From 5b7cc16ac915f9c162406ac855b29e6819296e64 Mon Sep 17 00:00:00 2001
From: Ross Wightman <rwightman@gmail.com>
Date: Fri, 31 Jan 2020 11:43:34 -0800
Subject: [PATCH] Add warning about using sync-bn with zero initialized BN
 layers. Fixes #54

---
 train.py | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/train.py b/train.py
index e3eec357..bfb7568f 100755
--- a/train.py
+++ b/train.py
@@ -315,7 +315,9 @@ def main():
                 else:
                     model = torch.nn.SyncBatchNorm.convert_sync_batchnorm(model)
                 if args.local_rank == 0:
-                    logging.info('Converted model to use Synchronized BatchNorm.')
+                    logging.info(
+                        'Converted model to use Synchronized BatchNorm. WARNING: You may have issues if using '
+                        'zero initialized BN layers (enabled by default for ResNets) while sync-bn enabled.')
             except Exception as e:
                 logging.error('Failed to enable Synchronized BatchNorm. Install Apex or Torch >= 1.1')
         if has_apex: