/// <summary>
/// Calculates a path.
/// </summary>
/// <returns>The path.</returns>
public Path Run(RouterDb routerDb, SnapPoint source, SnapPoint target,
Func <RouterDbEdgeEnumerator, uint> getWeight, Func <VertexId, bool> settled = null, Func <VertexId, bool> queued = null)
{
var enumerator = routerDb.GetEdgeEnumerator();
_tree.Clear();
_visits.Clear();
_heap.Clear();
// add sources.
// add forward.
if (!enumerator.MoveToEdge(source.EdgeId, true))
{
throw new Exception($"Edge in source {source} not found!");
}
var sourceCostForward = getWeight(enumerator);
if (sourceCostForward > 0)
{
// can traverse edge in the forward direction.
var sourceOffsetCostForward = sourceCostForward * (1 - source.OffsetFactor());
var p = _tree.AddVisit(enumerator.To, source.EdgeId, uint.MaxValue);
_heap.Push(p, sourceOffsetCostForward);
}
// add backward.
if (!enumerator.MoveToEdge(source.EdgeId, false))
{
throw new Exception($"Edge in source {source} not found!");
}
var sourceCostBackward = getWeight(enumerator);
if (sourceCostBackward > 0)
{
// can traverse edge in the backward direction.
var sourceOffsetCostBackward = sourceCostBackward * source.OffsetFactor();
var p = _tree.AddVisit(enumerator.To, source.EdgeId, uint.MaxValue);
_heap.Push(p, sourceOffsetCostBackward);
}
// add targets.
(uint pointer, float cost, bool forward, SnapPoint target)bestTarget = (uint.MaxValue, float.MaxValue,
false,
public void Run(DirectedGraph graph, DirectedGraph witnessGraph, uint vertex, HashSet <uint> dirty)
{
try
{
forwardSettled.Clear();
backwardSettled.Clear();
pathTree.Clear();
pointerHeap.Clear();
witnesses.Clear();
var p = pathTree.AddSettledVertex(vertex, new WeightAndDir <float>()
{
Direction = new Dir(true, true),
Weight = 0
}, 0, Constants.NO_VERTEX);
pointerHeap.Push(p, 0);
// dequeue vertices until stopping conditions are reached.
var enumerator = graph.GetEdgeEnumerator();
// calculate max forward/backward weight.
var forwardMax = 0f;
var backwardMax = 0f;
enumerator.MoveTo(vertex);
var nextEnumerator = graph.GetEdgeEnumerator();
while (enumerator.MoveNext())
{
var nVertex1 = enumerator.Neighbour;
if (dirty != null &&
!dirty.Contains(nVertex1))
{ // this is not a hop-2 to consider.
continue;
}
ContractedEdgeDataSerializer.Deserialize(enumerator.Data0,
out Dir dir1, out float weight1);
var p1 = pathTree.AddSettledVertex(nVertex1, weight1, dir1, 1, vertex);
pointerHeap.Push(p1, weight1);
nextEnumerator.MoveTo(enumerator.Neighbour);
while (nextEnumerator.MoveNext())
{
var nVertex2 = nextEnumerator.Neighbour;
if (nVertex2 == vertex)
{ // no u-turns.
continue;
}
ContractedEdgeDataSerializer.Deserialize(nextEnumerator.Data0,
out Dir dir2, out float weight2);
dir2._val = (byte)(dir1._val & dir2._val);
if (dir2._val == 0)
{
continue;
}
var weight2Hops = weight1 + weight2;
var p2 = pathTree.AddSettledVertex(nVertex2, weight2Hops, dir2, 2, nVertex1);
pointerHeap.Push(p2, weight2Hops);
if (dir2.F && weight2Hops > forwardMax)
{
forwardMax = weight2Hops;
}
if (dir2.B && weight2Hops > backwardMax)
{
backwardMax = weight2Hops;
}
}
}
if (forwardMax == 0 &&
backwardMax == 0)
{
return;
}
while (pointerHeap.Count > 0)
{
var cPointer = pointerHeap.Pop();
pathTree.GetSettledVertex(cPointer, out uint cVertex, out WeightAndDir <float> cWeight,
out uint cHops, out uint pVertex);
if (cHops == 2)
{ // check if the search can stop or not.
