Sparse BLAS Workshop 2026

The standardization of an interface for dense linear algebra operations in the BLAS standard has enabled interoperability between different linear algebra libraries, thereby boosting the success of scientific computing, in particular in scientific HPC. In particular, from this point on, applications could interface highly optimized implementations through a standardized API. Despite numerous efforts in the past, the community has not yet agreed on a standardization for sparse linear algebra operations due to numerous reasons. One is the fact that sparse linear algebra objects allow for many different storage formats, and different hardware may favor different storage formats. This makes the definition of a FORTRAN-style all-circumventing interface extremely challenging. Another reason is that opposed to dense linear algebra functionality, in sparse linear algebra, the size of the sparse data structure for the operation result is not always known prior to the information. Furthermore, as opposed to the standardization effort for dense linear algebra, we are late in the technology readiness cycle, and many production-ready software libraries using sparse linear algebra routines have implemented and committed to their own sparse BLAS interface. At the same time, there exists a demand for standardization that would improve interoperability, and sustainability, and allow for easier integration of building blocks. In an inclusive, cross-institutional effort involving numerous academic institutions, US National Labs, and industry, we spent two years designing a hardware-portable interface for basic sparse linear algebra functionality that serves the user needs and is compatible with the different interfaces currently used by different vendors. Defining an interface is an iterative process, and in this third edition of the workshop on defining an interface for sparse linear algebra functionality, we focus on the experience and feedback from the community in terms of adopting the interface we proposed in November 2024. This includes discussing how the set of functionality needs to be adopted or expanded to meet user needs. We also plan a hackathon-style coding session focusing on the wrapping of existing libraries into the proposed interface.

Topics to be covered include but are not limited to:

• Feedback and experience with the proposed sparse BLAS standard

• Experiences wrapping existing functionality into the proposed interface

• Extensions of the scope in terms of functionality and programming languages

• Algorithm implementation discussions

Defining an API standard for sparse linear algebra functionality is a community effort. If you are interested in participating in the discussions and the workshop, please reach out to hanzt@icl.utk.edu.

Hartwig Anzt