RBGL (version 1.48.1)

tsort: topological sort of vertices of a digraph

Description

returns vector of zero-based indices of vertices of a DAG in topological sort order

Usage

tsort(x) # now x assumed to be Bioconductor graph graphNEL

Arguments

x

instance of class graphNEL from Bioconductor graph class

Value

A character vector of vertices in the topological sort sequence.

Details

calls to the topological\_sort algorithm of BGL. will check in BGL whether the input is a DAG and return a vector of zeroes (of length length(nodes(x))) if it is not. Thus this function can be used to check for cycles in a digraph.

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

Examples

 data(FileDep)
 tsind <- tsort(FileDep)
 tsind
 FD2 <- FileDep
 # now introduce a cycle
 FD2 <- addEdge("bar_o", "dax_h", FD2, 1)
 tsort(FD2)