PyTorch——解決報錯“RuntimeError: running_mean should contain *** elements not ***”

1 問題描述

在使用PyTorch編程的時候，經常遇到一種報錯就是：“RuntimeError: running_mean should contain *** elements not ***”；

這次我具體的報錯信息是：

  File "/home/songyuc/software/python/anaconda/anaconda3/envs/conda-general/lib/python3.7/site-packages/torch/nn/modules/module.py", line 541, in __call__
    result = self.forward(*input, **kwargs)
  File "/home/songyuc/software/python/anaconda/anaconda3/envs/conda-general/lib/python3.7/site-packages/torch/nn/modules/container.py", line 92, in forward
    input = module(input)
  File "/home/songyuc/software/python/anaconda/anaconda3/envs/conda-general/lib/python3.7/site-packages/torch/nn/modules/module.py", line 541, in __call__
    result = self.forward(*input, **kwargs)
  File "/home/songyuc/software/python/anaconda/anaconda3/envs/conda-general/lib/python3.7/site-packages/torch/nn/modules/batchnorm.py", line 81, in forward
    exponential_average_factor, self.eps)
  File "/home/songyuc/software/python/anaconda/anaconda3/envs/conda-general/lib/python3.7/site-packages/torch/nn/functional.py", line 1670, in batch_norm
    training, momentum, eps, torch.backends.cudnn.enabled
RuntimeError: running_mean should contain 192 elements not 768

從最後一行的報錯信息，可以看到：進行求均值元素的總數應該是192而不是768；

2 解決方案

我們可以繼續看看上一條提示信息：“File "/home/songyuc/software/python/anaconda/anaconda3/envs/conda-general/lib/python3.7/site-packages/torch/nn/functional.py", line 1670, in batch_norm”

有一個值得注意的信息是batch_norm，而我們的模型中也剛好使用了BN的操作，所以應該是BN的設置出現了問題，

我們回到代碼定位的部分進行查看，需要查看的是BN初始化設置的代碼，然後看到了下面的代碼：

modules = [nn.Sequential(
    nn.Conv2d(in_channels, OUT_CHANNELS, 1, groups=1, bias=False),
    nn.BatchNorm2d(in_channels),
    nn.ReLU()),

我們可以看到，果然，BatchNorm2d的輸入通道數與前一層Conv2d的輸出通道數不一致，而這裏的OUT_CHANNELS=192，in_channels=192，所以造成了這種維度的不一致，所以纔會報錯；

所以，我們需要根據自己模型的設計，將BN層與Conv層的輸出維度保持一致。