ACYCLIC(1)                                                                                                            ACYCLIC(1)



NAME
       acyclic - make directed graph acyclic

SYNOPSIS
       acyclic [ -nv?  ] [ -o outfile ] [ file ]

DESCRIPTION
       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 argu-
       ment 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 is acyclic, has a cycle or is undirected.

       -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.

RETURN CODES
       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
       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 correctly switching or renaming these.

AUTHORS
       Stephen C. North <northATresearch.com>
       Emden R. Gansner <ergATresearch.com>

SEE ALSO
       gc(1), dot(1), gvpr(1), gvcolor(1), ccomps(1), sccmap(1), tred(1), libgraph(3)



                                                          21 March 2001                                               ACYCLIC(1)