用于梯度计算的变量被in-place操作

ERROR: test_autograd_backward (__main__.TestMode)
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Traceback (most recent call last):
  File "/root/miniconda3/envs/pt2.1/lib/python3.8/site-packages/torch/testing/_internal/common_utils.py", line 2388, in wrapper
    method(*args, **kwargs)
  File "npu/test_fault_mode.py", line 159, in test_autograd_backward
    torch.autograd.grad(d2.sum(), a)
  File "/root/miniconda3/envs/pt2.1/lib/python3.8/site-packages/torch/autograd/__init__.py", line 394, in grad
    result = Variable._execution_engine.run_backward(  # Calls into the C++ engine to run the backward pass
RuntimeError: one of the variables needed for gradient computation has been modified by an inplace operation: [torch.FloatTensor [5]], which is output 0 of AddBackward0, is at version 1; expected version 0 instead. Hint: enable anomaly detection to find the operation that failed to compute its gradient, with torch.autograd.set_detect_anomaly(True).