/// <summary>
/// Gets sequence 2, the last vertices right before the end vertex with a maximum of n.
/// </summary>
public static uint[] GetSequence2 <T>(this EdgePath <T> path, DirectedDynamicGraph.EdgeEnumerator enumerator, int n)
where T : struct
{
if (path.From == null)
{
return(Constants.EMPTY_SEQUENCE);
}
return(path.GetSequence2 <T>(enumerator, n, new List <uint>()));
}
public void TestGetSequence2()
{
// build graph.
var graph = new DirectedDynamicGraph(ContractedEdgeDataSerializer.DynamicFixedSize);
var e1 = graph.AddEdge(0, 1, 100, null);
var e2 = graph.AddEdge(1, 2, 100, null);
var e3 = graph.AddEdge(2, 6, 100, null, 4, new uint[] { 3 }, new uint[] { 5 });
var e4 = graph.AddEdge(6, 16, 100, null, 11, new uint[] { 7, 8, 9, 10 }, new uint[] { 12, 13, 14, 15 });
var enumerator = graph.GetEdgeEnumerator();
// build and test getting sequences from paths.
var path = new EdgePath <float>(0);
var s = path.GetSequence2(enumerator);
Assert.IsNotNull(s);
Assert.AreEqual(0, s.Length);
path = new EdgePath <float>(1, 100, new EdgePath <float>(0));
s = path.GetSequence2(enumerator);
Assert.IsNotNull(s);
Assert.AreEqual(1, s.Length);
Assert.AreEqual(0, s[0]);
path = new EdgePath <float>(2, 200, e2 + 1, new EdgePath <float>(1, 100, new EdgePath <float>(0)));
s = path.GetSequence2(enumerator);
Assert.IsNotNull(s);
Assert.AreEqual(2, s.Length);
Assert.AreEqual(0, s[0]);
Assert.AreEqual(1, s[1]);
path = new EdgePath <float>(6, 300, e3 + 1, new EdgePath <float>(2, 200, e2 + 1, new EdgePath <float>(1, 100, new EdgePath <float>(0))));
s = path.GetSequence2(enumerator);
Assert.IsNotNull(s);
Assert.AreEqual(1, s.Length);
Assert.AreEqual(5, s[0]);
path = new EdgePath <float>(16, 400, e4 + 1, new EdgePath <float>(6, 300, e3 + 1, new EdgePath <float>(2, 200, e2 + 1, new EdgePath <float>(1, 100, new EdgePath <float>(0)))));
s = path.GetSequence2(enumerator);
Assert.IsNotNull(s);
Assert.AreEqual(4, s.Length);
Assert.AreEqual(12, s[0]);
Assert.AreEqual(13, s[1]);
Assert.AreEqual(14, s[2]);
Assert.AreEqual(15, s[3]);
}
/// <summary>
/// Gets sequence 2, the last vertices right before the end vertex.
/// </summary>
public static uint[] GetSequence2 <T>(this EdgePath <T> path, DirectedDynamicGraph.EdgeEnumerator enumerator)
where T : struct
{
return(path.GetSequence2(enumerator, int.MaxValue));
}
/// <summary>
/// Executes one step in the search.
/// </summary>
public bool Step()
{
if (_heap.Count == 0)
{
return(false);
}
_current = _heap.Pop();
while (_current != null)
{ // keep trying.
LinkedEdgePath <T> edgePath = null;
if (!_visits.TryGetValue(_current.Vertex, out edgePath))
{ // this vertex has not been visited before.
_visits.Add(_current.Vertex, new LinkedEdgePath <T>()
{
Path = _current
});
break;
}
else
{ // vertex has been visited before, check if edge has.
if (!edgePath.HasPath(_current))
{ // current edge has not been used to get to this vertex.
_visits[_current.Vertex] = new LinkedEdgePath <T>()
{
Path = _current,
Next = edgePath
};
break;
}
}
_current = _heap.Pop();
}
if (_current == null)
{
return(false);
}
if (this.WasFound != null)
{
this.WasFound(_current.Vertex, _current.Weight);
}
// get relevant restrictions.
var restrictions = _getRestrictions(_current.Vertex);
// get the edge enumerator.
var currentSequence = _current.GetSequence2(_edgeEnumerator);
currentSequence = currentSequence.Append(_current.Vertex);
// get neighbours.
