# get.incidence

0th

Percentile

##### Incidence matrix of a bipartite graph

This function can return a sparse of dense incidence matrix of a bipartite network. The incidence matrix is an n times m matrix, n and m are the number of vertices of the two kinds.x

Keywords
graphs
##### Usage
get.incidence(graph, types=NULL, attr=NULL, names=TRUE, sparse=FALSE)
##### Arguments
graph
The input graph. The direction of the edges is ignored in directed graphs.
types
An optional vertex type vector to use instead of the type vertex attribute. You must supply this argument if the graph has no type vertex attribute.
attr
Either NULL or a character string giving an edge attribute name. If NULL a traditional incidence matrix is returned. If not NULL then the values of the given edge attribute are included in the incidence m
names
Logical scalar, if TRUE and the vertices in the graph are named (i.e. the graph has a vertex attribute called name), then vertex names will be added to the result as row and column names. Otherwise th
sparse
Logical scalar, if it is TRUE then a sparse matrix is created, you will need the Matrix package for this.
##### Details

Bipartite graphs have a type vertex attribute in igraph, this is boolean and FALSE for the vertices of the first kind and TRUE for vertices of the second kind.

The vertex ids corresponding to rows and columns in the incidence matrix are returned as row/column names.

##### Value

• A sparse or dense matrix.

##### concept

• Bipartite graph
• Two-mode network
• Incidence matrix

graph.incidence for the opposite operation.
g <- graph.bipartite( c(0,1,0,1,0,0), c(0,1,1,2,2,3) )
get.incidence(g)