RAJA is a collection of C++ software abstractions, being developed at
Lawrence Livermore National Laboratory (LLNL), that enable architecture
portability for HPC applications. The overarching goals of RAJA are to:
- Make existing (production) applications portable with minimal disruption
- Provide a model for new applications so that they are portable from
inception.
RAJA uses standard C++11 -- C++ is the predominant programming language in
which many LLNL codes are written. RAJA is rooted in a perspective based on
substantial experience working on production mesh-based multiphysics
applications at LLNL. Another goal of RAJA is to enable application developers
to adapt RAJA concepts and specialize them for different code implementation
patterns and C++ usage, since data structures and algorithms vary widely
across applications.
RAJA shares goals and concepts found in
other C++ portability abstraction approaches, such as
Kokkos
and Thrust.
However, it includes concepts that are absent in other models and which are
fundamental to LLNL codes.
It is important to note that RAJA is very much a work-in-progress.
The community of researchers and application developers at LLNL that are
actively contributing to it and developing new capabilities is growing.
The publicly-released version contains only core pieces of RAJA as they
exist today. While the basic interfaces are fairly stable, the implementation
of the underlying concepts is being refined. Additional features will appear
in future releases.
Quick Start
The RAJA code lives in a GitHub repository.
To clone the repo, use the command:
git clone --recursive https://github.com/llnl/raja.git
Then, you can build RAJA like any other CMake project, provided you have a C++
compiler that supports the C++11 standard. The simplest way to build the code,
using your system default compiler, is to run the following sequence of
commands in the top-level RAJA directory (in-source builds are not allowed!):
mkdir build
cd build
cmake ../
make
More details about RAJA configuration options are located in the User
Documentation.
We also maintain a RAJA Template Project that shows how to use RAJA in a CMake project, either as a Git
submodule or as an installed library.
User Documentation
The RAJA User Guide and Tutorial
is the best place to start learning about RAJA and how to use it.
To cite RAJA, please use the following references:
-
RAJA Performance Portability Layer. https://github.com/LLNL/RAJA
-
D. A. Beckingsale, J. Burmark, R. Hornung, H. Jones, W. Killian, A. J. Kunen, O. Pearce, P. Robinson, B. S. Ryujin, T. R. W. Scogland, "RAJA: Porrtable Performance for Large-Scale Scientific Applications", 2019 IEEE/ACM International Workshop on Performance, Portability and Productivity in HPC (P3HPC). Download here
Related Software
The RAJA Performance Suite contains
a collection of loop kernels implemented in multiple RAJA and non-RAJA
variants. We use it to monitor and assess RAJA performance on different
platforms using a variety of compilers.
The RAJA Proxies repository
contains RAJA versions of several important HPC proxy applications.
CHAI provides a managed array abstraction
that works with RAJA to automatically copy data used in RAJA kernels to the
appropriate space for execution. It was developed as a complement to RAJA.
Mailing List
Interested in keeping up with RAJA or communicating with its developers and
users? Please join our mailing list at Google Groups:
If you have questions, find a bug, or have ideas about expanding the
functionality or applicability of RAJA and are interested in contributing
to its development, please do not hesitate to contact us. We are very
interested in improving RAJA and exploring new ways to use it.
Contributions
The RAJA team follows the GitFlow development model. Folks wishing to contribute to RAJA, should
include their work in a feature branch created from the RAJA develop branch.
Then, create a pull request with the develop branch as the destination. That
branch contains the latest work in RAJA. Periodically, we will merge the
develop branch into the master branch and tag a new release.
Authors
The original developers of RAJA are:
- Rich Hornung (hornung1@llnl.gov)
- Jeff Keasler (keasler1@llnl.gov)
Please see the RAJA Contributors Page, to see the full list of contributors to the project.
License
RAJA is licensed under the BSD 3-Clause license,
(BSD-3-Clause or https://opensource.org/licenses/BSD-3-Clause).
Copyrights and patents in the RAJA project are retained by contributors.
No copyright assignment is required to contribute to RAJA.
Unlimited Open Source - BSD 3-clause Distribution
LLNL-CODE-689114 OCEC-16-063
For release details and restrictions, please see the information in the
following:
SPDX usage
Individual files contain SPDX tags instead of the full license text.
This enables machine processing of license information based on the SPDX
License Identifiers that are available here: https://spdx.org/licenses/
Files that are licensed as BSD 3-Clause contain the following
text in the license header:
SPDX-License-Identifier: (BSD-3-Clause)
External Packages
RAJA bundles its external dependencies as submodules in the git repository.
These packages are covered by various permissive licenses. A summary listing
follows. See the license included with each package for full details.
PackageName: BLT
PackageHomePage: https://github.com/LLNL/blt
PackageLicenseDeclared: BSD-3-Clause
PackageName: camp
PackageHomePage: https://github.com/LLNL/camp
PackageLicenseDeclared: BSD-3-Clause
PackageName: CUB
PackageHomePage: https://github.com/NVlabs/cub
PackageLicenseDeclared: BSD-3-Clause