R: List Dihedral Triples in a Graph

edges2vees {spatstat} | R Documentation

## List Dihedral Triples in a Graph

### Description

Given a list of edges between vertices, compile a list of all ‘vees’ or dihedral triples formed by these edges.

### Usage

    edges2vees(iedge, jedge, nvert=max(iedge, jedge), ...,
                    check=TRUE)

### Arguments

`iedge,jedge` | Integer vectors, of equal length, specifying the edges.
`nvert` | Number of vertices in the network.
`...` | Ignored
`check` | Logical. Whether to check validity of input data.

### Details

Given a finite graph with `nvert` vertices and with edges specified by `iedge, jedge`, this low-level function finds all ‘vees’ or ‘dihedral triples’ in the graph, that is, all triples of vertices `(i,j,k)` where `i` and `j` are joined by an edge and `i` and `k` are joined by an edge.

The interpretation of `iedge, jedge` is that each successive pair of entries specifies an edge in the graph. The kth edge joins vertex `iedge[k]` to vertex `jedge[k]`. Entries of `iedge` and `jedge` must be integers from 1 to `nvert`.

### Value

A 3-column matrix of integers, in which each row represents a triple of vertices, with the first vertex joined to the other two vertices.

### Author(s)

Adrian Baddeley Adrian.Baddeley@curtin.edu.au

and Rolf Turner r.turner@auckland.ac.nz

### See Also

`edges2triangles`

### Examples

     i <- c(1, 2, 5, 5, 1, 4, 2)
     j <- c(2, 3, 3, 1, 3, 2, 5)
     edges2vees(i, j)

[Package spatstat version 1.54-0 Index]