% Generated by roxygen2: do not edit by hand
% Please edit documentation in R/topology.R
\name{count_isomorphisms}
\alias{count_isomorphisms}
\alias{graph.count.isomorphisms.vf2}
\title{Count the number of isomorphic mappings between two graphs}
\usage{
count_isomorphisms(graph1, graph2, method = "vf2", ...)
}
\arguments{
\item{graph1}{The first graph.}

\item{graph2}{The second graph.}

\item{method}{Currently only \sQuote{vf2} is supported, see
\code{\link[=isomorphic]{isomorphic()}} for details about it and extra arguments.}

\item{...}{Passed to the individual methods.}
}
\value{
Number of isomorphic mappings between the two graphs.
}
\description{
Count the number of isomorphic mappings between two graphs
}
\section{Related documentation in the C library}{
\href{https://igraph.org/c/html/0.10.17/igraph-Isomorphism.html#igraph_count_isomorphisms_vf2}{\code{count_isomorphisms_vf2()}}, \href{https://igraph.org/c/html/0.10.17/igraph-Basic.html#igraph_vcount}{\code{vcount()}}, \href{https://igraph.org/c/html/0.10.17/igraph-Basic.html#igraph_edges}{\code{edges()}}, \href{https://igraph.org/c/html/0.10.17/igraph-Basic.html#igraph_get_eids}{\code{get_eids()}}, \href{https://igraph.org/c/html/0.10.17/igraph-Basic.html#igraph_ecount}{\code{ecount()}}
}

\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
)
}
\references{
LP Cordella,  P Foggia, C Sansone, and M Vento: An improved algorithm
for matching large graphs, \emph{Proc. of the 3rd IAPR TC-15 Workshop
on Graphbased Representations in Pattern Recognition}, 149--159, 2001.
}
\seealso{
Other graph isomorphism: 
\code{\link{canonical_permutation}()},
\code{\link{count_subgraph_isomorphisms}()},
\code{\link{graph_from_isomorphism_class}()},
\code{\link{isomorphic}()},
\code{\link{isomorphism_class}()},
\code{\link{isomorphisms}()},
\code{\link{subgraph_isomorphic}()},
\code{\link{subgraph_isomorphisms}()}
}
\concept{graph isomorphism}
