DirectionTransformer
: generates graphs where input undirected
edges have been converted to directed edges, or vice versa
FoldingTransformer
: transforms k-partite graphs or hypergraphs
into unipartite graphs
VertexPartitionCollapser
: transforms a graph, given a
partition of its vertices into disjoint sets, into a graph in which each
of these disjoint sets has been 'collapsed' into a single new vertex.