In the script 1, it describes using python -m torch.distributed.launch........ to spawn the processes but I see that the Pytorch ImageNet example does not use it and is able to spawn the processes too, so what’s the point of it? I see that a lot of 3rd party open-source training repo also call  torch.distributed.launch in their bash script for training. I am not very clear on what it does, seems like it setting the environment variables?
Pytorch imagenet example without the usage of the launch file: examples/imagenet at master · pytorch/examples · GitHub
It will be very nice if there’s an example of using the launch file in the pytorch example to see what’s the difference.