PyTorch Setup

Prerequisites: (Make sure to read the following before using this example!)

The full source code for this example is available on the mila-docs GitHub repository.

#SBATCH --gres=gpu:1
#SBATCH --cpus-per-task=1
#SBATCH --mem=16G
#SBATCH --time=00:15:00

set -e  # exit on error.
echo "Date:     $(date)"
echo "Hostname: $(hostname)"

# Ensure only anaconda/3 module loaded.
module --quiet purge
# This example uses Conda to manage package dependencies.
# See for more information.
module load anaconda/3

# Creating the environment for the first time:
# conda create -y -n pytorch python=3.9 pytorch torchvision torchaudio \
#     pytorch-cuda=11.6 -c pytorch -c nvidia
# Other conda packages:
# conda install -y -n pytorch -c conda-forge rich

# Activate the environment:
conda activate pytorch

# Fixes issues with MIG-ed GPUs with versions of PyTorch < 2.0


import torch
import torch.backends.cuda

def main():
    cuda_built = torch.backends.cuda.is_built()
    cuda_avail = torch.cuda.is_available()
    device_count = torch.cuda.device_count()

    print(f"PyTorch built with CUDA:         {cuda_built}")
    print(f"PyTorch detects CUDA available:  {cuda_avail}")
    print(f"PyTorch-detected #GPUs:          {device_count}")
    if device_count == 0:
        print("    No GPU detected, not printing devices' names.")
        for i in range(device_count):
            print(f"    GPU {i}:      {torch.cuda.get_device_name(i)}")

if __name__ == "__main__":

Running this example

This assumes that you already created a conda environment named “pytorch”. To create this environment, we first request resources for an interactive job. Note that we are requesting a GPU for this job, even though we’re only going to install packages. This is because we want PyTorch to be installed with GPU support, and to have all the required libraries.

$ salloc --gres=gpu:1 --cpus-per-task=4 --mem=16G --time=00:30:00
salloc: --------------------------------------------------------------------------------------------------
salloc: # Using default long partition
salloc: --------------------------------------------------------------------------------------------------
salloc: Pending job allocation 2959785
salloc: job 2959785 queued and waiting for resources
salloc: job 2959785 has been allocated resources
salloc: Granted job allocation 2959785
salloc: Waiting for resource configuration
salloc: Nodes cn-g022 are ready for job
$ # Load anaconda
$ module load anaconda/3
$ # Create the environment (see the example):
$ conda create -n pytorch python=3.9 pytorch torchvision torchaudio pytorch-cuda=11.7 -c pytorch -c nvidia
$ # Press 'y' to accept if everything looks good.
$ # Activate the environment:
$ conda activate pytorch

Exit the interactive job once the environment has been created. Then, the example can be launched to confirm that everything works:

$ sbatch