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168.wupwise
SPEC CPU2000 Benchmark Description File


Benchmark Name

168.wupwise


Benchmark Authors

Bjoern Medeke (medeke@math.uni-wuppertal.de)
Institute of Applied Computer Science
University of Wuppertal
Gauss-Strasse 20
D-42097 Wuppertal
Germany


Benchmark Program General Category

Physics / Quantum Chromodynamics


Benchmark Description

"wupwise" is an acronym for "Wuppertal Wilson Fermion Solver", a program in the area of lattice gauge theory (quantum chromodynamics).

Lattice gauge theory is a discretization of quantum chromodynamics which is generally accepted to be the fundamental physical theory of strong interactions among the quarks as constituents of matter. The most time-consuming part of a numerical simulation in lattice gauge theory with Wilson fermions on the lattice is the computation of quark propagators within a chromodynamic background gauge field. These computations use up a major part of the world's high performance computing power.

Quark propagators are obtained by solving the inhomogeneous lattice-Dirac equation. The Wuppertal Wilson Fermion Solver (wupwise) solves the inhomogeneous lattice-Dirac equation via the BiCGStab iterative method which has established itself as a method of choice.

A more detailed characterization of the program can be found in the Postscript file "wupwise.ps" in the "docs" subdirectory.


Input Description

The input file wupwise.in contains a few parameters from which the problem is built, among them:

  • SEED seed value for a random number generator which supplies initial data
  • NITER number of iterations
  • KAPPA parameter characterizing the matrix M = I - KAPPA * D



Output Description

The main output file is "wupwise.out", containing a check value (EPS) for each the NITER iterations, and a final value EPSILON characterizing the BiCGStab result.

In addition, there is a file "te.out", containing the value "TRUE EPSILON". Since this value (in the magnitude of 0.6E-5) has been found to vary more between systems, it is written to a separate file for which the SPEC-imposed accuracy requirements are different from those required for the main output file (see values $reltol in file 168.wupwise/Spec/object.pm).


Programming Language

Fortran 77, with the change that (as in all of SPEC's Fortran benchmarks) the type

  DOUBLE PRECISION

has been replaced by

  REAL*8

thus making the size of the relevant floating-point data uniform across systems - an important consideration for fair benchmarking. While the type REAL*8 is not part of the strict FORTRAN77 or Fortran90 standards, it is a common language extension recognized by all Fortran compilers the SPEC CPU subcomittee has used in its tests.


Known portability issues

The source code as prepared by SPEC contains FORTRAN77 versions of common LINPACK BLAS functions (zaxpy.f, zcopy.f, zdotc.f, zgemm.f, zscal.f). According to the CPU2000 Run and Reporting Rules (2.1.2), the level 1, 2, and 3 BLAS functions may be substituted by precomputed (library-based) subroutines (compilation for peak runs only, not for baseline runs). For the case that this is not done (e.g., for baseline runs, or if optimized libraries are not available), all BLAS functions needed by the benchmark are provided in the source directory.

Note that since these source functions were taken unchanged from the respective source code libraries, the spelling of their names has been retained: They are defined in the files z*.f in lower case, but called in upper case. For Fortran compilers that insist on a strict FORTRAN77 standard (which only recognizes upper-case letters in identifiers), a suitable portability flag like

  -fu Convert all lower-case identifiers to uppercase

may be necessary.


Last updated: 8 November 1999