output = one of default or permutation

When output=permutation, returns a list of integers representing the permutation to Vertices(G) to obtain the topological order. When output=default, a list of the actual vertices is returned.

The TopologicSort command returns a linear ordering of vertices of an acyclic digraph that is consistent with the arcs of the digraph.  This means a vertex u precedes a vertex v if there is an arc from u to v. The output is a list.

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

$\mathrm{DG}≔\mathrm{Digraph}\left(\left\{\left[a\,b\right]\,\left[a\,d\right]\,\left[b\,d\right]\,\left[c\,a\right]\,\left[c\,b\right]\,\left[c\,d\right]\right\}\right)\:$

$\mathrm{IsAcyclic}\left(\mathrm{DG}\right)$

$\mathrm{true}$

$\mathrm{TopologicSort}\left(\mathrm{DG}\right)$

$\left[c\,a\,b\,d\right]$

The GraphTheory[TopologicSort] command was updated in Maple 2021.

The output option was introduced in Maple 2021.

For more information on Maple 2021 changes, see Updates in Maple 2021.