], nodes[b], int(a_wins - b_wins))
             elif b_wins > a_wins:
                 pmg.add_edge(nodes[b], nodes[a], int(b_wins - a_wins))
+            else: # tie
+                pmg.add_edge(nodes[a], nodes[b], 0)
+                pmg.add_edge(nodes[b], nodes[a], 0)
 
     return pmg