pytorch-lightning/pl_examples/multi_node_examples/README.md

# Multi-node example   

This demo launches a job using 2 GPUs on 2 different nodes (4 GPUs total).
To run this demo do the following:

1. Log into the jumphost node of your SLURM-managed cluster.  
2. Create a conda environment with Lightning and a GPU PyTorch version.   
3. Choose a script to submit    

#### DDP  
Submit this job to run with DistributedDataParallel (2 nodes, 2 gpus each)
```bash
sbatch ddp_job_submit.sh YourEnv
```

#### DDP2  
Submit this job to run with a different implementation of DistributedDataParallel.
In this version, each node acts like DataParallel but syncs across nodes like DDP.
```bash
sbatch ddp2_job_submit.sh YourEnv
```