public void CompareSearch <TVertex, TEdge>(
[PexAssumeNotNull] IBidirectionalGraph <TVertex, TEdge> g,
TVertex root, TVertex target)
where TEdge : IEdge <TVertex>
{
Func <TEdge, double> edgeWeights = e => 1;
var distanceRelaxer = DistanceRelaxers.ShortestDistance;
var search = new BestFirstFrontierSearchAlgorithm <TVertex, TEdge>(
null,
g,
edgeWeights,
distanceRelaxer);
var recorder = new VertexDistanceRecorderObserver <TVertex, TEdge>(edgeWeights);
using (recorder.Attach(search))
search.Compute(root, target);
var dijkstra = new DijkstraShortestPathAlgorithm <TVertex, TEdge>(g, edgeWeights, distanceRelaxer);
var dijRecorder = new VertexDistanceRecorderObserver <TVertex, TEdge>(edgeWeights);
using (dijRecorder.Attach(dijkstra))
dijkstra.Compute(root);
var fvp = recorder.Distances;
var dvp = dijRecorder.Distances;
double cost;
if (dvp.TryGetValue(target, out cost))
{
Assert.IsTrue(fvp.ContainsKey(target), "target {0} not found, should be {1}", target, cost);
Assert.AreEqual(dvp[target], fvp[target]);
}
}
private static void CompareSearches <TVertex, TEdge>(
[NotNull] IBidirectionalGraph <TVertex, TEdge> graph,
[NotNull] TVertex root,
[NotNull] TVertex target)
where TEdge : IEdge <TVertex>
{
double EdgeWeights(TEdge edge) => 1.0;
IDistanceRelaxer distanceRelaxer = DistanceRelaxers.ShortestDistance;
var search = new BestFirstFrontierSearchAlgorithm <TVertex, TEdge>(
graph,
EdgeWeights,
distanceRelaxer);
var recorder = new VertexDistanceRecorderObserver <TVertex, TEdge>(EdgeWeights);
using (recorder.Attach(search))
search.Compute(root, target);
var dijkstra = new DijkstraShortestPathAlgorithm <TVertex, TEdge>(graph, EdgeWeights, distanceRelaxer);
var dijkstraRecorder = new VertexDistanceRecorderObserver <TVertex, TEdge>(EdgeWeights);
using (dijkstraRecorder.Attach(dijkstra))
dijkstra.Compute(root);
IDictionary <TVertex, double> bffsVerticesDistances = recorder.Distances;
IDictionary <TVertex, double> dijkstraVerticesDistances = dijkstraRecorder.Distances;
if (dijkstraVerticesDistances.TryGetValue(target, out double cost))
{
Assert.IsTrue(bffsVerticesDistances.ContainsKey(target), $"Target {target} not found, should be {cost}.");
Assert.AreEqual(dijkstraVerticesDistances[target], bffsVerticesDistances[target]);
}
}
public void RunSearch <TVertex, TEdge>(
[PexAssumeNotNull] IBidirectionalGraph <TVertex, TEdge> g)
where TEdge : IEdge <TVertex>
{
if (g.VertexCount == 0)
{
return;
}
Func <TEdge, double> edgeWeights = e => 1;
var distanceRelaxer = DistanceRelaxers.ShortestDistance;
var search = new BestFirstFrontierSearchAlgorithm <TVertex, TEdge>(
null,
g,
edgeWeights,
distanceRelaxer);
var root = Enumerable.First(g.Vertices);
var target = Enumerable.Last(g.Vertices);
var recorder = new VertexPredecessorRecorderObserver <TVertex, TEdge>();
using (recorder.Attach(search))
search.Compute(root, target);
if (recorder.VertexPredecessors.ContainsKey(target))
{
TestConsole.WriteLine("cost: {0}", recorder.VertexPredecessors[target]);
IEnumerable <TEdge> path;
Assert.IsTrue(recorder.TryGetPath(target, out path));
}
#if DEBUG
TestConsole.WriteLine("operator max count: {0}", search.OperatorMaxCount);
#endif
}
private static void RunSearch <TVertex, TEdge>(
[NotNull] IBidirectionalGraph <TVertex, TEdge> graph)
where TEdge : IEdge <TVertex>
{
if (graph.VertexCount == 0)
{
return;
}
IDistanceRelaxer distanceRelaxer = DistanceRelaxers.ShortestDistance;
var search = new BestFirstFrontierSearchAlgorithm <TVertex, TEdge>(
graph,
e => 1,
distanceRelaxer);
TVertex root = graph.Vertices.First();
TVertex target = graph.Vertices.Last();
var recorder = new VertexPredecessorRecorderObserver <TVertex, TEdge>();
using (recorder.Attach(search))
search.Compute(root, target);
if (recorder.VertexPredecessors.ContainsKey(target))
{
