public static void MergeVertices <TVertex, TEdge>(this IMutableBidirectionalGraph <TVertex, TEdge> graph,
IEnumerable <TVertex> verticesToMerge,
TVertex replacement,
Func <TEdge, TVertex, TEdge> mergeInFunc,
Func <TVertex, TEdge, TEdge> mergeOutFunc,
IEqualityComparer <TVertex> comparer = null,
bool checkExistence = false)
where TEdge : IEdge <TVertex>
{
var verticies = (checkExistence ? graph.Vertices.Intersect(verticesToMerge, comparer) : verticesToMerge).ToList();
var allInEdges = verticies.SelectMany(graph.InEdges);
var allOutEdges = verticies.SelectMany(graph.OutEdges);
var newInEdges = allInEdges.Select(x => mergeInFunc(x, replacement));
var newOutEdges = allOutEdges.Select(x => mergeOutFunc(replacement, x));
verticies.ForEach(x => graph.RemoveVertex(x));
graph.AddVertex(replacement);
graph.AddEdgeRange(newInEdges);
graph.AddEdgeRange(newOutEdges);
}
public static void DeleteVerticesAndMergeEdges <TVertex, TEdge>
(this IMutableBidirectionalGraph <TVertex, TEdge> graph, TVertex vertexToDelete,
Func <TEdge, TEdge, TEdge> mergeFunc)
where TEdge : IEdge <TVertex>
{
if (graph.IsInEdgesEmpty(vertexToDelete) || graph.IsOutEdgesEmpty(vertexToDelete))
{
//simple case
graph.RemoveVertex(vertexToDelete);
}
else
{
//need to keep connections
var newEdges = from e1 in graph.InEdges(vertexToDelete)
from e2 in graph.OutEdges(vertexToDelete)
select mergeFunc(e1, e2);
//create edges
var newEdgesList = newEdges.ToList();
graph.AddEdgeRange(newEdgesList);
graph.RemoveVertex(vertexToDelete);
}
}