var witness = new Shortcut <float>();
witness.Forward = float.MaxValue;
witness.Backward = float.MaxValue;
if (cWeight.Direction.F &&
forwardSettled.TryGetValue(cVertex, out float best) &&
best < cWeight.Weight)
{ // this is a 2-hop and vertex was settled before, we have a witness!
witness.Forward = best;
}
if (cWeight.Direction.B &&
backwardSettled.TryGetValue(cVertex, out best) &&
best < cWeight.Weight)
{ // this is a 2-hop and vertex was settled before, we have a witness!
witness.Backward = best;
}
if (witness.Backward != float.MaxValue ||
witness.Forward != float.MaxValue)
{ // report witness here.
if (vertex != cVertex)
{ // TODO: check this, how can they ever be the same?
witnesses.Add(new Witness()
{
Vertex1 = vertex,
Vertex2 = cVertex,
Forward = witness.Forward,
Backward = witness.Backward
});
}
}
}
if (forwardSettled.Count > _maxSettles ||
backwardSettled.Count > _maxSettles)
{ // over settled count.
break;
}
if (cWeight.Weight > backwardMax &&
cWeight.Weight > forwardMax)
{ // over max weights.
break;
}
if (forwardSettled.ContainsKey(cVertex) ||
cWeight.Weight > forwardMax)
{
cWeight.Direction = new Dir(false, cWeight.Direction.B);
}
if (backwardSettled.ContainsKey(cVertex) ||
cWeight.Weight > backwardMax)
{
cWeight.Direction = new Dir(cWeight.Direction.F, false);
}
var isRelevant = false;
if (cWeight.Direction.F)
{
forwardSettled.Add(cVertex, cWeight.Weight);
isRelevant = true;
}
if (cWeight.Direction.B)
{
backwardSettled.Add(cVertex, cWeight.Weight);
isRelevant = true;
}
if (!isRelevant)
{ // not forward, not backwards.
continue;
}
cHops++;
if (cHops >= _hopLimit)
{ // over hop limit, don't queue.
continue;
}
if (cHops == 1)
{
if (dirty == null)
{ // all hops 1 are already queued.
continue;
}
}
else if (cHops == 2)
{
if (dirty == null ||
dirty.Contains(cVertex))
{ // all these hops 2 are already queue.
continue;
}
}
enumerator.MoveTo(cVertex);
while (enumerator.MoveNext())
{
var nVertex = enumerator.Neighbour;
if (nVertex == pVertex)
{ // no going back.
continue;
}
if (cHops == 1)
{ // check if the neighbour is dirty.
if (dirty.Contains(nVertex))
{ // skip dirty vertices, they are already in the queue.
continue;
}
}
Dir nDir;
float nWeight;
ContractedEdgeDataSerializer.Deserialize(enumerator.Data0,
out nDir, out nWeight);
nDir._val = (byte)(cWeight.Direction._val & nDir._val);
if (nDir._val == 0)
{
continue;
}
nWeight = nWeight + cWeight.Weight;
if (nDir.F && nWeight > forwardMax)
{
nDir = new Dir(false, nDir.B);
if (nDir._val == 0)
{
continue;
}
}
if (nDir.B && nWeight > backwardMax)
{
nDir = new Dir(nDir.F, false);
if (nDir._val == 0)
{
continue;
}
}
var nPoiner = pathTree.AddSettledVertex(nVertex, nWeight, nDir, cHops, cVertex);
pointerHeap.Push(nPoiner, nWeight);
}
}
if (witnesses.Count > 0)
{
lock (witnessGraph)
{
foreach (var witness in witnesses)
{
//witnessGraph.AddOrUpdateEdge(witness.Item1, witness.Item2, witness.Item3.Forward,
// witness.Item3.Backward);
witnessGraph.AddOrUpdateEdge(witness.Vertex1, witness.Vertex2,
witness.Forward, witness.Backward);
}
}
}
}
catch (Exception ex)
{
throw ex;
}
}
/// <summary>
/// Calculates witness paths.