_edgeEnumerator.MoveTo(_current.Vertex);
// add the neighbours to the queue.
while (_edgeEnumerator.MoveNext())
{
bool?neighbourDirection;
var neighbourWeight = _weightHandler.GetEdgeWeight(_edgeEnumerator.Current, out neighbourDirection);
if (neighbourDirection == null || (neighbourDirection.Value != _backward))
{ // the edge is forward, and is to higher or was not contracted at all.
var neighbourNeighbour = _edgeEnumerator.Neighbour;
var neighbourSequence = Constants.EMPTY_SEQUENCE;
if (_edgeEnumerator.IsOriginal())
{ // original edge.
if (currentSequence.Length > 1 && currentSequence[currentSequence.Length - 2] == neighbourNeighbour)
{ // this is a u-turn.
continue;
}
if (restrictions != null)
{
neighbourSequence = currentSequence.Append(neighbourNeighbour);
}
}
else
{ // not an original edge, use the sequence.
neighbourSequence = _edgeEnumerator.GetSequence1();
if (currentSequence.Length > 1 && currentSequence[currentSequence.Length - 2] == neighbourSequence[0])
{ // this is a u-turn.
continue;
}
if (restrictions != null)
{
neighbourSequence = currentSequence.Append(neighbourSequence);
}
}
if (restrictions != null)
{ // check restrictions.
if (!restrictions.IsSequenceAllowed(neighbourSequence))
{
continue;
}
}
// build route to neighbour and check if it has been visited already.
var routeToNeighbour = new EdgePath <T>(
neighbourNeighbour, _weightHandler.Add(_current.Weight, neighbourWeight), _edgeEnumerator.IdDirected(), _current);
LinkedEdgePath <T> edgePath = null;
if (!_visits.TryGetValue(_current.Vertex, out edgePath) ||
!edgePath.HasPath(routeToNeighbour))
{ // this vertex has not been visited in this way before.
_heap.Push(routeToNeighbour, _weightHandler.GetMetric(routeToNeighbour.Weight));
}
}
}
return(true);
}
/// <summary>
/// Search backward from one vertex.
/// </summary>
/// <returns></returns>
private void SearchBackward(DirectedDynamicGraph.EdgeEnumerator edgeEnumerator, EdgePath <T> current, IEnumerable <uint[]> restrictions)
{
if (current != null)
{ // there is a next vertex found.
// get the edge enumerator.
var currentSequence = current.GetSequence2(edgeEnumerator);
currentSequence = currentSequence.Append(current.Vertex);
// get neighbours.
edgeEnumerator.MoveTo(current.Vertex);
// add the neighbours to the queue.
while (edgeEnumerator.MoveNext())
{
bool?neighbourDirection;
var neighbourWeight = _weightHandler.GetEdgeWeight(edgeEnumerator.Current, out neighbourDirection);
if (neighbourDirection == null || !neighbourDirection.Value)
{ // the edge is forward, and is to higher or was not contracted at all.
var neighbourNeighbour = edgeEnumerator.Neighbour;
var neighbourSequence = Constants.EMPTY_SEQUENCE;
if (edgeEnumerator.IsOriginal())
{ // original edge.
if (currentSequence.Length > 1 && currentSequence[currentSequence.Length - 2] == neighbourNeighbour)
{ // this is a u-turn.
continue;
}
if (restrictions != null)
{
neighbourSequence = currentSequence.Append(neighbourNeighbour);
}
}
else
{ // not an original edge, use the sequence.
neighbourSequence = edgeEnumerator.GetSequence1();
if (currentSequence.Length > 1 && currentSequence[currentSequence.Length - 2] == neighbourSequence[0])
{ // this is a u-turn.
continue;
}
if (restrictions != null)
{
neighbourSequence = currentSequence.Append(neighbourSequence);
}
}
if (restrictions != null)
{ // check restrictions.
neighbourSequence.Reverse();
if (!restrictions.IsSequenceAllowed(neighbourSequence))
{
continue;
}
}
// build route to neighbour and check if it has been visited already.
var routeToNeighbour = new EdgePath <T>(
neighbourNeighbour, _weightHandler.Add(current.Weight, neighbourWeight), edgeEnumerator.IdDirected(), current);
LinkedEdgePath edgePath = null;
if (!_backwardVisits.TryGetValue(current.Vertex, out edgePath) ||
!edgePath.HasPath(routeToNeighbour))
{ // this vertex has not been visited in this way before.
_backwardQueue.Push(routeToNeighbour, _weightHandler.GetMetric(routeToNeighbour.Weight));
}
}
}
}
}