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)