How to Fix ModuleNotFoundError: No module named 'torch._six'

If you are using PyTorch and encounter the ModuleNotFoundError: No module named 'torch._six', it indicates an issue with an internal module that PyTorch used to depend on. This article will guide you through the steps to resolve this error effectively.

Understanding the Error

The torch._six module was a part of older versions of PyTorch and has since been deprecated. If you see this error, it’s likely because you are using code or a library that is not compatible with the current version of PyTorch.

from torch._six import inf
# ModuleNotFoundError: No module named 'torch._six'

This error typically occurs when you update PyTorch without updating other libraries that depend on it, such as torchvision or torchaudio.

Step 1: Update PyTorch and Related Libraries

To fix this error, you should ensure that all PyTorch-related libraries are updated to compatible versions. Use the following commands:

pip install torch torchvision torchaudio --upgrade

This will update torch, torchvision, and torchaudio to their latest versions, which should resolve the issue if it was caused by version mismatches.

Step 2: Downgrade PyTorch (If Needed)

If you are using older code that requires the torch._six module, consider downgrading PyTorch to a compatible version. For instance, you can install an older version of PyTorch using:

pip install torch==1.7.1

Make sure to verify which version of PyTorch your code or library requires before downgrading.

Step 3: Modify the Import Statement

If the library or code you are using references torch._six, you can modify the import statement as a workaround. For example, replace:

from torch._six import inf

with:

import math
inf = math.inf

This change replaces the deprecated import with a direct usage of Python's math library, which offers similar functionality.

Step 4: Use a Virtual Environment

To avoid conflicts between different library versions, use a virtual environment. Create and activate a virtual environment, then install the required versions of PyTorch:

python -m venv pytorch-env
source pytorch-env/bin/activate  # On Windows use: pytorch-env\Scripts\activate
pip install torch torchvision torchaudio

This isolates your Python environment and ensures compatibility between installed packages.

Troubleshooting

If the error persists, try these additional troubleshooting steps:

• Check for outdated libraries with pip list --outdated and update them.
• Clear pip cache and reinstall packages:

  pip cache purge
  

• Restart your IDE or development environment after making changes.

Additional Resources

If you encounter similar errors with other modules, refer to this guide for general solutions: How To Solve ModuleNotFoundError: No module named in Python.

Conclusion

The ModuleNotFoundError: No module named 'torch._six' error can be resolved by updating or downgrading PyTorch, modifying import statements, or using a virtual environment. Follow the steps above to get your PyTorch projects running without issues. Happy coding!