/// </summary>
public virtual void Calculate(DirectedGraph graph, WeightHandler <T> weightHandler, uint vertex,
uint source, Dictionary <uint, Shortcut <T> > targets, int maxSettles, int hopLimit)
{
pathTree.Clear();
pointerHeap.Clear();
var forwardSettled = new HashSet <uint>();
var backwardSettled = new HashSet <uint>();
var forwardTargets = new HashSet <uint>();
var backwardTargets = new HashSet <uint>();
var maxWeight = 0f;
foreach (var targetPair in targets)
{
var target = targetPair.Key;
var shortcut = targetPair.Value;
var e = new OriginalEdge(source, target);
var shortcutForward = weightHandler.GetMetric(shortcut.Forward);
if (shortcutForward > 0 && shortcutForward < float.MaxValue)
{
forwardTargets.Add(e.Vertex2);
if (shortcutForward > maxWeight)
{
maxWeight = shortcutForward;
}
}
var shortcutBackward = weightHandler.GetMetric(shortcut.Backward);
if (shortcutBackward > 0 && shortcutBackward < float.MaxValue)
{
backwardTargets.Add(e.Vertex2);
if (shortcutBackward > maxWeight)
{
maxWeight = shortcutBackward;
}
}
}
// queue the source.
pathTree.Clear();
pointerHeap.Clear();
var p = pathTree.AddSettledVertex(source, new WeightAndDir <float>()
{
Direction = new Dir(true, true),
Weight = 0
}, 0);
pointerHeap.Push(p, 0);
// dequeue vertices until stopping conditions are reached.
var cVertex = Constants.NO_VERTEX;
WeightAndDir <float> cWeight;
var cHops = uint.MaxValue;
var enumerator = graph.GetEdgeEnumerator();
while (pointerHeap.Count > 0)
{
var cPointer = pointerHeap.Pop();
pathTree.GetSettledVertex(cPointer, out cVertex, out cWeight, out cHops);
if (cVertex == vertex)
{
continue;
}
if (cWeight.Weight >= maxWeight)
{
break;
}
if (forwardSettled.Contains(cVertex) ||
forwardTargets.Count == 0 ||
forwardSettled.Count > maxSettles)
{
cWeight.Direction = new Dir(false, cWeight.Direction.B);
}
if (backwardSettled.Contains(cVertex) ||
backwardTargets.Count == 0 ||
backwardSettled.Count > maxSettles)
{
cWeight.Direction = new Dir(cWeight.Direction.F, false);
}
if (cWeight.Direction.F)
{
forwardSettled.Add(cVertex);
if (forwardTargets.Contains(cVertex))
{ // target reached, evaluate it as a shortcut.
Shortcut <T> shortcut;
if (targets.TryGetValue(cVertex, out shortcut))
{
var shortcutForward = weightHandler.GetMetric(shortcut.Forward);
if (shortcutForward > cWeight.Weight)
{ // a witness path was found, don't add a shortcut.
shortcut.Forward = weightHandler.Zero;
targets[cVertex] = shortcut;
}
}
forwardTargets.Remove(cVertex);
if (forwardTargets.Count == 0)
{
if (backwardTargets.Count == 0)
{
break;
}
cWeight.Direction = new Dir(false, cWeight.Direction.B);
if (!cWeight.Direction.F && !cWeight.Direction.B)
{
continue;
}
}
}
}
if (cWeight.Direction.B)
{
backwardSettled.Add(cVertex);
if (backwardTargets.Contains(cVertex))
{ // target reached, evaluate it as a shortcut.
