/// <summary>
/// Contracts the given vertex.
/// </summary>
private void Contract(uint vertex)
{
// get and keep edges.
var enumerator = _graph.GetEdgeEnumerator(vertex);
var edges = new List <DynamicEdge>(enumerator);
// check if this vertex has a potential restrictions.
var hasRestrictions = _restrictionFlags[vertex];
// loop over all edge-pairs once.
for (var j = 1; j < edges.Count; j++)
{
var edge1 = edges[j];
var edge1Sequence2 = edges[j].GetSequence2();
if (edge1Sequence2.Length == 0)
{
edge1Sequence2 = new uint[] { vertex };
}
bool?edge1Direction;
var edge1Weight = _weightHandler.GetEdgeWeight(edge1, out edge1Direction);
var edge1CanMoveForward = edge1Direction == null || edge1Direction.Value;
var edge1CanMoveBackward = edge1Direction == null || !edge1Direction.Value;
// figure out what witness paths to calculate.
var forwardWitnesses = new EdgePath <T> [j];
var backwardWitnesses = new EdgePath <T> [j];
var targets = new List <uint>(j);
var targetWeights = new List <T>(j);
for (var k = 0; k < j; k++)
{
var edge2 = edges[k];
bool?edge2Direction;
var edge2Weight = _weightHandler.GetEdgeWeight(edge2, out edge2Direction);
var edge2CanMoveForward = edge2Direction == null || edge2Direction.Value;
var edge2CanMoveBackward = edge2Direction == null || !edge2Direction.Value;
// use witness flags to represent impossible routes.
if (!(edge1CanMoveBackward && edge2CanMoveForward))
{
forwardWitnesses[k] = new EdgePath <T>();
}
if (!(edge1CanMoveForward && edge2CanMoveBackward))
{
backwardWitnesses[k] = new EdgePath <T>();
}
targets.Add(edge2.Neighbour);
if (hasRestrictions)
{
targetWeights.Add(_weightHandler.Infinite);
}
else
{
targetWeights.Add(_weightHandler.Add(edge1Weight, edge2Weight));
}
}
// calculate all witness paths.
_witnessCalculator.Calculate(_graph, _getRestrictions, edge1.Neighbour, targets, targetWeights, ref forwardWitnesses,
ref backwardWitnesses, Constants.NO_VERTEX);
// get all sequences where needed.
var s1forward = new uint[forwardWitnesses.Length][];
var s2forward = new uint[forwardWitnesses.Length][];
var s1backward = new uint[backwardWitnesses.Length][];
var s2backward = new uint[backwardWitnesses.Length][];
for (var k = 0; k < j; k++)
{
var edge2Sequence2 = edges[k].GetSequence2();
if (edge2Sequence2.Length == 0)
{
edge2Sequence2 = new uint[] { vertex };
}
if (forwardWitnesses[k].HasVertex(vertex))
{ // get forward sequences.
s1forward[k] = forwardWitnesses[k].GetSequence1(enumerator, 1);
s2forward[k] = forwardWitnesses[k].GetSequence2(enumerator, 1);
if (!s1forward[k].IsSequenceIdentical(edge1Sequence2) ||
!s2forward[k].IsSequenceIdentical(edge2Sequence2))
{ // start and end sequences of shortest paths need to match.
s1forward[k] = null;
s2forward[k] = null;
}
}
if (backwardWitnesses[k].HasVertex(vertex))
{ // get backward sequences.
s1backward[k] = backwardWitnesses[k].GetSequence1(enumerator, 1);
s2backward[k] = backwardWitnesses[k].GetSequence2(enumerator, 1);
if (!s1backward[k].IsSequenceIdentical(edge1Sequence2) ||
!s2backward[k].IsSequenceIdentical(edge2Sequence2))
{ // start and end sequences of shortest paths need to match.
s1backward[k] = null;
s2backward[k] = null;
}
}
}
// add contracted edges if needed.
for (var k = 0; k < j; k++)
{
var edge2 = edges[k];
if (edge1.Neighbour == edge2.Neighbour)
{ // do not try to add a shortcut between identical vertices.
continue;
}
//if (s1forward[k] != null && s1backward[k] != null &&
// System.Math.Abs(_weightHandler.GetMetric(forwardWitnesses[k].Weight) - _weightHandler.GetMetric(backwardWitnesses[k].Weight)) < E)
//{ // paths in both direction are possible and with the same weight, add just one edge in each direction.
