NAME

       dijkstra - single-source distance filter

SYNOPSIS

       dijkstra [ -adp?  ] [ sourcenode file ]

DESCRIPTION

       dijkstra reads a stream of graphs and for each computes the distance of every node from sourcenode.  Edge
       length  is  given in the len attribute, and the default is 1.  The dist attribute of every node is set to
       its distance from sourcenode.  If the -p flag is used, the prev attribute of  each  node  reachable  from
       sourcenode  is  set  to the name of the previous node on a shortest path.  The graph attribute maxdist is
       set to the maximum dist of all nodes in the graph.

       If the -d flag is used, the graph is treated as directed and only forward edges are used.

       By default, if the graph is disconnected, the dist attribute of nodes  unreachable  from  sourcenode  are
       left untouched, and maxdist is set to the maximum of any previous value and the largest distance recorded
       in  this  run.  On  the  other hand, if the -a flag is used, the dist attribute of an unreachable node is
       assigned a very large value, and maxdist records the maximum distance found in the  component  containing
       sourcenode.

       Any  number  of  sourcenode  file  pairs  may be given.  If the last file is missing, stdin is used.  All
       output is written to stdout.

       In a typical application, dist and maxdist can drive a downstream calculation  of  color  or  some  other
       attribute.

SEE ALSO

       gvpr(1), gvcolor(1), libgraph(3)

                                                  21 March 2001                                      DIJKSTRA(1)