public void FindDisconnectedSubGraphsTest()
{
SimpleGraph <string, Edge <string> > graph = new SimpleGraph <string, Edge <string> >(false);
graph.Add(new Edge <string>("A", "B", false)); // A->B
graph.Add(new Edge <string>("A", "C", false)); // A->C
graph.Add(new Edge <string>("B", "D", false)); // B->D
graph.Add(new Edge <string>("C", "D", false)); // C->D
graph.Add(new Edge <string>("D", "E", false)); // D->E
graph.Add(new Edge <string>("G", "F", false)); // G->F, different subgraph
Assert.IsFalse(graph.IsConnected());
DisconnectedGraphsFinder <string, Edge <string> > finder = new DisconnectedGraphsFinder <string, Edge <string> >(
() => new SubGraphView <string, Edge <string> >(graph), graph);
finder.FindDisconnectedGraphs();
Assert.AreEqual(2, finder.FoundDisconnectedGraphs.Count);
Assert.AreEqual(5, finder.FoundDisconnectedGraphs[0].Vertices.Count());
Assert.AreEqual(2, finder.FoundDisconnectedGraphs[1].Vertices.Count());
Assert.AreEqual(5, finder.FoundDisconnectedGraphs[0].Edges.Count());
Assert.AreEqual(1, finder.FoundDisconnectedGraphs[1].Edges.Count());
finder.FindDisconnectedGraphs("A", true);
Assert.AreEqual(1, finder.FoundDisconnectedGraphs.Count);
Assert.AreEqual(5, finder.FoundDisconnectedGraphs[0].Vertices.Count());
Assert.AreEqual(5, finder.FoundDisconnectedGraphs[0].Edges.Count());
}
/*public static IEnumerable<IMutableVertexAndEdgeListGraph<TVertex, TEdge>> StronglyConnectedComponents<TVertex, TEdge>(this IVertexListGraph<TVertex, TEdge> g, Func<IMutableVertexAndEdgeListGraph<TVertex, TEdge>> componentMaker)
* where TEdge : QuickGraph.IEdge<TVertex>
* {
* g.StronglyConnectedComponents(out var scc);
*
* return scc.GroupBy(kv => kv.Value).Select(group =>
* {
* var c = componentMaker();
*
* group.ForEach(kv => c.AddVertex(kv.Key));
*
* foreach (var v1 in c.Vertices)
* foreach (var v2 in c.Vertices)
* {
* if (g.TryGetEdges(v1, v2, out var edges))
* edges.ForEach(e => c.AddEdge(e));
* }
* });
* }*/
/// <summary>
/// Returns the list of weakly connected components in a graph. A weakly connected component is one in which
/// <list type="number">
/// <item>for every pair of vertices V,W, W is reachable from V, ignoring edge-direction, and </item>
/// <item>one cannot add another node U such that the first property still holds.</item>
/// </list>
/// </summary>
/// <typeparam name="TGraph">The type of the produced components.</typeparam>
/// <typeparam name="TVertex">The type of the vertices.</typeparam>
/// <typeparam name="TEdge">The type of the edges.</typeparam>
/// <param name="g">The graph.</param>
/// <param name="componentMaker">A producer-function for empty empty components.</param>
public static IList <TGraph> WeaklyConnectedComponents <TGraph, TVertex, TEdge>(this GraphBase <TVertex, TEdge> g, Func <TGraph> componentMaker)
where TEdge : class, IEdge <TVertex>
where TGraph : GraphBase <TVertex, TEdge>
{
var undirected = new NonDirectedGraph <TVertex, NonDirectedEdge <TVertex> >();
g.Vertices.ForEach(undirected.Add);
g.Edges.ForEach(e => undirected.Add(new NonDirectedEdge <TVertex>(e.StartVertex, e.EndVertex)));
var subgraphs = new List <TGraph>();
//Find the subgraphs (connected components that are candidates for being turned into trees).
var dcGraphFinder = new DisconnectedGraphsFinder <TVertex, NonDirectedEdge <TVertex> >(
() => new SubGraphView <TVertex, NonDirectedEdge <TVertex> >(undirected), undirected);
dcGraphFinder.FindDisconnectedGraphs();
foreach (var component in dcGraphFinder.FoundDisconnectedGraphs)
{
var subG = componentMaker();
component.Vertices.ForEach(subG.Add);
foreach (var v1 in component.Vertices)
{
foreach (var v2 in component.Vertices)
{
g.GetEdges(v1, v2).ForEach(subG.Add);
}
}
subgraphs.Add(subG);
}
return(subgraphs);
}
