（fast-reid）多GPU训练出现RuntimeError: Address already in use解决

https://github.com/JDAI-CV/fast-reid

0.环境 

ubuntu16.04
cuda9.0
python3.6
torch==1.1.0
torchvision==0.3.0
Cython
yacs
tensorboard
future
termcolor
sklearn
tqdm
opencv-python==4.1.0.25
matplotlib
scikit-image
faiss-gpu==1.6.3
tabulate
gdown

1.多次使用多GPU出现错误

RuntimeError: Address already in use

2.解决

usage: train_net.py [-h] [--config-file FILE] [--resume] [--eval-only][--num-gpus NUM_GPUS] [--num-machines NUM_MACHINES][--machine-rank