igraph (version 1.2.3)

strength: Strength or weighted vertex degree

Description

Summing up the edge weights of the adjacent edges for each vertex.

Usage

strength(graph, vids = V(graph), mode = c("all", "out", "in", "total"),
  loops = TRUE, weights = NULL)

Arguments

graph

The input graph.

vids

The vertices for which the strength will be calculated.

mode

Character string, “out” for out-degree, “in” for in-degree or “all” for the sum of the two. For undirected graphs this argument is ignored.

loops

Logical; whether the loop edges are also counted.

weights

Weight vector. If the graph has a weight edge attribute, then this is used by default. If the graph does not have a weight edge attribute and this argument is NULL, then a warning is given and degree is called.

Value

A numeric vector giving the strength of the vertices.

References

Alain Barrat, Marc Barthelemy, Romualdo Pastor-Satorras, Alessandro Vespignani: The architecture of complex weighted networks, Proc. Natl. Acad. Sci. USA 101, 3747 (2004)

See Also

degree for the unweighted version.

Examples

# NOT RUN {
g <- make_star(10)
E(g)$weight <- seq(ecount(g))
strength(g)
strength(g, mode="out")
strength(g, mode="in")

# No weights, a warning is given
g <- make_ring(10)
strength(g)
# }