报错如下:

 warnings.warn(
WARNING:torch.distributed.run:
*****************************************
Setting OMP_NUM_THREADS environment variable for each process to be 1 in default, to avoid your system being overloaded, please further tune the variable for optimal performance in your application as needed. 
*****************************************
usage: train.py [-h] [--weights WEIGHTS] [--cfg CFG] [--data DATA] [--hyp HYP] [--epochs EPOCHS] [--batch-size BATCH_SIZE]
                [--img-size IMG_SIZE [IMG_SIZE ...]] [--rect] [--resume [RESUME]] [--nosave] [--notest] [--noautoanchor] [--evolve] [--bucket BUCKET]
                [--cache-images] [--image-weights] [--device DEVICE] [--multi-scale] [--single-cls] [--adam] [--sync-bn] [--local_rank LOCAL_RANK]
                [--workers WORKERS] [--project PROJECT] [--entity ENTITY] [--name NAME] [--exist-ok] [--quad] [--linear-lr]
                [--label-smoothing LABEL_SMOOTHING] [--upload_dataset] [--bbox_interval BBOX_INTERVAL] [--save_period SAVE_PERIOD]
                [--artifact_alias ARTIFACT_ALIAS] [--freeze FREEZE [FREEZE ...]] [--v5-metric]
usage: train.py [-h] [--weights WEIGHTS] [--cfg CFG] [--data DATA] [--hyp HYP] [--epochs EPOCHS] [--batch-size BATCH_SIZE]
                [--img-size IMG_SIZE [IMG_SIZE ...]] [--rect] [--resume [RESUME]] [--nosave] [--notest] [--noautoanchor] [--evolve] [--bucket BUCKET]
                [--cache-images] [--image-weights] [--device DEVICE] [--multi-scale] [--single-cls] [--adam] [--sync-bn] [--local_rank LOCAL_RANK]
                [--workers WORKERS] [--project PROJECT] [--entity ENTITY] [--name NAME] [--exist-ok] [--quad] [--linear-lr]
                [--label-smoothing LABEL_SMOOTHING] [--upload_dataset] [--bbox_interval BBOX_INTERVAL] [--save_period SAVE_PERIOD]
                [--artifact_alias ARTIFACT_ALIAS] [--freeze FREEZE [FREEZE ...]] [--v5-metric]
train.py: error: unrecognized arguments: --local-rank=2
train.py: error: unrecognized arguments: --local-rank=0
usage: train.py [-h] [--weights WEIGHTS] [--cfg CFG] [--data DATA] [--hyp HYP] [--epochs EPOCHS] [--batch-size BATCH_SIZE]
                [--img-size IMG_SIZE [IMG_SIZE ...]] [--rect] [--resume [RESUME]] [--nosave] [--notest] [--noautoanchor] [--evolve] [--bucket BUCKET]
                [--cache-images] [--image-weights] [--device DEVICE] [--multi-scale] [--single-cls] [--adam] [--sync-bn] [--local_rank LOCAL_RANK]
                [--workers WORKERS] [--project PROJECT] [--entity ENTITY] [--name NAME] [--exist-ok] [--quad] [--linear-lr]
                [--label-smoothing LABEL_SMOOTHING] [--upload_dataset] [--bbox_interval BBOX_INTERVAL] [--save_period SAVE_PERIOD]
                [--artifact_alias ARTIFACT_ALIAS] [--freeze FREEZE [FREEZE ...]] [--v5-metric]
train.py: error: unrecognized arguments: --local-rank=1
ERROR:torch.distributed.elastic.multiprocessing.api:failed (exitcode: 2) local_rank: 0 (pid: 27361) of binary: /home/guoqr/anaconda3/envs/yolov8/bin/python
Traceback (most recent call last):
  File "/home/guoqr/anaconda3/envs/yolov8/lib/python3.8/runpy.py", line 194, in _run_module_as_main
    return _run_code(code, main_globals, None,
  File "/home/guoqr/anaconda3/envs/yolov8/lib/python3.8/runpy.py", line 87, in _run_code
    exec(code, run_globals)
  File "/home/guoqr/anaconda3/envs/yolov8/lib/python3.8/site-packages/torch/distributed/launch.py", line 196, in <module>
    main()
  File "/home/guoqr/anaconda3/envs/yolov8/lib/python3.8/site-packages/torch/distributed/launch.py", line 192, in main
    launch(args)
  File "/home/guoqr/anaconda3/envs/yolov8/lib/python3.8/site-packages/torch/distributed/launch.py", line 177, in launch
    run(args)
  File "/home/guoqr/anaconda3/envs/yolov8/lib/python3.8/site-packages/torch/distributed/run.py", line 785, in run
    elastic_launch(
  File "/home/guoqr/anaconda3/envs/yolov8/lib/python3.8/site-packages/torch/distributed/launcher/api.py", line 134, in __call__
    return launch_agent(self._config, self._entrypoint, list(args))
  File "/home/guoqr/anaconda3/envs/yolov8/lib/python3.8/site-packages/torch/distributed/launcher/api.py", line 250, in launch_agent
    raise ChildFailedError(
torch.distributed.elastic.multiprocessing.errors.ChildFailedError: 
============================================================
train.py FAILED
------------------------------------------------------------
Failures:
[1]:
  time      : 2023-04-20_20:49:25
  host      : wsn-Server1F
  rank      : 1 (local_rank: 1)
  exitcode  : 2 (pid: 27362)
  error_file: <N/A>
  traceback : To enable traceback see: https://pytorch.org/docs/stable/elastic/errors.html
[2]:
  time      : 2023-04-20_20:49:25
  host      : wsn-Server1F
  rank      : 2 (local_rank: 2)
  exitcode  : 2 (pid: 27364)
  error_file: <N/A>
  traceback : To enable traceback see: https://pytorch.org/docs/stable/elastic/errors.html
------------------------------------------------------------
Root Cause (first observed failure):
[0]:
  time      : 2023-04-20_20:49:25
  host      : wsn-Server1F
  rank      : 0 (local_rank: 0)
  exitcode  : 2 (pid: 27361)
  error_file: <N/A>
  traceback : To enable traceback see: https://pytorch.org/docs/stable/elastic/errors.html
============================================================

由上图可以看出是–local_rank 与 --local-rank不一致导致的，追究原因，竟然是torch2.0版本launch.py里面写的全是–local-rank，而本yolov7源码用的是–local_rank

解决方法

第一种方法：把train.py里面的local_rank全改成local-rank
第二种方法：更换torch版本，我把torch版本换成1.13就好了。