Contributing to Torchvision

We want to make contributing to this project as easy and transparent as possible.

TL;DR

We appreciate all contributions. If you are interested in contributing to Torchvision, there are many ways to help out. Your contributions may fall into the following categories:

It helps the project if you could
- Report issues you're facing
- Give a 👍 on issues that others reported and that are relevant to you
Answering queries on the issue tracker, investigating bugs are very valuable contributions to the project.
You would like to improve the documentation. This is no less important than improving the library itself! If you find a typo in the documentation, do not hesitate to submit a GitHub pull request.
If you would like to fix a bug
- please pick one from the list of open issues labelled as "help wanted"
- comment on the issue that you want to work on this issue
- send a PR with your fix, see below.
If you plan to contribute new features, utility functions or extensions, please first open an issue and discuss the feature with us.

Issues

We use GitHub issues to track public bugs. Please ensure your description is clear and has sufficient instructions to be able to reproduce the issue.

Development installation

Dependencies

Start by installing the nightly build of PyTorch following the official instructions. Note that the official instructions may ask you to install torchvision itself. If you are doing development on torchvision, you should not install prebuilt torchvision packages.

Optionally, install libpng, libjpeg-turbo and libwebp if you want to enable support for native encoding / decoding of PNG, JPEG and WebP formats in torchvision.io:

conda install libpng libjpeg-turbo libwebp -c pytorch

Note: you can use the TORCHVISION_INCLUDE and TORCHVISION_LIBRARY environment variables to tell the build system where to find those libraries if they are in specific locations. Take a look at setup.py for more details.

Clone and install torchvision

git clone https://github.com/pytorch/vision.git
cd vision
pip install -e . -v --no-build-isolation  # leave out the -e switch if you don't care about development.
# or, for OSX
# MACOSX_DEPLOYMENT_TARGET=10.9 CC=clang CXX=clang++ pip install -e . -v --no-build-isolation
# for C++ debugging, use DEBUG=1
# DEBUG=1 pip install -e . -v --no-build-isolation

By default, GPU support is built if CUDA is found and torch.cuda.is_available() is true. It's possible to force building GPU support by setting FORCE_CUDA=1 environment variable, which is useful when building a docker image.

We don't officially support building from source using pip, but if you do, you'll need to use the --no-build-isolation flag.

Other development dependencies (some of these are needed to run tests):

pip install expecttest flake8 typing mypy pytest pytest-mock scipy requests

Development Process

If you plan to modify the code or documentation, please follow the steps below:

Fork the repository and create your branch from main.
If you have modified the code (new feature or bug-fix), please add unit tests.
If you have changed APIs, update the documentation. Make sure the documentation builds.
Ensure the test suite passes.
Make sure your code passes the formatting checks (see below).

For more details about pull requests, please read GitHub's guides.

If you would like to contribute a new model, please see here.

If you would like to contribute a new dataset, please see here.

Code formatting and typing

Formatting

The torchvision code is formatted by black, and checked against pep8 compliance with flake8. Instead of relying directly on black however, we rely on ufmt, for compatibility reasons with Facebook internal infrastructure.

To format your code, install ufmt with pip install ufmt==1.3.3 black==22.3.0 usort==1.0.2 and use e.g.:

ufmt format torchvision

For the vast majority of cases, this is all you should need to run. For the formatting to be a bit faster, you can also choose to only apply ufmt to the files that were edited in your PR with e.g.:

ufmt format `git diff main --name-only`

Similarly, you can check for flake8 errors with flake8 torchvision, although they should be fairly rare considering that most of the errors are automatically taken care of by ufmt already.

Pre-commit hooks

For convenience and purely optionally, you can rely on pre-commit hooks which will run both ufmt and flake8 prior to every commit.

First install the pre-commit package with pip install pre-commit, and then run pre-commit install at the root of the repo for the hooks to be set up - that's it.

Feel free to read the pre-commit docs to learn more and improve your workflow. You'll see for example that pre-commit run --all-files will run both ufmt and flake8 without the need for you to commit anything, and that the --no-verify flag can be added to git commit to temporarily deactivate the hooks.

Type annotations

The codebase has type annotations, please make sure to add type hints if required. We use mypy tool for type checking:

mypy --config-file mypy.ini

Unit tests

Before running tests make sure to install test dependencies.

If you have modified the code by adding a new feature or a bug-fix, please add unit tests for that. To run a specific test:

pytest test/<test-module.py> -vvv -k <test_myfunc>
# e.g. pytest test/test_transforms.py -vvv -k test_center_crop

If you would like to run all tests:

pytest test -vvv

Tests that require internet access should be in test/test_internet.py.

Documentation

Torchvision uses Google style for formatting docstrings. Length of line inside docstrings block must be limited to 120 characters.

Please, follow the instructions to build and deploy the documentation locally.

Install requirements

cd docs
pip install -r requirements.txt

Build

cd docs
make html-noplot

Then open docs/build/html/index.html in your favorite browser.

The docs are also automatically built when you submit a PR. The job that builds the docs is named build_docs. You can access the rendered docs by clicking on that job and then going to the "Artifacts" tab.

You can clean the built docs and re-start the build from scratch by doing make clean.

Building the example gallery - or not

In most cases, running make html-noplot is enough to build the docs for your specific use-case. The noplot part tells sphinx not to build the examples in the gallery, which saves a lot of building time.

If you need to build all the examples in the gallery, then you can use make html.

You can also choose to only build a subset of the examples by using the EXAMPLES_PATTERN env variable, which accepts a regular expression. For example EXAMPLES_PATTERN="transforms" make html will only build the examples with "transforms" in their name.

New architecture or improved model weights

Please refer to the guidelines in Contributing to Torchvision - Models.

New dataset

Please, do not send any PR with a new dataset without discussing it in an issue as, most likely, it will not be accepted.

Pull Request

If all previous checks (flake8, mypy, unit tests) are passing, please send a PR. Submitted PR will pass other tests on different operating systems, python versions and hardware.

For more details about pull requests workflow, please read GitHub's guides.

License

By contributing to Torchvision, you agree that your contributions will be licensed under the LICENSE file in the root directory of this source tree.

Contributors are also required to sign our Contributor License Agreement.

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