zfp is a compressed format for representing multidimensional floating-point and integer arrays. zfp provides compressed-array classes that support high throughput read and write random access to individual array elements. zfp also supports serial and parallel (OpenMP and CUDA) compression of whole arrays, e.g., for applications that read and write large data sets to and from disk.

zfp uses lossy but optionally error-bounded compression to achieve high compression ratios. Bit-for-bit lossless compression is also possible through one of zfp's compression modes. zfp works best for 2D, 3D, and 4D arrays that exhibit spatial correlation, such as continuous fields from physics simulations, natural images, regularly sampled terrain surfaces, etc. zfp compression of 1D arrays is possible but generally discouraged.

zfp is freely available as open source and is distributed under a BSD license. zfp is primarily written in C and C++ but also includes Python and Fortran bindings. zfp conforms to various language standards, including C89, C99, C11, C++98, C++11, and C++14, and is supported on Linux, macOS, and Windows.

To download zfp, type:

git clone https://github.com/LLNL/zfp.git

zfp may be built using either CMake or GNU make. To use CMake, type:

cd zfp
mkdir build
cd build
cmake ..
cmake --build . --config Release
ctest

This builds the zfp library in the build/lib directory and the zfp command-line executable in the build/bin directory. It then runs the regression tests. The full test suite may be run by enabling the BUILD_TESTING_FULL CMake option during the build step.

zfp may also be built using GNU make:

cd zfp
make
make test

Note: GNU builds are less flexible and do not support all available features, e.g., CUDA support.

For further configuration and build instructions, please consult the documentation. For examples of how to call the C library and use the C++ array classes, see the examples section.

Full HTML documentation is available online. A PDF version is also available.

Further information on the zfp software is included in these files:

• Change log: see CHANGELOG.md.
• Support and additional resources: see SUPPORT.md.
• Code contributions: see CONTRIBUTING.md.

zfp was originally developed by Peter Lindstrom at Lawrence Livermore National Laboratory. Please see the Contributors Page for a full list of contributors.

If you use zfp for scholarly research, please cite this paper:

• Peter Lindstrom. Fixed-Rate Compressed Floating-Point Arrays. IEEE Transactions on Visualization and Computer Graphics, 20(12):2674-2683, December 2014. doi:10.1109/TVCG.2014.2346458.

The algorithm implemented in the current version of zfp is described in the documentation and in the following paper:

• James Diffenderfer, Alyson Fox, Jeffrey Hittinger, Geoffrey Sanders, Peter Lindstrom. Error Analysis of ZFP Compression for Floating-Point Data. SIAM Journal on Scientific Computing, 41(3):A1867-A1898, June 2019. doi:10.1137/18M1168832.

zfp is distributed under the terms of the BSD 3-Clause license. See LICENSE and NOTICE for details.

SPDX-License-Identifier: BSD-3-Clause

LLNL-CODE-663824