This program calculates rank-width and rank-decompositions. It is based on ideas from "Computing rank-width exactly" by Sang-il Oum, "Sopra una formula numerica" by Ernesto Pascal, "Generation of a Vector from the Lexicographical Index" by B.P. Buckles and M. Lybanon and "Fast additions on masked integers" by Michael D. Adams and David S. Wise.
On today's computers it works quite well up to graph sizes of about 28 nodes.

Assuming that libigraph is installed it can be compiled using e.g. "gcc -O2 --std=c99 -pedantic rw.c simplerw.c -ligraph".

It supports a number of input graph formats; there is an example graph included, for which rank-width and rank-decomposition can be calculated using "./a.out --edgelist igrid".

rw.h / rw.c provide a general mechanism for calculating rank-width and rank-decompositions. simplerw.c provides a simple command-line interface.

