RuntimeError: Trying to backward through the graph a second time, but the buffers have already been

错误:

RuntimeError: Trying to backward through the graph a second time, but the buffers have already been freed. Specify retain_graph=True when calling backward the first time.
详细信息:

Traceback (most recent call last):
  File "main.py", line 21, in <module>
    startTrain.run(trainBatch)
  File "/root/train.py", line 49, in run
    loss.backward()
  File "/usr/local/lib/python3.7/site-packages/torch/tensor.py", line 102, in backward
    torch.autograd.backward(self, gradient, retain_graph, create_graph)
  File "/usr/local/lib/python3.7/site-packages/torch/autograd/__init__.py", line 90, in backward
    allow_unreachable=True)  # allow_unreachable flag
RuntimeError: Trying to backward through the graph a second time, but the buffers have already been freed. Specify retain_graph=True when calling backward the first time.

原因:

程序在试图执行backward的时候,发现计算图的缓冲区已经被释放

解决办法:

backward()函数中添加参数retain_graph=True
即:

loss.backward()

改为:

loss.backward(retain_graph=True)

你可能感兴趣的:(Python,深度学习,Pytorch)