Install PyTorch Lightning in Python

PyTorch Lightning simplifies deep learning research. It makes PyTorch code cleaner and more modular. This guide will help you install it easily.

Prerequisites

Before installing PyTorch Lightning, ensure you have Python 3.6 or later. You also need PyTorch installed. Check your Python version using python --version.

 
# Check Python version
import sys
print(sys.version)

3.8.5 (default, Jan 27 2021, 15:41:15)

Install PyTorch First

PyTorch Lightning depends on PyTorch. Install PyTorch using pip or conda. Choose the command that matches your setup.

 
# For pip users
pip install torch torchvision torchaudio

# For conda users
conda install pytorch torchvision torchaudio -c pytorch

If you face issues, check our guide on How To Solve ModuleNotFoundError: No module named in Python.

Install PyTorch Lightning

Once PyTorch is installed, install PyTorch Lightning. Use pip for a simple installation.

 
pip install pytorch-lightning

For the latest features, install the bleeding-edge version from GitHub.

 
pip install git+https://github.com/PyTorchLightning/pytorch-lightning.git@master

Verify Installation

After installation, verify it works. Import PyTorch Lightning in Python.

 
import pytorch_lightning as pl
print(pl.__version__)

1.5.0

Important: If you see an error, check your PyTorch version. PyTorch Lightning needs compatible PyTorch.

Upgrade PyTorch Lightning

To upgrade PyTorch Lightning, use pip with the --upgrade flag.

 
pip install --upgrade pytorch-lightning

Common Installation Issues

Sometimes, installation fails. Here are common fixes.

1. PyTorch not found: Ensure PyTorch is installed first.

2. Version conflicts: Use virtual environments to avoid conflicts.

3. Permission errors: Use --user flag or sudo if needed.

Using Virtual Environments

Virtual environments prevent conflicts. Create one using venv.

 
python -m venv lightning_env
source lightning_env/bin/activate  # On Windows use `lightning_env\Scripts\activate`

Now install PyTorch Lightning inside the environment.

Conclusion

Installing PyTorch Lightning is simple. First, install PyTorch. Then, install PyTorch Lightning using pip. Verify the installation by importing it. Use virtual environments to avoid issues.

For more help, refer to the ModuleNotFoundError guide.