Find One Total Order Consistent with Partial Order or With Directed Acyclic Graph
an atomic vector
an atomic vector of the same mode and length as
an atomic vector of the same mode as
(from[i], to[i]) can be though of either as elements of
a relation on a set or as edges in a directed graph.
This function finds one total order on the domain (nodes of the graph)
that is consistent with the relation (graph) if one exists (that is if the
graph is directed).
A vector that is a reordering of
domain so that every element of
from appears in the value before the corresponding element of
Throws an error if there is no consistent total order (the graph has a cycle).
1 2 3 4 5