dijkstra.sp
Dijkstra's shortest paths using boost C++
dijkstra's shortest paths
 Keywords
 graphs
Usage
dijkstra.sp(g,start=nodes(g)[1], eW=unlist(edgeWeights(g)))
Arguments
 g
 instance of class graph
 start
 character: node name for start of path
 eW
 numeric: edge weights.
Details
These functions are interfaces to the Boost graph library C++ routines for Dijkstra's shortest paths.
For some graph subclasses, computing the edge weights can be expensive.
If you are calling dijkstra.sp
in a loop, you can pass the edge
weights explicitly to avoid the edge weight creation cost.
Value

A list with elements:
 distance
 The vector of distances from
start
to each node ofg
; includesInf
when there is no path fromstart
.  penult
 A vector of indices
(in
nodes(g)
) of predecessors corresponding to each node on the path from that node back tostart
. For example, if the
element one of this vector has value  start
 The start node that was supplied in the call to
dijkstra.sp
.
10
, that means that the
predecessor of node 1
is node 10
. The next predecessor is
found by examining penult[10]
.
References
Boost Graph Library ( www.boost.org/libs/graph/doc/index.html )
The Boost Graph Library: User Guide and Reference Manual; by Jeremy G. Siek, LieQuan Lee, and Andrew Lumsdaine; (AddisonWesley, Pearson Education Inc., 2002), xxiv+321pp. ISBN 0201729148
See Also
Examples
con1 < file(system.file("XML/dijkex.gxl",package="RBGL"), open="r")
dd < fromGXL(con1)
close(con1)
dijkstra.sp(dd)
dijkstra.sp(dd,nodes(dd)[2])
con2 < file(system.file("XML/ospf.gxl",package="RBGL"), open="r")
ospf < fromGXL(con2)
close(con2)
dijkstra.sp(ospf,nodes(ospf)[6])
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