Important: The networks package has been deprecated.  Use the superseding package GraphTheory instead.

This routine is used to recover the names of the vertices at the ends of a specified edge.

In the special case where only the graph G is specified then the ends of all of the edges of G are returned as a set.

If an edge e is directed then the ends are returned as a list of length 2 where the second element is the head.  For undirected edges the vertex names are returned as a set.  Undirected loops will appear as a set containing one vertex name.

Specific edges of interest may be specified either individually or as a set or list of edge names. The result will be a vertex pair, a set of vertex pairs, or a list of vertex pairs as appropriate.

This routine is normally loaded via the command with(networks) but may also be referenced using the full name networks[ends](...).

$\mathrm{with}\left(\mathrm{networks}\right)\:$

$G≔\mathrm{cycle}\left(5\right)\:$

$\mathrm{Eset}≔\left\{\mathrm{addedge}\left(\left\{\left[1\,3\right]\,\left[2\,2\right]\right\}\,G\right)\right\}$

$\mathrm{Eset}≔\left\{\mathrm{e6}\,\mathrm{e7}\right\}$

$\mathrm{ends}\left(\mathrm{Eset}\,G\right)$

$\left\{\left[1\,3\right]\,\left[2\,2\right]\right\}$

$\mathrm{ends}\left(\mathrm{convert}\left(\mathrm{Eset}\,\mathrm{list}\right)\,G\right)$

$\left[\left[1\,3\right]\,\left[2\,2\right]\right]$

$\mathrm{ends}\left(G\right)$

$\left\{\left[1\,3\right]\,\left[2\,2\right]\,\left\{1\,2\right\}\,\left\{1\,5\right\}\,\left\{2\,3\right\}\,\left\{3\,4\right\}\,\left\{4\,5\right\}\right\}$