Error：Given input size: (256x4x2). Calculated output size: (256x1x0). Output size is too small_runtimeerror: given input size: (128x5x5). calcula

Traceback (most recent call last):
  File "cls_set.py", line 62, in <module>
    main()
  File "cls_set.py", line 50, in main
    output = model(input_var)
  File "/usr/local/lib64/python3.6/site-packages/torch/nn/modules/module.py", line 532, in __call__
    result = self.forward(*input, **kwargs)
  File "/usr/local/lib64/python3.6/site-packages/torchvision/models/alexnet.py", line 45, in forward
    x = self.features(x)
  File "/usr/local/lib64/python3.6/site-packages/torch/nn/modules/module.py", line 532, in __call__
    result = self.forward(*input, **kwargs)
  File "/usr/local/lib64/python3.6/site-packages/torch/nn/modules/container.py", line 100, in forward
    input = module(input)
  File "/usr/local/lib64/python3.6/site-packages/torch/nn/modules/module.py", line 532, in __call__
    result = self.forward(*input, **kwargs)
  File "/usr/local/lib64/python3.6/site-packages/torch/nn/modules/pooling.py", line 141, in forward
    self.return_indices)
  File "/usr/local/lib64/python3.6/site-packages/torch/_jit_internal.py", line 181, in fn
    return if_false(*args, **kwargs)
  File "/usr/local/lib64/python3.6/site-packages/torch/nn/functional.py", line 488, in _max_pool2d
    input, kernel_size, stride, padding, dilation, ceil_mode)
RuntimeError: Given input size: (256x4x2). Calculated output size: (256x1x0). Output size is too small

原因：图片太小，没有拉伸，进入网络后池化不够大

解决：修改了pooling层（网络结构改错了）