Port sparse SubGraph adaptor from SVN

[Alpar Juttner]

The SubGraph class in the 0.x series stores the unhidden edges/nodes as a double linked list (just as ListGraph does), therefore it provides better performance than the SubGraphAdaptor when the subgraph is sparse.

SubGraphAdaptor has been renamed to SubGraph in the 1.x series, thus I suggest to call the linked list based implementation as SparseSubGraph.

[Peter Kovacs]

Replying to alpar:

SubGraphAdaptor has been renamed to SubGraph in the 1.x series, thus I suggest to call the linked list based implementation as SparseSubGraph.

Or ListSubDigraph/ListSubGraph? It is similar to ListArcSet/ListEdgeSet, however it is maybe too similar to ListDigraph/ListGraph.

[Alpar Juttner]

Replying to kpeter:

Or ListSubDigraph/ListSubGraph? It is similar to ListArcSet/ListEdgeSet, however it is maybe too similar to ListDigraph/ListGraph.

It may be. But note, that SmartSubGraph would not be an alternative here.