[Docs] Add Subbn docs (#1503)

* master * master 0721 * add README * 1231 bump_version * 0207 slowfast steplr * 0207 * add subbn docs * add subbn docs
open-mmlab · Mar 11, 2022 · 4ce921b · 4ce921b
1 parent fa6eea8
commit 4ce921b
Showing 1 changed file with 4 additions and 1 deletion.
diff --git a/mmaction/models/common/sub_batchnorm3d.py b/mmaction/models/common/sub_batchnorm3d.py
@@ -8,7 +8,10 @@
 
 @NORM_LAYERS.register_module()
 class SubBatchNorm3D(nn.Module):
-    """Sub BatchNorm3d.
+    """Sub BatchNorm3d splits the batch dimension into N splits, and run BN on
+    each of them separately (so that the stats are computed on each subset of
+    examples (1/N of batch) independently). During evaluation, it aggregates
+    the stats from all splits into one BN.
 
     Args:
         num_features (int): Dimensions of BatchNorm.