From 1825336841840b697782292801b3aa8adbad23df Mon Sep 17 00:00:00 2001
From: Daniel Povey <dpovey@gmail.com>
Date: Tue, 11 Oct 2022 11:04:40 +0800
Subject: [PATCH] Fix issue with diagnostics if stats is None

---
 icefall/diagnostics.py | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/icefall/diagnostics.py b/icefall/diagnostics.py
index 9d2ea46c9..c26e37de4 100644
--- a/icefall/diagnostics.py
+++ b/icefall/diagnostics.py
@@ -278,6 +278,8 @@ class TensorDiagnostic(object):
         """
         combined_name = _summarize_two_names(self.name, other.name)
         # e.g. combined_name == 'foo.{param_value,param_grad}' or just 'foo.param_value' if self.name == other.name.
+        if self.stats is None:
+            return
         for dim, this_dim_stats in enumerate(self.stats):
             try:
                 other_dim_stats = other.stats[dim]