LINPACK

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LINPACK is a software library for performing numerical linear algebra on digital computers. It was written in Fortran by Jack Dongarra, Jim Bunch, Cleve Moler, and Gilbert Stewart, and was intended for use on supercomputers in the 1970s and early 1980s. It has been largely superseded by LAPACK, which will run more efficiently on modern architectures.

LINPACK makes use of the BLAS (Basic Linear Algebra Subprograms) libraries for performing basic vector and matrix operations.

The LINPACK Benchmarks are a measure of a system's floating point computing power. Introduced by Jack Dongarra, they measure how fast a computer solves a dense N by N system of linear equations Ax = b, which is a common task in engineering. The solution is obtained by Gaussian elimination with partial pivoting, with 2/3·N³ + 2·N² floating point operations. The result is reported in millions of floating point operations per second (MFLOP/s, sometimes simply called FLOPS).

For large-scale distributed-memory systems, HPL, a portable implementation of the High-Performance LINPACK Benchmark, is used as a performance measure for ranking supercomputers in the TOP500 list of the world's fastest computers. (There is now also a Green500 list ranking the machines on the TOP500 list based on energy efficiency, in FLOPs per Watt.) The HPC benchmark is run for different matrix sizes N searching for the size N_max for which the maximal performance R_max is obtained. The benchmark also reports the problem size N_1/2 where half of the performance (R_max/2) is achieved.

One of the time-consuming routines in Linpack is SAXPY. Computer architects design systems to optimize SAXPY so as to obtain a higher Linpack score.

External links

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• http://www.netlib.org/linpack/
• http://www.netlib.org/blas/
• http://www.top500.org/ Top500
• http://www.netlib.org/benchmark/linpackjava/ a web-based LINPACK benchmark
• http://www.netlib.org/benchmark/hpl/ The HPL benchmark used in the TOP500
• Source code, pre-compiled versions and results for PCs