What's new (past 12 months)

Version 3.6.5 available

Version 3.5.2 available

qgraf
latest version:  3.6.5

Qgraf is a computer program that generates Feynman diagrams for various types of QFT models — it is a research tool created with the obvious aim of contributing to extend the range of feasible, perturbative QFT calculations. It generates neither 0-point nor non-connected diagrams, though. Diagrams are represented by symbolic expressions only; if some kind of graphical representation is required, however, have a look at some of the external links (in the first group).

  • Latest version: qgraf-3.6.5 (October 2022).
    Please report any error you may happen to find.

  • Programming language: Fortran 2008 for versions released since 2020 (qgraf-3.5+), and Fortran 77 for earlier versions.
    Executables/binaries are not distributed, the program has to be compiled and linked.
    Employing GNU Fortran for that task should be straightforward, eg there should be no need to specify a Fortran standard (see eg file qgraf-3.6.5.pdf).
    There are executable/binary versions of GFortran for several operating systems, as described in the GFortranBinaries webpage.

  • The features added in the last three versions include (eg):
    selecting 1–vertex irreducible diagrams (3.4);
    selecting diagrams with non-factorizable cycle spaces (3.4);
    generating multiple output files in the same run (3.5);
    inputing simple command-line arguments (3.5);
    an extended language for describing input models (3.6);
    a more general loops statement (3.6).

  • Current plans: qgraf-3.4 should be available and supported for some time yet (minimal fixes as need be); qgraf-3.6 should be declared stable by December 01, with the features available in qgraf-3.6.5, unless some unresolved serious issue exists at that time (leaving the Fortran and C interfaces to qgraf-3.7, in 2023, seems to be preferable).

Qgraf is based on the method described in the following paper:

  • Automatic Feynman graph generation
    J. Comput. Phys. 105 (1993) 279–289
    https://doi.org/10.1006/jcph.1993.1074

    show outline

The diagram generation with explicitly mixed propagators (kinetic mixing) can be reduced to the usual one:

  • Feynman graph generation and propagator mixing, I
    Comput. Phys. Commun. 269 (2021) 108103
    https://doi.org/10.1016/j.cpc.2021.108103

    show outline