package owl

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OCaml Scientific and Engineering Computing


Dune Dependency






Owl: OCaml Scientific and Engineering Computing

Owl is an OCaml numerical library. It supports N-dimensional arrays, both dense and sparse matrix operations, linear algebra, regressions, fast Fourier transforms, and many advanced mathematical and statistical functions (such as Markov chain Monte Carlo methods). Recently, Owl has implemented algorithmic differentiation which essentially makes developing machine learning and neural network algorithms trivial.

Published: 02 Mar 2023


Owl - OCaml Scientific Computing

Owl is a dedicated system for scientific and engineering computing. The system is developed in OCaml and licensed under MIT. The project is led by Liang Wang. The history of the project is on the Wikipedia.


We would like to express our sincerest gratitude for our sponsors' generosity. The support is critical for Owl's development and maintenance, so the OCaml community can benefit from a strong numerical library. If you are interested in sponsorship, please contact me or donate via PayPal.


Roles and Responsibilities


The Owl Project follows a BDFL (Benevolent Dictator for Life) governance model. The BDFL consists of Liang Wang and Jianxin Zhao. Liang is the project originator of and project leader of Owl. Jianxin worked on the project for his PhD thesis. He is currently managing daily practicalities of the project. The BDFL are in charge of setting out the roadmap and maintaining the architecture of Owl. In principle, only the BDFL has write permission to the code base.


The project is developed and maintained by a team of contributors. A contributor is an individual who contributes code, documentation, or who helps with the management, event organisation, financing, etc. of the project. Anyone can potentially become a contributor given sufficient contributions recognised by the community. Contributors can be affiliated with any legal entity or none.

A subset of the code contributors are the committers, who have proved to make several valuable and significant contributions to the project in both quality and quantity. Typically a committer focuses on one specific aspect of the project and is a domain expert. In principle any change to the code base is made via a GitHub Pull Request (PR). A committer can request temporary write permission to the code base from the BDFL when it can be justified, such as frequent updates are required in a short period of time. The permission shall be revoked once the necessary job is done. The committers have no explicit authority over the project, but the BDFL should heed their counsel in making project decisions. In practice, they are given informal control over their specific areas of expertise.

Owl Team

The BDFL has the authority to make all final decisions for the project. In practice, the BDFL tries to reach a consensus within the Owl Team. The Owl Team consists of the BDFL and a small subset of the project contributors who have produced contributions that are of outstanding quality and quantity, and have actively participated in the Owl project for at least two years. The team structure is dynamic with members joining or leaving.


The development of Owl includes adding new functionalities and fixing bugs in the form of PR from the contributors. In order to be merged, a PR must be reviewed and acquire two approvals from the Owl Team. If a PR is large or involves significant changes to the code structure, it requires the review of the BDFL. A wide-open discussion from all contributors about the PR is encouraged. A BDFL accepts the PR once the reviewers approve it and the team decides that this PR is sufficiently discussed. When enough PRs are accumulated, a new version should be released. A new release should be discussed within the Owl team and approved by the BDFL.


Owl originated from academia. To this day, many of our core contributors have academic positions and active research programs. The subprojects are listed at the project website. We welcome anyone to discuss potential research proposals with the team. A research project based on Owl should be explicitly made known to all team members, and provides a clear attribute to Owl.


The current community of Owl is based on the Slack channel. All participants in the community are encouraged to provide support for new users within the project management infrastructure. Those seeking technical support should also recognise that all support activities within the project is voluntary and is therefore provided as and when time permits.

Dependencies (10)

  1. npy
  2. stdio build
  3. owl-base = version
  4. dune-configurator
  5. dune >= "2.0.0"
  6. ctypes >= "0.16.0"
  7. conf-openblas >= "0.2.1"
  8. base-bigarray
  9. base build
  10. ocaml >= "4.10.0"

Dev Dependencies (1)

  1. alcotest with-test

Used by (9)

  1. gobba >= "0.4.2"
  2. molenc = "11.4.0"
  3. owl-ode >= "0.4.0"
  4. owl-ode-odepack != "0.3.0"
  5. owl-ode-sundials != "0.3.0"
  6. owl-opt
  7. owl-opt-lbfgs
  8. owl-plplot < "0.8.0"
  9. owl-top < "0.8.0" | >= "1.1"




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