How to create a bipartite network in R with igraph or tnet

Question

I have an edgelist for a two mode network, similar to this:

person  Event
Amy     football_game
Sam     picnic
Bob     art_show

I want to p

Answer 1

In igraph a bipartite network is one that has a type vertex attribute. This attribute must be logical and must the TRUE for one of the node types and FALSE for the others. So to create a bipartite network from your edge list, you simply create a regular graph and then add the type vertex attribute:

edgelist <- read.table(text="Person    Event
                         Amy       football
                         Bob       picnic
                         Sam       artshow", 
                   header=TRUE)
igraph <- graph.data.frame(edgelist)

V(igraph)$type <- V(igraph)$name %in% edgelist[,1]
igraph
# IGRAPH DN-B 6 3 -- 
# + attr: name (v/c), type (v/x)

The 'B' letter tells you that this is a bipartite graph. You can create the unipartite projections of this network via:

bipartite.projection(igraph)
# $proj1
# IGRAPH UN-B 3 0 -- 
# + attr: name (v/c), type (v/x)
#
# $proj2
# IGRAPH UN-B 3 0 -- 
# + attr: name (v/c), type (v/x)

This will return a list of two graphs. If you think that the projection might be too big, you can first call the bipartite.projection.size function, this will give you the number of vertices and edges in both projections. The memory requirement for an igraph graph is (4m+2n)*8+O(1) bytes, where 'n' is the number of vertices and 'm' is the number of edges.