| edges2vees {spatstat.geom} | 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 rolfturner@posteo.net
See Also
Examples
i <- c(1, 2, 5, 5, 1, 4, 2)
j <- c(2, 3, 3, 1, 3, 2, 5)
edges2vees(i, j)