strength {igraph} | R Documentation

## 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.

### Author(s)

Gabor Csardi csardi.gabor@gmail.com

### 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

    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)

[Package igraph version 1.1.2 Index]