= gfan =

== Description ==

Gfan is a software package for computing Groebner fans and tropical varieties.
These are polyhedral fans associated to polynomial ideals. The maximal cones
of a Groebner fan are in bijection with the marked reduced Groebner bases of
its defining ideal. The software computes all marked reduced Groebner bases of
an ideal. Their union is a universal Groebner basis. The tropical variety of a
polynomial ideal is a certain subcomplex of the Groebner fan. Gfan contains
algorithms for computing this complex for general ideals and specialized
algorithms for tropical curves, tropical hypersurfaces and tropical varieties
of prime ideals. In addition to the above core functions the package contains
many tools which are useful in the study of Groebner bases, initial ideals and
tropical geometry. The full list of commands can be found in Appendix B of the
manual. For ordinary Groebner basis computations Gfan is not competitive in
speed compared to programs such as CoCoA, Singular and Macaulay2.

== License ==

 * GPL version 2 or version 3 (according to the gfan website)

== Upstream Contact ==

Anders Nedergaard Jensen; for contact info check out
http://home.imf.au.dk/jensen/software/gfan/gfan.html

== Dependencies ==

 * GMP/MPIR
 * CDDLIB

== Special Update/Build Instructions ==

Remove the doc, homepage, and examples subdirectories, which take up
most of the space.
