class_docstr: The standard BN layer computes stats across all examples in a GPU. In some
  cases it is desirable to compute stats across only a subset of examples
  (e.g., in multigrid training https://arxiv.org/abs/1912.00998).
  SubBatchNorm3d 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.
class_docstr_tok: ["The","standard","BN","layer","computes","stats","across","all","examples","in","a","GPU",".","In","some","cases","it","is","desirable","to","compute","stats","across","only","a","subset","of","examples","(","e.g.",",","in","multigrid","training","https",":","\/\/arxiv.org\/abs\/1912.00998",")",".","SubBatchNorm3d","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","."]
docstr: Synchronize running_mean, and running_var. Call this before eval.
docstr_tok: ["Synchronize","running_mean",",","and","running_var",".","Call","this","before","eval","."]
code: def aggregate_stats(self):
      """
      Synchronize running_mean, and running_var. Call this before eval.
      """
      if self.split_bn.track_running_stats:
          (
              self.bn.running_mean.data,
              self.bn.running_var.data,
          ) = self._get_aggregated_mean_std(
              self.split_bn.running_mean,
              self.split_bn.running_var,
              self.num_splits,
          )
  
file_path: SlowFast/slowfast/models/batchnorm_helper.py
imports: from functools import partial
  import torch
  import torch.nn
  from pytorchvideo.layers.batch_norm import NaiveSyncBatchNorm1d, NaiveSyncBatchNorm3d
label_desc: Use image node_id 3 for calling the SubBatchNorm3d obj's underlying member method code with example usage: obj.aggregate_stats() without return types