I have a dataset of a graph (undirected), represented by the edges. But most of the vertices are not connected.
Supposing the vertex set is
{1,2,3,4,5,6,7,8}
and the edges are just
1->2
2->3
1->3
How do I get the adjacency matrix for this using the igraph package? Using the below code doesnt give the full adjacency as it gets only 3 vertices in the input edgelist
get.adjacency(graph.edgelist(as.matrix(edges), directed=FALSE))
The ?graph.edgelist shows other constructors for graphs. It seems that graph has what you need:
library(igraph)
edges <- data.frame(v1 = c(1, 2, 1), v2 = c(2, 3, 3))
g <- graph(edges = t(as.matrix(edges)), n = 8, directed = FALSE)
get.adjacency(g)
# 8 x 8 sparse Matrix of class "dgCMatrix"
#
# [1,] . 1 1 . . . . .
# [2,] 1 . 1 . . . . .
# [3,] 1 1 . . . . . .
# [4,] . . . . . . . .
# [5,] . . . . . . . .
# [6,] . . . . . . . .
# [7,] . . . . . . . .
# [8,] . . . . . . . .
