ERROR：
File "/home/wsx/.local/lib/python3.6/site-packages/mmdet/apis/inference.py", line 6, in <module> from mmcv.ops import RoIPool File "/home/wsx/anaconda3/envs/pvt/lib/python3.6/site-packages/mmcv/ops/__init__.py", line 2, in <module> from .assign_score_withk import assign_score_withk File "/home/wsx/anaconda3/envs/pvt/lib/python3.6/site-packages/mmcv/ops/assign_score_withk.py", line 6, in <module> '_ext', ['assign_score_withk_forward', 'assign_score_withk_backward']) File "/home/wsx/anaconda3/envs/pvt/lib/python3.6/site-packages/mmcv/utils/ext_loader.py", line 13, in load_ext ext = importlib.import_module('mmcv.' + name) File "/home/wsx/anaconda3/envs/pvt/lib/python3.6/importlib/__init__.py", line 126, in import_module return _bootstrap._gcd_import(name[level:], package, level) ImportError: /home/wsx/anaconda3/envs/pvt/lib/python3.6/site-packages/mmcv/_ext.cpython-36m-x86_64-linux-gnu.so: undefined symbol: _ZNK2at6Tensor6deviceEv
原因：
mmcv-full版本和pytorch不匹配
Solution：
先卸载之前的版本
pip uninstall mmcv-full
安装新的：
pip install mmcv-full -f https://download.openmmlab.com/mmcv/dist/cu101/torch1.8.1/index.html
tip：
确认cuda版本，上面是cuda=10.1, torch=1.8.1，根据自己需要安装相应版本
nvcc -v确认cuda版本
pip list | grep torch确认torch的版本
结果又报错：
AssertionError: MMCV==1.5.0 is used but incompatible. Please install mmcv>=1.3.2, <=1.4.0
解决：
pip install mmcv-full==1.3.15 -f https://download.openmmlab.com/mmcv/dist/cu101/torch1.8.1/index.html
O了
个人ubuntu 下pvt环境构建
conda install -c pytorch pytorch torchvision #torch==1.7.0 pip install mmcv-full==1.3.15 -f https://download.openmmlab.com/mmcv/dist/cu101/torch1.7.0/index.html
