官方文档：Installation — detectron2 0.6 documentation
环境要求：
python>=3.6
PyTorch>=1.8
git clone https://github.com/facebookresearch/detectron2.git
python -m pip install -e detectron2
报错：
没有安装pytorch
报错：
ERROR: Command errored out with exit status 1: python setup.py egg_inf
解决：
pip install --upgrade setuptools && python -m pip install --upgrade pip
报错：
error: command ‘:/usr/local/cuda-10.2/bin/nvcc’ failed with exit status 1
No such file or directory: ‘:/usr/local/cuda-10.1:/usr/local/cuda-10.1/bin/nvcc‘:
SetuptoolsDeprecationWarning: setup.py install is deprecated. Use build and pip and other standards-based tools.
找不到nvcc，但是nvidia-smi和nvcc -V都正常
解决：gedit ~/.bashrc
将：export CUDA_HOME=$CUDA_HOME:/usr/local/cuda-10.2
改为：export CUDA_HOME=/usr/local/cuda-10.2
保存后退出，刷新环境变量
source ~/.bashrc
重新进入终端，重新进入虚拟环境。
