HSL (Fortran library)
numerical software library
HSL, originally the Harwell Subroutine Library, is a collection of Fortran 77 and 95 codes that address core problems in numerical analysis. It is primarily developed by the Numerical Analysis Group at the Rutherford Appleton Laboratory with contributions from other experts in the field.
HSL codes are easily recognizable by the format of their names, consisting of two letters followed by two numbers, dating back to early versions of Fortran's limited subroutine name length. The letters denote a broad classification of the problem they solve, and the numbers serve to distinguish different codes. For example, the well known sparse LU code MA28 (superseded by MA48) is a Matrix Algebra code number 28. Fortran 95 codes are differentiated from Fortran 77 codes by the prefix HSL_.
History
Early history
Original development of the Harwell Subroutine Library began in 1963 by Mike Powell and Mike Hopper for internal use on an IBM mainframe at AERE Harwell. Early contributors also included Alan Curtis. With a spreading reputation, the Library was distributed externally for the first time in 1964 upon request. The first library catalog (AERE Report M-1748) was released in 1966.
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This entry incorporates text from “HSL (Fortran library)” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.