cheddar (version 0.1-636)

ShortestPaths: Path lengths

Description

Functions that compute the shortest trophic paths between nodes.

Usage

ShortestPaths(community, weight.by=NULL)
CharacteristicPathLength(community)

Arguments

community

an object of class Community.

weight.by

the name of a property by which to weight paths.

Value

A square matrix with NumberOfNodes rows and columns or a single number.

Details

ShortestPaths uses Dijkstra's algorithm to compute the number of trophic links between each pair of nodes in the food web. CharacteristicPathLength returns the mean of path lengths.

References

Williams, R.J. and Berlow, E.L. and Dunne, J.A. and Barab\'asi, A.L. and Martinez, N.D. (2002) Two degrees of separation in complex food webs. Proceedings of the National Academy of Sciences of the United States of America 99, 20, 12913--12916

See Also

PredationMatrix, NPS

Examples

# NOT RUN {
data(Benguela)

# Compare weighted and unweighted
ShortestPaths(Benguela)
ShortestPaths(Benguela, weight.by='diet.fraction')

CharacteristicPathLength(Benguela)
# }