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Many thanks for wanting to contribute to torch! We welcome all kinds of contributions, from correcting typos via bug fixes to feature additions.

Fixing typos

To fix typos, spelling mistakes, or grammatical errors, you need to make changes in the source .R file in question, not in the generated .Rd file. Thereafter, run tools/document.R to regenerate the documentation. (See Workflow below for why.)

Filing bugs

If you find a bug in torch, please open an issue here. Please provide detailed information on how to reproduce the bug. It would be great to also provide a reprex.

Feature requests

Feel free to open issues here, and add the feature-request tag. Also try searching if there’s already an open issue for your feature-request – in this case it’s better to comment or upvote it instead of opening a new one.


We welcome contributed examples. Feel free to open a PR with new examples. The examples should be placed in the vignettes/examples folder.

The examples should consist of an .R file and an .Rmd with the same name that just renders the code.

See mnist-mlp.R and mnist-mlp.Rmd for an example.

It’s important that one can run the example without manually downloading any dataset/file. You should also add an entry to the _pkgdown.yaml file for your example.

Code contributions

We have many open issues in the github repo. If there’s one item that you want to work on, you can comment on it and ask for directions.

Code style

  • New R code should follow the tidyverse style guide. You can use the styler package to apply these styles, or simply run the tools/ script, which also formats the code and removes whitespace. Please don’t re-style code that has nothing to do with your PR.

  • New C/C++ code should follow the Google style guide. You can use clang-format to apply these styles, or simply run tools/, which also formats the code and removes whitespace. Please don’t re-style code that has nothing to do with your PR.

  • We use roxygen2, with Markdown syntax, to build all documentation for the package.

  • We use testthat for unit tests. Contributions with test cases included are easier to accept.


  • R installation
  • R Tools for compilation (only on Windows)
  • The devtools package
  • CMake to compile lantern binaries


We use devtools as the toolchain for development, but a few steps must be done before upfront.

The first time you clone the repository, run:


This will first download LibTorch and copy its binaries to the deps folder in the working directory, and then, compile the lantern binaries themselves.

This command must be run everytime you modify lantern code, i.e., code that lives in lantern/src.

You can then run


to load torch, and test interactively. Alternatively, run


to execute the test suite.

Finally, it’s important to update the documentation. Please always use the custom tools/document.R script instead of devtools::document(), as we need to patch roxygen2 to avoid running the examples on CRAN.

We’re looking forward to your contributions!