find all circuits of a directed graph using johnson's algorithm and java implementation by frank meyer
Clone or download
Latest commit e666dad Apr 11, 2013
Permalink
Type Name Latest commit message Commit time
Failed to load latest commit information.
de/normalisiert/utils/graphs read edges from stdin instead of argv Apr 11, 2013
Makefile add Makefile and adjust output format Jul 3, 2012
README.md some fixes in the README Apr 11, 2013

README.md

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

Usage

make
echo "0 1\n0 2\n1 0\n1 3\n2 0\n3 0\n3 1\n3 2" | java de.normalisiert.utils.graphs.TestCycles 4

First argument is the number of vertices. Ordered pairs of space separated vertices are given via standard input and 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 and standard input for simple DOT graphs.

Given a DOT file of a simple (no labels, colors, styles, only pairs of vertices...) directed graph, the following lines generate the number of vertices as well as the edge list expected on standard input.

    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 lines work on DOT files like the following:

digraph G {
  0;
  1;
  2;
  0 -> 1;
  0 -> 2;
  1 -> 0;
  2 -> 0;
  2 -> 1;
  }

They would produce the following output:

3
0 1
0 2
1 0
2 0
2 1