Determines if a half-trek system exists in the mixed graph.
getHalfTrekSystem(this, fromNodes, toNodes)# S3 method for MixedGraphFixedOrder
getHalfTrekSystem(this, fromNodes, toNodes)
# S3 method for MixedGraph
getHalfTrekSystem(this, fromNodes, toNodes)
the mixed graph object
the nodes from which the half-trek system should start. If length(fromNodes) > length(toNodes) will find if there exists any half-trek system from any subset of fromNodes of size length(toNodes) to toNodes.
the nodes where the half-trek system should end.
a list with two named components, systemExists (TRUE if a
system exists, FALSE otherwise) and activeFrom (the subset
of fromNodes from which the maximal half-trek system was started).