From 59ac8bfc70a0062bc32b341e2bd1089f61a1011c Mon Sep 17 00:00:00 2001
From: emilyluj <49872352+emilyluj@users.noreply.github.com>
Date: Thu, 9 Feb 2023 18:32:03 +0800
Subject: [PATCH] fix mmi graph compiler bug. (#895)

---
 icefall/mmi_graph_compiler.py | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/icefall/mmi_graph_compiler.py b/icefall/mmi_graph_compiler.py
index 9f680f83d..600f09f2b 100644
--- a/icefall/mmi_graph_compiler.py
+++ b/icefall/mmi_graph_compiler.py
@@ -74,7 +74,9 @@ class MmiTrainingGraphCompiler(object):
         # CAUTION: The following line is crucial.
         # Arcs entering the back-off state have label equal to #0.
         # We have to change it to 0 here.
-        P.labels[P.labels >= first_token_disambig_id] = 0
+        labels = P.labels.clone()
+        labels[labels >= first_token_disambig_id] = 0
+        P.labels = labels
 
         P = k2.remove_epsilon(P)
         P = k2.arc_sort(P)