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Finding all the elementary circuits of a directed graph
-------------------------------------------------------
Algorithm by D. B. Johnson
Finding all the elementary circuits of a directed graph.
D. B. Johnson, SIAM Journal on Computing 4, no. 1, 77-84, 1975.
http://dx.doi.org/10.1137/0204007
Functional and iterative version.
Additional code available at http://mancoosi.org/~abate/finding-all-elementary-circuits-directed-graph
Original git repository at http://mancoosi.org/~abate/repos/cycles.git
The original code was faulty. This version is fixed for the functional as well
as the iterative version.
Usage
-----
make
./cycles_{iter,functional}.native 4 0,1 0,2 1,0 1,3 2,0 3,0 3,1 3,2
First argument is the number of vertices. Subsequent arguments are ordered
pairs of comma separated vertices that make up the directed edges of the
graph.
DOT file input
--------------
For simplicity, there is no DOT file parser included but the following allows
to create a suitable argument string for simple DOT graphs.
Given a DOT file of a simple (no labels, colors, styles, only pairs of
vertices...) directed graph, the following line produces commandline
arguments in the above format for that graph.
echo `sed -n -e '/^\s*[0-9]\+;$/p' graph.dot | wc -l` `sed -n -e 's/^\s*\([0-9]\) -> \([0-9]\);$/\1,\2/p' graph.dot`
The above line works on DOT files like the following:
digraph G {
0;
1;
2;
0 -> 1;
0 -> 2;
1 -> 0;
2 -> 0;
2 -> 1;
}
It would produce the following output:
3 0,1 0,2 1,0 2,0 2,1