pressio-ops C++ library#
This library aims to provide a unified free-function-based interface to facilitate usability and interoperability of widely-used linear algebra software libraries.
Motivation#
Linear algebra underpins many applications fundamental to science and industry. Currently, there are multiple open-source libraries offering shared- and distributed-memory linear algebra data structures (vectors, matrices, etc.) and/or kernel operations to manipulate them. For example, Trilinos, PETSc, Kokkos/Kokkos-kernels, Eigen, Blitz++, Armadillo, mlpack, BLAS/LAPACK. These libraries serve as foundations to many applications. Compound this mutiplicity of efforts by the lack of interest and/or resources to improve their usability and inteoperabability, and the result is a plethora of linear algebra libraries that shared some key aspects:
diverse API: every library has its own custom API for doing, after all, the same set of operations. This poses a major limitation to existing software stacks relying on them because it inhibits an easy transition to a different choice. What would happen if one of these fundamental libraries were discontinued? It would lead to many applications having to be refactored, a huge investment of resouces and development hours. Also, this constitutes a problem for any new application that will being developed, since one would need to choose one library from the start and stick to it, or reimplemnet support for multiple backends from scratch every time.
hard-to-use API: some of these libraries adopted an API that closely adheres to the BLAS standard, thus making them harder to use for a generic user. It is well-known and accepted that the BLAS standard defines an API is hard to read and use: one reason is that its API defines functions accepting several arguments, with adjacent parameters that can be invoked by the same arguments in either order with different meaning. This makes them hard to be used correctly—this was also a key motivation of the standardization effort that led to the C++26 stdBLAS feature.
hard to extend/customize: in some cases, e.g. Trilinos, the design is such that operations to manipulate data are methods of the data structures classes themselves rather than free fucntions. In C++, such design precludes the flexibility of doing user-level overloading or specialization of these “operations”.
minimal or non-existent interoperability: the intoperability between some of these libraries is minimal or even non-existent. Several factors contributed to this, inlcuding that some of the libraries were intended for heterogenous hardware, while some only work for CPUs; some only operate on a single node while others support distributed memory. This makes it really hard to couple different applications, exchange data, and operated on-line on different data structures.
What pressio-ops offers#
This library tries to address some of issues above by providing a unified free-function-based interface to facilitate usability and interoperability of widely-used linear algebra software libraries. The supported capabilities are shown in the table below. Each component (level) of the stack depends on the ones below it.
Description |
Header(s) |
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shared-memory/distributed linear algebra kernels specializations |
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expressions templates, e.g.: span, diagonal, subspan |
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type traits and detection |
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metaprogramming functionalities |
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Get Started#
Install: (currently) header-only, should be trivial
License and Citation#
The full license (BSD-3) is available here.
Sooner or later we will publish this… in the meantime, you can find on arXiv an (outdated) preprint at: https://arxiv.org/abs/2003.07798
Questions?#
Find us on Slack: https://pressioteam.slack.com or open an issue on github.