Shortcut <T> shortcut;
if (targets.TryGetValue(cVertex, out shortcut))
{
var shortcutBackward = weightHandler.GetMetric(shortcut.Backward);
if (shortcutBackward > cWeight.Weight)
{ // a witness path was found, don't add a shortcut.
shortcut.Backward = weightHandler.Zero;
targets[cVertex] = shortcut;
}
}
backwardTargets.Remove(cVertex);
if (backwardTargets.Count == 0)
{
if (forwardTargets.Count == 0)
{
break;
}
cWeight.Direction = new Dir(cWeight.Direction.F, false);
if (!cWeight.Direction.F && !cWeight.Direction.B)
{
continue;
}
}
}
}
if (cHops + 1 >= hopLimit)
{
continue;
}
if (forwardSettled.Count > maxSettles &&
backwardSettled.Count > maxSettles)
{
continue;
}
enumerator.MoveTo(cVertex);
while (enumerator.MoveNext())
{
var nVertex = enumerator.Neighbour;
var nWeight = ContractedEdgeDataSerializer.Deserialize(enumerator.Data0);
nWeight = new WeightAndDir <float>()
{
Direction = Dir.Combine(cWeight.Direction, nWeight.Direction),
Weight = cWeight.Weight + nWeight.Weight
};
if (nWeight.Direction.F &&
forwardSettled.Contains(nVertex))
{
nWeight.Direction = new Dir(false, nWeight.Direction.B);
}
if (nWeight.Direction.B &&
backwardSettled.Contains(nVertex))
{
nWeight.Direction = new Dir(nWeight.Direction.F, false);
}
if (!nWeight.Direction.F && !nWeight.Direction.B)
{
continue;
}
var nPoiner = pathTree.AddSettledVertex(nVertex, nWeight, cHops + 1);
pointerHeap.Push(nPoiner, nWeight.Weight);
}
}
}
/// <summary>
/// Finds loops and merges them together.
/// </summary>
/// <param name="maxSettles">The maximum labels to settle.</param>
/// <param name="updateLabel">A callback to update label.</param>
internal void FindLoops(uint maxSettles, IslandLabels islandLabels, Action <uint, uint> updateLabel)
{
// TODO: it's probably better to call reduce here when too much has changed.
var pathTree = new PathTree();
var enumerator = _graph.GetEdgeEnumerator();
var settled = new HashSet <uint>();
var queue = new Queue <uint>();
var loop = new HashSet <uint>(); // keeps all with a path back to label, initially only label.
uint label = 0;
while (label < _graph.VertexCount)
{
if (!enumerator.MoveTo(label))
{
label++;
continue;
}
if (islandLabels[label] != label)
{
label++;
continue;
}
queue.Clear();
pathTree.Clear();
settled.Clear();
loop.Add(label);
queue.Enqueue(pathTree.Add(label, uint.MaxValue));
while (queue.Count > 0 &&
settled.Count < maxSettles)
{
var pointer = queue.Dequeue();
pathTree.Get(pointer, out var current, out var previous);
if (settled.Contains(current))
{
continue;
}
settled.Add(current);
if (!enumerator.MoveTo(current))
{
continue;
}
while (enumerator.MoveNext())
{
var n = enumerator.Neighbour;
n = islandLabels[n];
if (loop.Contains(n))
{
// yay, a loop!
loop.Add(current);
while (previous != uint.MaxValue)
{
pathTree.Get(previous, out current, out previous);
loop.Add(current);
}
}
if (settled.Contains(n))
{
continue;
}
queue.Enqueue(pathTree.Add(n, pointer));
}
}
if (loop.Count > 0)
{
this.Merge(loop, updateLabel);
}
loop.Clear();
// move to the next label.
label++;
}
}