Assert.IsTrue(recorder.TryGetPath(target, out _));
}
}
public static IDictionary <string, TaggedEdge <string, string> > GetVertexPredecessor(IBidirectionalGraph <string, TaggedEdge <string, string> > g, string root, string target)
{
IDistanceRelaxer distanceRelaxer = DistanceRelaxers.EdgeShortestDistance;
var algorithm = new BestFirstFrontierSearchAlgorithm <string, TaggedEdge <string, string> >(g, edgeWeights => double.Parse(edgeWeights.Tag), distanceRelaxer);
var recorder = new VertexPredecessorRecorderObserver <string, TaggedEdge <string, string> >();
using (recorder.Attach(algorithm))
algorithm.Compute(root, target);
return(recorder.VerticesPredecessors);
}
public static IDictionary <int, Edge <int> > GetVertexPredecessor(IBidirectionalGraph <int, Edge <int> > g, int root, int target)
{
IDistanceRelaxer distanceRelaxer = DistanceRelaxers.EdgeShortestDistance;
var algorithm = new BestFirstFrontierSearchAlgorithm <int, Edge <int> >(g, edgeWeights => 1.0, distanceRelaxer);
var recorder = new VertexPredecessorRecorderObserver <int, Edge <int> >();
using (recorder.Attach(algorithm))
algorithm.Compute(root, target);
return(recorder.VerticesPredecessors);
}
public static bool FoundTarget <TVertex, TEdge>(IBidirectionalGraph <TVertex, TEdge> g, TVertex root, TVertex target) where TEdge : IEdge <TVertex>
{
IDistanceRelaxer distanceRelaxer = DistanceRelaxers.EdgeShortestDistance;
var algorithm = new BestFirstFrontierSearchAlgorithm <TVertex, TEdge>(g, edgeWeights => 1.0, distanceRelaxer);
bool targetReached = false;
algorithm.TargetReached += (sender, args) => targetReached = true;
var recorder = new VertexPredecessorRecorderObserver <TVertex, TEdge>();
using (recorder.Attach(algorithm))
algorithm.Compute(root, target);
return(targetReached);
}
static void FrontierDijkstra <TVertex, TEdge>(
IBidirectionalGraph <TVertex, TEdge> g,
Dictionary <TEdge, double> distances,
TVertex root,
TVertex target)
where TEdge : IEdge <TVertex>
{
var algo = new BestFirstFrontierSearchAlgorithm <TVertex, TEdge>(
null,
g,
AlgorithmExtensions.GetIndexer(distances),
DistanceRelaxers.ShortestDistance
);
var predecessors = new VertexPredecessorRecorderObserver <TVertex, TEdge>();
using (predecessors.Attach(algo))
algo.Compute(root, target);
}
public void SameStartAndEnd()
{
var graph = new BidirectionalGraph <int, Edge <int> >();
graph.AddVerticesAndEdge(new Edge <int>(1, 3));
graph.AddVerticesAndEdge(new Edge <int>(1, 2));
graph.AddVerticesAndEdge(new Edge <int>(2, 5));
graph.AddVerticesAndEdge(new Edge <int>(2, 4));
graph.AddVerticesAndEdge(new Edge <int>(5, 6));
graph.AddVerticesAndEdge(new Edge <int>(5, 7));
var algorithm = new BestFirstFrontierSearchAlgorithm <int, Edge <int> >(
graph, _ => 1.0, DistanceRelaxers.ShortestDistance);
bool targetReached = false;
algorithm.TargetReached += (_, _) => targetReached = true;
algorithm.Compute(1, 1);
Assert.IsTrue(targetReached);
}
private static void RunAndCheckSearch <TVertex, TEdge>(
[NotNull] IBidirectionalGraph <TVertex, TEdge> graph)
where TEdge : IEdge <TVertex>
{
if (graph.VertexCount == 0)
{
return;
}
IDistanceRelaxer distanceRelaxer = DistanceRelaxers.ShortestDistance;
var search = new BestFirstFrontierSearchAlgorithm <TVertex, TEdge>(
graph,
_ => 1.0,
distanceRelaxer);
bool targetReached = false;
search.TargetReached += (_, _) => targetReached = true;
TVertex root = graph.Vertices.First();
TVertex target = graph.Vertices.Last();
var recorder = new VertexPredecessorRecorderObserver <TVertex, TEdge>();
using (recorder.Attach(search))
search.Compute(root, target);
if (recorder.VerticesPredecessors.ContainsKey(target))
{
Assert.IsTrue(recorder.TryGetPath(target, out IEnumerable <TEdge> path));
if (Equals(root, path.First().Source))
{
Assert.IsTrue(targetReached);
}
else
{
Assert.IsFalse(targetReached);
}
}
}