QuickGraph Dijkstra example

Question

I have an AdjacencyGraph<string, Edge<string>> which I would like to run AlgorithmExtensions.ShortestPathsDijkstra on, but the QuickGraph documentation isn't the best.

Does anyone have an example I can follow?

Everything I found on Google used an observer, which the AlgorithmExtension doesn't require.

Answer 1

I've updated the docs but in a nutshell, you need a graph, a edge weight map (as a delegate) and a root vertex. The AlgorithmExtensions method returns a 'TryFunc' that you can query to fetch shortest paths.

using QuickGraph;
using QuickGraph.Algorithms;

IVertexAndEdgeListGraph<TVertex, TEdge> graph = ...;
Func<TEdge, double> edgeCost = e => 1; // constant cost
TVertex root = ...;

// compute shortest paths
TryFunc<TVertex, TEdge> tryGetPaths = graph.ShortestPathDijkstra(edgeCost, root);

// query path for given vertices
TVertex target = ...;
IEnumerable<TEdge> path;
if (tryGetPaths(target, out path))
    foreach(var edge in path)
        Console.WriteLine(edge);