# as_incidence_matrix

From igraph v1.0.0
by Gabor Csardi

##### Incidence matrix of a bipartite graph

This function can return a sparse or 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.

- Keywords
- graphs

##### Usage

```
as_incidence_matrix(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`

, then a traditional incidence matrix is returned. If not`NULL`

then the values of the given edge attribute are included in the incidence matrix. - 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 the ids of the vertices are use - 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.

##### Value

- A sparse or dense matrix.

##### See Also

`graph_from_incidence_matrix`

for the opposite operation.

##### Examples

```
g <- make_bipartite_graph( c(0,1,0,1,0,0), c(1,2,2,3,3,4) )
as_incidence_matrix(g)
```

*Documentation reproduced from package igraph, version 1.0.0, License: GPL (>= 2)*

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