/// <summary>
/// Creates a new instance of search algorithm.
/// </summary>
public BidirectionalDykstra(Dykstra <T> sourceSearch, Dykstra <T> targetSearch, WeightHandler <T> weightHandler)
{
_sourceSearch = sourceSearch;
_targetSearch = targetSearch;
_weightHandler = weightHandler;
}
/// <summary>
/// Executes the actual run of the algorithm.
/// </summary>
protected override void DoRun(CancellationToken cancellationToken)
{
_best = new EdgePath <T> [_targets.Count];
// register the targets and determine one-edge-paths.
var sourcePaths = _source.ToEdgePaths(_routerDb, _weightHandler, true);
var targetIndexesPerVertex = new Dictionary <uint, LinkedTarget>();
var targetPaths = new IEnumerable <EdgePath <T> > [_targets.Count];
for (var i = 0; i < _targets.Count; i++)
{
var targets = _targets[i].ToEdgePaths(_routerDb, _weightHandler, false);
targetPaths[i] = targets;
// determine one-edge-paths.
if (_source.EdgeId == _targets[i].EdgeId)
{ // on same edge.
_best[i] = _source.EdgePathTo(_routerDb, _weightHandler, _targets[i]);
}
// register targets.
for (var t = 0; t < targets.Length; t++)
{
var target = targetIndexesPerVertex.TryGetValueOrDefault(targets[t].Vertex);
targetIndexesPerVertex[targets[t].Vertex] = new LinkedTarget()
{
Target = i,
Next = target
};
}
}
// determine the best max search radius.
var max = _weightHandler.Zero;
for (var s = 0; s < _best.Length; s++)
{
if (_best[s] == null)
{
max = _maxSearch;
}
else
{
if (_weightHandler.IsLargerThan(_best[s].Weight, max))
{
max = _best[s].Weight;
}
}
}
// run the search.
var dykstra = new Dykstra <T>(_routerDb.Network.GeometricGraph.Graph, null, _weightHandler,
sourcePaths, max, false);
dykstra.WasFound += (vertex, weight) =>
{
LinkedTarget target;
if (targetIndexesPerVertex.TryGetValue(vertex, out target))
{ // there is a target for this vertex.
while (target != null)
{
var best = _best[target.Target];
foreach (var targetPath in targetPaths[target.Target])
{
EdgePath <T> path;
dykstra.TryGetVisit(vertex, out path);
if (targetPath.Vertex == vertex)
{ // there is a path here.
var total = _weightHandler.Add(targetPath.Weight, weight);
if (best == null ||
_weightHandler.IsSmallerThan(total, best.Weight))
{ // not a best path yet, just add this one.
if (_targets[target.Target].IsVertex(_routerDb, path.Vertex))
{ // target is the exact vertex.
best = path;
}
else
{ // target is not the exact vertex.
best = new EdgePath <T>(_targets[target.Target].VertexId(_routerDb),
total, path);
}
}
break;
}
}
// set again.
_best[target.Target] = best;
// move to next target.
target = target.Next;
}
}
return(false);
};
dykstra.Run(cancellationToken);
this.HasSucceeded = true;
}
