In weighted graphs, a real number is assigned to each (directed or undirected) edge.
- The input graph.
In igraph edge weights are represented via an edge attribute, called
is.weighted function only checks that such
an attribute exists. (It does not even checks that it is a numeric edge
Edge weights are used for different purposes by the different functions. E.g. shortest path functions use it as the cost of the path; community finding methods use it as the strength of the relationship between two vertices, etc. Check the manual pages of the functions working with weighted graphs for details.
- A logical scalar.
g <- graph.ring(10) get.shortest.paths(g, 8, 2) E(g)$weight <- seq_len(ecount(g)) get.shortest.paths(g, 8, 2)