// s1backward[k].Reverse();
// s2backward[k].Reverse();
// _weightHandler.AddOrUpdateEdge(_graph, edge1.Neighbour, edge2.Neighbour, vertex, null,
// forwardWitnesses[k].Weight, s1forward[k], s2forward[k]);
// //_graph.AddOrUpdateEdge(edge1.Neighbour, edge2.Neighbour,
// // forwardWitnesses[k].Weight, null, vertex, s1forward[k], s2forward[k]);
// _weightHandler.AddOrUpdateEdge(_graph, edge2.Neighbour, edge1.Neighbour, vertex, null,
// backwardWitnesses[k].Weight, s2backward[k], s1backward[k]);
// //_graph.AddOrUpdateEdge(edge2.Neighbour, edge1.Neighbour,
// // backwardWitnesses[k].Weight, null, vertex, s2backward[k], s1backward[k]);
//}
//else
//{ // add two edge per direction.
if (s1forward[k] != null)
{ // add forward edge.
_weightHandler.AddOrUpdateEdge(_graph, edge1.Neighbour, edge2.Neighbour, vertex, true,
forwardWitnesses[k].Weight, s1forward[k], s2forward[k]);
//_graph.AddOrUpdateEdge(edge1.Neighbour, edge2.Neighbour,
// forwardWitnesses[k].Weight, true, vertex, s1forward[k], s2forward[k]);
s1forward[k].Reverse();
s2forward[k].Reverse();
_weightHandler.AddOrUpdateEdge(_graph, edge2.Neighbour, edge1.Neighbour, vertex, false,
forwardWitnesses[k].Weight, s2forward[k], s1forward[k]);
//_graph.AddOrUpdateEdge(edge2.Neighbour, edge1.Neighbour,
// forwardWitnesses[k].Weight, false, vertex, s2forward[k], s1forward[k]);
}
if (s1backward[k] != null)
{ // add forward edge.
_weightHandler.AddOrUpdateEdge(_graph, edge1.Neighbour, edge2.Neighbour, vertex, false,
backwardWitnesses[k].Weight, s1backward[k], s2backward[k]);
//_graph.AddOrUpdateEdge(edge1.Neighbour, edge2.Neighbour,
// backwardWitnesses[k].Weight, false, vertex, s2backward[k], s1backward[k]);
s1backward[k].Reverse();
s2backward[k].Reverse();
_weightHandler.AddOrUpdateEdge(_graph, edge2.Neighbour, edge1.Neighbour, vertex, true,
backwardWitnesses[k].Weight, s2backward[k], s1backward[k]);
//_graph.AddOrUpdateEdge(edge2.Neighbour, edge1.Neighbour,
// backwardWitnesses[k].Weight, true, vertex, s1backward[k], s2backward[k]);
}
//}
}
}
// remove 'downward' edge to vertex.
var i = 0;
while (i < edges.Count)
{
_graph.RemoveEdge(edges[i].Neighbour, vertex);
if (_contractedFlags[edges[i].Neighbour])
{ // neighbour was already contracted, remove 'downward' edge and exclude it.
_graph.RemoveEdge(vertex, edges[i].Neighbour);
edges.RemoveAt(i);
}
else
{ // move to next edge.
i++;
}
}
_contractedFlags[vertex] = true;
_priorityCalculator.NotifyContracted(vertex);
}
/// <summary>
/// Contracts the given vertex.
/// </summary>
private void Contract(uint vertex)
{
// get and keep edges.
var edges = new List <MetaEdge>(_graph.GetEdgeEnumerator(vertex));
// remove 'downward' edge to vertex.
var i = 0;
while (i < edges.Count)
{
_graph.RemoveEdge(edges[i].Neighbour, vertex);
if (_contractedFlags[edges[i].Neighbour])
{ // neighbour was already contracted, remove 'downward' edge and exclude it.
