# cocitation

##### Cocitation coupling

Two vertices are cocited if there is another vertex citing both of them.
`cocitation`

siply counts how many types two vertices are cocited. The
bibliographic coupling of two vertices is the number of other vertices they
both cite, `bibcoupling`

calculates this.

- Keywords
- graphs

##### Usage

`cocitation(graph, v = V(graph))`

##### Arguments

- graph
The graph object to analyze

- v
Vertex sequence or numeric vector, the vertex ids for which the cocitation or bibliographic coupling values we want to calculate. The default is all vertices.

##### Details

`cocitation`

calculates the cocitation counts for the vertices in the
`v`

argument and all vertices in the graph.

`bibcoupling`

calculates the bibliographic coupling for vertices in
`v`

and all vertices in the graph.

Calculating the cocitation or bibliographic coupling for only one vertex costs the same amount of computation as for all vertices. This might change in the future.

##### Value

A numeric matrix with `length(v)`

lines and
`vcount(graph)`

columns. Element `(i,j)`

contains the cocitation
or bibliographic coupling for vertices `v[i]`

and `j`

.

##### Examples

```
# NOT RUN {
g <- make_ring(10)
cocitation(g)
bibcoupling(g)
# }
```

*Documentation reproduced from package igraph, version 1.0.1, License: GPL (>= 2)*