diff --git a/egs/librispeech/ASR/transducer_stateless/diagnostics.py b/egs/librispeech/ASR/transducer_stateless/diagnostics.py
index 2dff91805..1a2324775 100644
--- a/egs/librispeech/ASR/transducer_stateless/diagnostics.py
+++ b/egs/librispeech/ASR/transducer_stateless/diagnostics.py
@@ -56,7 +56,8 @@ def get_sum_abs_stats(x: Tensor, dim: int,
         x = (x > 0).to(dtype=torch.float)
     orig_numel = x.numel()
     sum_dims = [ d for d in range(x.ndim) if d != dim ]
-    x = torch.sum(x, dim=sum_dims)
+    if len(sum_dims) != 0:
+        x = torch.sum(x, dim=sum_dims)
     count = orig_numel // x.numel()
     x = x.flatten()
     return x, count