Elsevier Science Home
Computer Physics Communications Program Library
Full text online from Science Direct
Programs in Physics & Physical Chemistry
CPC Home

[Licence| Download | New Version Template] abhy_v1_0.gz(517 Kbytes)
Manuscript Title: epicGRASS: symbolic calculations with anticommuting variables.
Authors: U. Hartmann, E.D. Davis
Program title: EGRASS
Catalogue identifier: ABHY_v1_0
Distribution format: gz
Journal reference: Comput. Phys. Commun. 54(1989)353
Programming language: Fortran.
Computer: VAX.
Operating system: VAX/VMS.
RAM: 500K words
Word size: 32
Keywords: General purpose, Matrix, Computer algebra, Grassmann integration, Anticommuting variables, Algebraic calculation, Interactively.
Classification: 4.8, 5.

Nature of problem:
The super-mathematics, in which commuting and anticommuting variables are treated on equal footing, is used frequently in random matrix theories. The need for this program arose, when very lengthy calculations involving several thousands of terms had to be performed.

Solution method:
The algebra of the anticommuting variables is "hardwired" with the help of a table.

Unusual features:
The computations are exact, free of numerical approximation. Special, normally not available commands and functions are implemented to investigate the structure of graded matrices. An expression given may contain any arbitrary (sensible) combination of valid operations. The program may be operated interactively or in batch mode and provides on- line help for the syntax and will give sophisticated error messages.

Running time:
Varies widely, depending on the complexity of the data. Typically (VAX 8650) for matrix expressions containing 200 terms some seconds, for matrix expressions containing 5000 terms several minutes.