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
startto each node ofg; includesInfwhen 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, Lie-Quan Lee, and Andrew Lumsdaine; (Addison-Wesley, Pearson Education Inc., 2002), xxiv+321pp. ISBN 0-201-72914-8
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])
Community examples
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