linpack_bench, a C code which carries out the LINPACK Benchmark, which measures the time required to factor and solve a large linear system.
The linpack() benchmark is a test problem used to rate the performance of a computer on a simple linear algebra problem.
The test problem requires the user to set up a random dense matrix A of size N = 1000, and a right hand side vector B which is the product of A and a vector X of all 1's. The first task is to compute an LU factorization of A. The second task is to use the LU factorization to solve the linear system
A * X = B.
The number of floating point operations required for these two tasks is roughly
ops = 2 * N*N*N / 3 + 2 * N * N,therefore, the "MegaFLOPS" rating, or millions of floating point operations per second, can be found as
mflops = ops / ( cpu * 1000000 ).
The C source code presented here is unusual in that a single file embodies both single and double precision. The precision to be used is specified at compile time with a compiler option. Moreover, another compiler option allows the user to request "rolled loops" (the normal kind of for loop), or "unrolled loops", in which the loops are done with an increment greater than 1. The unrolled option can often significantly improve performance.
On a given computer, if you run the benchmark for a sequence of increasing values of N, the behavior of the MegaFLOPS rating will vary as you pass through three main zones of behavior:
| Language | Precision | Type | Machine | Comment | MegaFLOPS |
|---|---|---|---|---|---|
| C | Single | Real | DHCP95 (Apple G5) | rolled | 108 |
| C | Single | Real | DHCP95 (Apple G5) | unrolled | 184 |
| C | Double | Real | DHCP95 (Apple G5) | rolled | 111 |
| C | Double | Real | DHCP95 (Apple G5) | unrolled | 190 |
The information on this web page is distributed under the MIT license.
linpack_bench is available in a C version and a C++ version and a Fortran77 version and a Fortran90 version and a Java version and a MATLAB version and an Octave version and a Python version.
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