acyclic - make directed graph acyclic
acyclic [ -nv? ] [ -o outfile ] [ file ]
acyclic is a filter that takes a directed graph as input and outputs a
copy of the graph with sufficient edges reversed to make the graph acyclic.
The reversed edge inherits all of the attributes of the original edge. The
optional file argument specifies where the input graph is stored; by default,
the program reads from stdin.
The following options are supported:
acyclic returns 0 if the graph is acyclic; 1 if the graph
has a cycle; 2 if the graph is undirected; and 255 if there are
If the graph is strict and there is a cycle of length 2, the attributes of the
reversed edge are lost.
- No output is produced, though the return value will indicate whether the
graph is acyclic or not.
- Print information about whether the file is acyclic, has a cycle or is
- -o outfile
- causes the output to be written to the specified file; by default, output
is written to stdout.
- option causes the program to print usage information.
Some edge attributes are non-symmetric, referring to either the
head or tail node. At present, there is no mechanism or convention for
correctly switching or renaming these.
Stephen C. North <email@example.com>
Emden R. Gansner <firstname.lastname@example.org>
gc(1), dot(1), gvpr(1), gvcolor(1), ccomps(1), sccmap(1), tred(1), libgraph(3)