# LibSci¶

Cray LibSci is a collection of numerical routines tuned for performance on Cray systems. Most users, on most codes, will find they obtain better performance by using calls to Cray LibSci routines in their applications instead of calls to public domain or user-written versions.

Most LibSci components contain both single-processor and parallel routines optimized specifically to make best use of Cray processors and interconnect architectures. The general components of Cray LibSci are:

• BLAS (Basic Linear Algebra Subroutines)

• CBLAS (C interface to the legacy BLAS)

• BLACS (Basic Linear Algebra Communication Subprograms)

• LAPACK (Linear Algebra routines)

• ScaLAPACK (parallel Linear Algebra routines)

Two libraries unique to Cray are:

• IRT (Iterative Refinement Toolkit) - a library of solvers and tools that provides solutions to linear systems using single-precision factorizations while preserving accuracy through mixed-precision iterative refinement.

• CrayBLAS - a library of BLAS routines autotuned for Cray XC series systems through extensive optimization and runtime adaptation. For further information, see intro_blas3(3s).

Note

Additional details are available in the intro_libsci man pages.

cori\$ man intro_libsci