R: Connectivity components of an undirected graph

con.comp {prabclus} | R Documentation

## Connectivity components of an undirected graph

### Description

Computes the connectivity components of an undirected graph from a matrix giving the edges.

### Usage

    con.comp(comat)

### Arguments

`comat` | a symmetric logical or 0-1 matrix, where `comat[i,j]=TRUE` means that there is an edge between vertices `i` and `j`. The diagonal is ignored.

### Details

The "depth-first search" algorithm of Cormen, Leiserson and Rivest (1990, p. 477) is used.

### Value

An integer vector, giving the number of the connectivity component for each vertice.

### Author(s)

Christian Hennig chrish@stats.ucl.ac.uk http://www.homepages.ucl.ac.uk/~ucakche

### References

Cormen, T. H., Leiserson, C. E. and Rivest, R. L. (1990), Introduction to Algorithms, Cambridge: MIT Press.

### See Also

`hclust`, `cutree` for cutted single linkage trees (often equivalent).

### Examples

      set.seed(1000)
      x <- rnorm(20)
      m <- matrix(0,nrow=20,ncol=20)
      for(i in 1:20)
        for(j in 1:20)
          m[i,j] <- abs(x[i]-x[j])
      d <- m<0.2
      cc <- con.comp(d)
      max(cc) # number of connectivity components
      plot(x,cc)
      # The same should be produced by
      # cutree(hclust(as.dist(m),method="single"),h=0.2).

[Package prabclus version 2.2-6 Index]