Levels of Routines

The subroutines are classified as follows:

• driver routines, each of which solves a complete problem, for example solving a system of linear equations, or computing the eigenvalues of a real symmetric matrix. Users are recommended to use a driver routine if there is one that meets their requirements. The driver routines are listed in Section 2.2 and documented in Part II.
• computational routines, each of which performs a distinct computational task, for example an LU factorization, or the reduction of a real symmetric matrix to tridiagonal form. Each driver routine calls a sequence of computational routines. Users (especially software developers) may need to call computational routines directly to perform tasks, or sequences of tasks, that cannot conveniently be performed by the driver routines. The computational routines are documented in Part III.
• auxiliary routines, which are primarily for internal use. These are not documented in this book.