What's the difference between a SparseMultigraph<V, E> and a SparseGraph<V, E>?

Question

I'm using JUNG2 library and they have 2 similar Graphs which are:

• SparseMultigraph
• SparseGraph

Can someone tell me the differences between them?

Thanks.

Answer 1

I think SparseGraph<V, E> does not support parallel edges.

while SparseMultigraph<V, E> allows parallel edges.

Multigraph: https://en.wikipedia.org/wiki/Multigraph

Answer 2

The name of the class(es) almost tell it.

• SparseMultigraph is a multigraph, which means that there might be multiple (>= 1) or zero edges between two vertices. The SparseMultigraph class implements the Multigraph interface.

• SparseGraph is a graph, which means that there is exactly 0 or exactly 1 edge between any two vertices. The SparseGraph class doesn't not implement the Multigraph interface, but only the Graph interface.

• Both classes extend the AbstractGraph class.

More info:

• What is a Multigraph?