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lamW is an R package which calculates the real-valued branches of the Lambert-W function without the need to install the entire GSL. It uses compiled code and RcppParallel to achieve significant speed.


If you use the package, please cite it as:

Avraham Adler (2015). lamW: Lambert-W Function. R package version 2.2.0. doi: 10.5281/zenodo.5874874

A BibTeX entry for LaTeX users is:

    title = {lamW: Lambert-W Function},
    author = {Avraham Adler},
    year = {2015},
    url = {},
    doi = "10.5281/zenodo.5874874",
    note = {R package version 2.2.0.},


Please ensure that all contributions comply with both R and CRAN standards for packages.


This project attempts to follow Semantic Versioning


This project attempts to follow the changelog system at Keep a CHANGELOG


This project intends to have as few dependencies as possible. Please consider that when writing code.


Please conform to this coding style guide as best possible.


Please provide valid .Rd files and not roxygen-style documentation.


Please review the current test suite and supply similar tinytest-compatible unit tests for all added functionality.


If you would like to contribute to the project, it may be prudent to first contact the maintainer via email. A request or suggestion may be raised as an issue as well. To supply a pull request (PR), please:

  1. Fork the project and then clone into your own local repository
  2. Create a branch in your repository in which you will make your changes
  3. Ideally use -s to sign-off on commits under the Developer Certificate of Origin.
  4. If possible, sign commits using a GPG key.
  5. Push that branch and then create a pull request

At this point, the PR will be discussed and eventually accepted or rejected by the lead maintainer.






This package is a calculation engine and requires no secrets or private information. It is checked for memory leaks prior to releases to CRAN using ASAN/UBSAN. Dissemination is handled by CRAN. Bugs are reported via the tracker and handled as soon as possible.


The threat model is that a malicious actor would “poison” the package code by adding in elements having nothing to do with the package’s purpose but which would be used for malicious purposes. This is protected against by having the email account of the maintainer—used for verification by CRAN—protected by a physical 2FA device (Yubikey) which is carried by the lead maintainer.