ACYCLIC(1) ACYCLIC(1)
NAME
acyclic - make directed graph acyclic
SYNOPSIS
acyclic [ -nv? ] [ -o outfile ] [ file(1,n) ]
DESCRIPTION
acyclic is a filter(1,3x,3x curs_util) 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 origi-
nal edge. The optional file(1,n) argument specifies where the the input
graph is stored; by default, the program reads from stdin.
OPTIONS
The following options are supported:
-n No output is produced, though the return value will indicate
whether the graph is acyclic or not.
-v Print information about whether the file(1,n) is acyclic, has a cycle
or is undirected.
-o outfile
causes the output to be written to the specified file(1,n); by
default, output is written to stdout.
-? option causes the program to print usage information.
RETURN CODES
acyclic returns 0 if(3,n) the graph is acyclic; 1 if(3,n) the graph has a cycle;
2 if(3,n) the graph is undirected; and 255 if(3,n) there are any errors.
BUGS
If the graph is strict and there is a cycle of length 2, the attributes
of the reversed edge are lost.
Some edge attributes are non-symmetric, referring to either the head or
tail node. At present, there is no mechanism or convention for for cor-
rectly switching or renaming these.
AUTHORS
Stephen C. North <north@research.att.com>
Emden R. Gansner <erg@research.att.com>
SEE ALSO
gc(1), dot(1), gvpr(1), gvcolor(1), ccomps(1), sccmap(1), tred(1), lib-
graph(3)
21 March 2001 ACYCLIC(1)