# triad.census

From igraph v0.5.5-3
by Gabor Csardi

##### Triad census, subgraphs with three vertices

This function counts the different subgraphs of three vertices in a graph.

- Keywords
- graphs

##### Usage

`triad.census(graph)`

##### Arguments

- graph
- The input graph, it should be directed. An undirected graph results a warning, and undefined results.

##### Details

Triad census was defined by David and Leinhardt (see References below). Every triple of vertices (A, B, C) are classified into the 16 possible states:

- 003

##### Value

- A numeric vector, the subgraph counts, in the order given in the above description.

##### concept

Triad census

##### code

##### References

See also Davis, J.A. and Leinhardt, S. (1972). The Structure of Positive Interpersonal Relations in Small Groups. In J. Berger (Ed.), Sociological Theories in Progress, Volume 2, 218-251. Boston: Houghton Mifflin.

##### See Also

`dyad.census`

for classifying binary relationships,
`graph.motifs`

for the underlying implementation.

##### Examples

```
g <- erdos.renyi.game(15, 45, type="gnm", dir=TRUE)
triad.census(g)
```

*Documentation reproduced from package igraph, version 0.5.5-3, License: GPL (>= 2)*

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