_graph.RemoveEdge(vertex, edges[i].Neighbour);
edges.RemoveAt(i);
}
else
{ // move to next edge.
i++;
}
}
// check for a restriction, if vertex is restricted don't add shortcuts.
if (_restrictions != null &&
_restrictions.Update(vertex))
{
if (_restrictions.Restricts(vertex))
{
return;
}
}
// loop over all edge-pairs once.
for (var j = 1; j < edges.Count; j++)
{
var edge1 = edges[j];
bool?edge1Direction;
var edge1Weight = _weightHandler.GetEdgeWeight(edge1, out edge1Direction);
var edge1CanMoveForward = edge1Direction == null || edge1Direction.Value;
var edge1CanMoveBackward = edge1Direction == null || !edge1Direction.Value;
// figure out what witness paths to calculate.
var forwardWitnesses = new bool[j];
var backwardWitnesses = new bool[j];
var targets = new List <uint>(j);
var targetWeights = new List <T>(j);
var targetMetrics = new List <float>(j);
for (var k = 0; k < j; k++)
{
var edge2 = edges[k];
bool?edge2Direction;
var edge2Weight = _weightHandler.GetEdgeWeight(edge2, out edge2Direction);
var edge2CanMoveForward = edge2Direction == null || edge2Direction.Value;
var edge2CanMoveBackward = edge2Direction == null || !edge2Direction.Value;
// use witness flags to represent impossible routes.
forwardWitnesses[k] = !(edge1CanMoveBackward && edge2CanMoveForward);
backwardWitnesses[k] = !(edge1CanMoveForward && edge2CanMoveBackward);
targets.Add(edge2.Neighbour);
var totalWeight = _weightHandler.Add(edge1Weight, edge2Weight);
targetWeights.Add(totalWeight);
targetMetrics.Add(_weightHandler.GetMetric(totalWeight));
}
// calculate all witness paths.
_witnessCalculator.Calculate(_graph.Graph, edge1.Neighbour, targets, targetMetrics, ref forwardWitnesses,
ref backwardWitnesses, vertex);
// add contracted edges if needed.
for (var k = 0; k < j; k++)
{
var edge2 = edges[k];
if (edge1.Neighbour == edge2.Neighbour)
{ // do not try to add a shortcut between identical vertices.
continue;
}
if (!forwardWitnesses[k] && !backwardWitnesses[k])
{ // add bidirectional edge.
_weightHandler.AddOrUpdateEdge(_graph, edge1.Neighbour, edge2.Neighbour,
vertex, null, targetWeights[k]);
//_graph.AddOrUpdateEdge(edge1.Neighbour, edge2.Neighbour,
// targetWeights[k], null, vertex);
_weightHandler.AddOrUpdateEdge(_graph, edge2.Neighbour, edge1.Neighbour,
vertex, null, targetWeights[k]);
//_graph.AddOrUpdateEdge(edge2.Neighbour, edge1.Neighbour,
// targetWeights[k], null, vertex);
}
else if (!forwardWitnesses[k])
{ // add forward edge.
_weightHandler.AddOrUpdateEdge(_graph, edge1.Neighbour, edge2.Neighbour,
vertex, true, targetWeights[k]);
//_graph.AddOrUpdateEdge(edge1.Neighbour, edge2.Neighbour,
// targetWeights[k], true, vertex);
_weightHandler.AddOrUpdateEdge(_graph, edge2.Neighbour, edge1.Neighbour,
vertex, false, targetWeights[k]);
//_graph.AddOrUpdateEdge(edge2.Neighbour, edge1.Neighbour,
// targetWeights[k], false, vertex);
}
else if (!backwardWitnesses[k])
{ // add forward edge.
_weightHandler.AddOrUpdateEdge(_graph, edge1.Neighbour, edge2.Neighbour,
vertex, false, targetWeights[k]);
//_graph.AddOrUpdateEdge(edge1.Neighbour, edge2.Neighbour,
// targetWeights[k], false, vertex);
_weightHandler.AddOrUpdateEdge(_graph, edge2.Neighbour, edge1.Neighbour,
vertex, true, targetWeights[k]);
//_graph.AddOrUpdateEdge(edge2.Neighbour, edge1.Neighbour,
// targetWeights[k], true, vertex);
}
}
}
_contractedFlags[vertex] = true;
_priorityCalculator.NotifyContracted(vertex);
}