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67 lines
1.6 KiB
Groff
67 lines
1.6 KiB
Groff
.TH DIJKSTRA 1 "21 March 2001"
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.SH NAME
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dijkstra \- single-source distance filter for Graphviz
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.SH SYNOPSIS
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.B dijkstra
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[
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.B \-adp?
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]
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[
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.I sourcenode file
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]
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.SH DESCRIPTION
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.B dijkstra
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reads a stream of Graphviz formatted graphs and for each computes the distance of every node from
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.I sourcenode.
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Edge length is given in the
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.I len
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attribute, and the default is 1. The
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.I dist
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attribute of every node is set to its distance from
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.I sourcenode.
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If the \fB-p\fP flag is used, the
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.I prev
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attribute of each node reachable from
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.I sourcenode
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is set to the name of the previous node on a shortest path.
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The graph attribute
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.I maxdist
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is set to the maximum
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.I dist
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of all nodes in the graph.
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.P
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If the \fB-d\fP flag is used, the graph is treated as directed and
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only forward edges are used.
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.P
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By default, if the graph is disconnected, the
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.I dist
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attribute of nodes unreachable from
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.I sourcenode
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are left untouched, and
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.I maxdist
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is set to the maximum of any previous value and the largest
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distance recorded in this run. On the other hand, if
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the \fB-a\fP flag is used, the
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.I dist
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attribute of an unreachable node is assigned a very large value,
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and
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.I maxdist
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records the maximum distance found in the component containing
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.I sourcenode.
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.P
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Any number of
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.I sourcenode file
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pairs may be given.
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If the last
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.I file
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is missing, \fBstdin\fP is used.
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All output is written to \fBstdout\fP.
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.P
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In a typical application,
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.I dist
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and
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.I maxdist
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can drive a downstream calculation of color or some other attribute.
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.SH "SEE ALSO"
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gvpr(1), gvcolor(1), libgraph(3)
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