Kokkos: Core Libraries

Kokkos Core implements a programming model in C++ for writing performance portable applications targeting all major HPC platforms. For that purpose it provides abstractions for both parallel execution of code and data management. Kokkos is designed to target complex node architectures with N-level memory hierarchies and multiple types of execution resources. It currently can use CUDA, HIP, SYCL, HPX, OpenMP and C++ threads as backend programming models with several other backends in development.

Kokkos Core is part of the Kokkos C++ Performance Portability Programming Ecosystem.

Kokkos is a Linux Foundation project.

Learning about Kokkos

To start learning about Kokkos:

• Kokkos Lectures: they contain a mix of lecture videos and hands-on exercises covering all the important capabilities.

• Programming guide: contains in "narrative" form a technical description of the programming model, machine model, and the main building blocks like the Views and parallel dispatch.

• API reference: organized by category, i.e., core, algorithms, containers, and simd.

• Use cases and Examples: a series of examples ranging from how to use Kokkos with MPI to Fortran interoperability.

Obtaining Kokkos

The latest release of Kokkos can be obtained from the GitHub releases page.

The current release is 5.1.0.

curl -OJ -L https://github.com/kokkos/kokkos/releases/download/5.1.0/kokkos-5.1.0.tar.gz
# Or with wget
wget https://github.com/kokkos/kokkos/releases/download/5.1.0/kokkos-5.1.0.tar.gz
# Or with git
git clone --depth=2 --branch 5.1.0 https://github.com/kokkos/kokkos.git

To clone the latest development version of Kokkos from GitHub:

git clone --branch develop  https://github.com/kokkos/kokkos.git

Building Kokkos

To build Kokkos, you will need to have a C++ compiler that supports C++20 or later. All requirements including minimum and primary tested compiler versions can be found here.

Building and installation instructions are described here.

You can also install Kokkos using Spack: spack install kokkos. Available configuration options can be displayed using spack info kokkos.

For the complete documentation: kokkos.org/kokkos-core-wiki/

Support

For questions find us on Slack: https://kokkosteam.slack.com or open a GitHub issue.

For non-public questions send an email to: crtrott(at)sandia.gov

Contributing

Please see this page for details on how to contribute.

Citing Kokkos

Please see the following page.

License

The full license statement used in all headers is available here or here.

The repository follows the REUSE specification: every file carries an SPDX license identifier, either in the file itself or in REUSE.toml. The LICENSES directory contains the verbatim text of each license referenced by those identifiers:

• Apache-2.0.txt and LLVM-exception.txt: the license of Kokkos itself (Apache-2.0 WITH LLVM-exception), as reproduced in the top-level LICENSE.
• BSD-3-Clause.txt: the license of bundled third-party code (tpls/desul and tpls/googletest-*).

The top-level LICENSE file remains the authoritative statement for Kokkos. Compliance can be checked with reuse lint.