DIJKSTRA(1)                 General Commands Manual                DIJKSTRA(1)



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)
