R: Count the number of isomorphic mappings between two graphs

count_isomorphisms {igraph} | R Documentation

## Count the number of isomorphic mappings between two graphs

### Description

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 isomorphic 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

    # 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)

[Package igraph version 1.3.2 Index]