jetson安装pytorch1.7后import报错ImportError: cannot import name ‘Final‘

硬件配置

Jetson Nano 4G -Jetpack 4.5.1 [L4T 32.5.1]

参考

nv官方安装指南：https://forums.developer.nvidia.com/t/pytorch-for-jetson-version-1-9-0-now-available/72048
网上搜到的pytorch1.7安装教程：https://blog.openpilot.cc/archives/2271

报错信息

>>> import torch
Traceback (most recent call last):
  File "", line 1, in <module>
  File "/home/ubuntu/.local/lib/python3.6/site-packages/torch/__init__.py", line 524, in <module>
    from .functional import *
  File "/home/ubuntu/.local/lib/python3.6/site-packages/torch/functional.py", line 6, in <module>
    import torch.nn.functional as F
  File "/home/ubuntu/.local/lib/python3.6/site-packages/torch/nn/__init__.py", line 1, in <module>
    from .modules import *
  File "/home/ubuntu/.local/lib/python3.6/site-packages/torch/nn/modules/__init__.py", line 2, in <module>
    from .linear import Identity, Linear, Bilinear
  File "/home/ubuntu/.local/lib/python3.6/site-packages/torch/nn/modules/linear.py", line 6, in <module>
    from .. import functional as F
  File "/home/ubuntu/.local/lib/python3.6/site-packages/torch/nn/functional.py", line 12, in <module>
    from .._jit_internal import boolean_dispatch, List, Optional, _overload, Tuple
  File "/home/ubuntu/.local/lib/python3.6/site-packages/torch/_jit_internal.py", line 27, in <module>
    from typing_extensions import Final
ImportError: cannot import name 'Final'

解决方法

       笔者的安装步骤和两个参考教程都是基本一样的，估计大方向没有问题。看起来问题在于最后一个报错from typing_extensions import Final ImportError: cannot import name 'Final'，可能是typing_extensions版本问题(新版本删除了Final之类的)。在网上找到torch1.7对应的typing_extensions版本是3.7.4.3，卸载原来版本的typing_extensions，运行pip3 install typing_extensions==3.7.4.3安装对应版本typing_extensions。这时候就可以成功import torch了。