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HSL 2023

The year 2023 marks the 60th anniversary of the first release in 1963 of what was then the Harwell Subroutine Library. Although originally a general-purpose mathematical library, in recent times HSL has specialised in providing state-of-the-art routines for handling large-scale sparse matrix calculations efficiently and reliably. Jennifer Scott has produced a brief historical account of HSL@60.

Highlights of HSL 2023 include:

HSL 2023 is freely available to academic staff and students for personal use in teaching and research. Commercial licences are also available. You can download individual pacakages from the HSL Catalogue.

We hope you enjoy using HSL2023, and welcome any feedback or suggestions at

The HSL Team
Tyrone Rees, Jennifer Scott, Andrew Lister, Jaroslav Fowkes, Hussam Al Daas, Niall Bootland, Iain Duff, Jessica Farmer, John Reid, Nick Gould, Alexis Montoison.

Full release notes

New codes

Major updates

Minor updates