# count_isomorphisms

From igraph v1.2.2
by Gabor Csardi

##### Count the number of isomorphic mappings between two graphs

Count the number of isomorphic mappings between two graphs

##### Usage

`count_isomorphisms(graph1, graph2, method = "vf2", ...)`

##### Arguments

- graph1
The first graph.

- graph2
The second graph.

- method
Currently only ‘vf2’ is supported, see

`isomorphic`

for details about it and extra arguments.- ...
Passed to the individual methods.

##### Value

Number of isomirphic mappings between the two graphs.

##### References

LP Cordella, P Foggia, C Sansone, and M Vento: An improved algorithm
for matching large graphs, *Proc. of the 3rd IAPR TC-15 Workshop
on Graphbased Representations in Pattern Recognition*, 149--159, 2001.

##### See Also

Other graph isomorphism: `count_subgraph_isomorphisms`

,
`graph_from_isomorphism_class`

,
`isomorphic`

,
`isomorphism_class`

,
`isomorphisms`

,
`subgraph_isomorphic`

,
`subgraph_isomorphisms`

##### Examples

```
# NOT RUN {
# colored graph isomorphism
g1 <- make_ring(10)
g2 <- make_ring(10)
isomorphic(g1, g2)
V(g1)$color <- rep(1:2, length = vcount(g1))
V(g2)$color <- rep(2:1, length = vcount(g2))
# consider colors by default
count_isomorphisms(g1, g2)
# ignore colors
count_isomorphisms(g1, g2, vertex.color1 = NULL,
vertex.color2 = NULL)
# }
```

*Documentation reproduced from package igraph, version 1.2.2, License: GPL (>= 2)*

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