/// <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);
}
List <uint> s = null;
while (true)
{
if (path.IsOriginal(enumerator))
{ // current segment is original.
if (s == null)
{
s = new List <uint>();
}
s.Add(path.From.Vertex);
if (s.Count < n && path.From.From != null)
{ // we need more vertices and there are some more available.
path = path.From;
}
else
{ // we have enough.
var result = s.ToArray();
result.Reverse();
return(result);
}
}
else
{ // not an original edge, just return the start sequence.
if (s != null)
{
var s2 = enumerator.GetSequence2();
var result = new uint[s.Count + s2.Length];
for (var i = 0; i < s.Count; i++)
{
result[result.Length - 1 - i] = s[i];
}
for (var i = 0; i < s2.Length; i++)
{
result[i] = s2[i];
}
return(result);
}
return(enumerator.GetSequence2());
}
}
}
/// <summary>
/// Expands the last edge in the given edge path.
/// </summary>
private static EdgePath <T> ExpandLast <T>(this EdgePath <T> edgePath, DirectedDynamicGraph.EdgeEnumerator enumerator, WeightHandler <T> weightHandler, bool direction)
where T : struct
{
if (edgePath.Edge != Constants.NO_EDGE &&
edgePath.From != null &&
edgePath.From.Vertex != Constants.NO_VERTEX)
{
enumerator.MoveToEdge(edgePath.Edge);
var contractedId = enumerator.GetContracted();
if (contractedId.HasValue)
{ // there is a contracted vertex here!
// get source/target sequences.
var sequence1 = enumerator.GetSequence1();
sequence1.Reverse();
var sequence2 = enumerator.GetSequence2();
if (enumerator.Neighbour != edgePath.Vertex)
{
sequence1.Reverse();
sequence2.Reverse();
var t = sequence2;
sequence2 = sequence1;
sequence1 = t;
}
// move to the first edge (contracted -> from vertex) and keep details.
bool?localDirection;
if (!enumerator.MoveToEdge(contractedId.Value, edgePath.From.Vertex, sequence1, weightHandler, !direction))
{
throw new Exception(string.Format("Edge between {0} -> {1} with sequence {2} could not be found.",
contractedId.Value, edgePath.From.Vertex, sequence1.ToStringSafe()));
}
var edge1 = enumerator.IdDirected();
var weight1 = weightHandler.GetEdgeWeight(enumerator.Current, out localDirection);
// move to the second edge (contracted -> to vertex) and keep details.
if (!enumerator.MoveToEdge(contractedId.Value, edgePath.Vertex, sequence2, weightHandler, direction))
{
throw new Exception(string.Format("Edge between {0} -> {1} with sequence {2} could not be found.",
contractedId.Value, edgePath.Vertex, sequence2.ToStringSafe()));
}
var weight2 = weightHandler.GetEdgeWeight(enumerator.Current, out localDirection);
var edge2 = enumerator.IdDirected();
var contractedPath = new EdgePath <T>(contractedId.Value, weightHandler.Add(edgePath.From.Weight, weight1), edge1, edgePath.From);
contractedPath = contractedPath.ExpandLast(enumerator, weightHandler, direction);
return((new EdgePath <T>(edgePath.Vertex, edgePath.Weight, edge2, contractedPath)).ExpandLast(enumerator, weightHandler, direction));
}
}
return(edgePath);
}
/// <summary>
/// Expands the last edge in the given edge path.
/// </summary>
private static EdgePath <T> ExpandLast <T>(this EdgePath <T> edgePath, DirectedDynamicGraph.EdgeEnumerator enumerator, WeightHandler <T> weightHandler)
where T : struct
{
bool?direction;
if (edgePath.Edge != Constants.NO_EDGE &&
edgePath.From != null &&
edgePath.From.Vertex != Constants.NO_VERTEX)
{
enumerator.MoveToEdge(edgePath.Edge);
var contractedId = enumerator.GetContracted();
if (contractedId.HasValue)
{ // there is a contracted vertex here!
// get source/target sequences.
var sequence1 = enumerator.GetSequence1();
sequence1.Reverse();
var sequence2 = enumerator.GetSequence2();
// move to the first edge (contracted -> from vertex) and keep details.
enumerator.MoveToEdge(contractedId.Value, edgePath.From.Vertex, sequence1);
var edge1 = enumerator.IdDirected();
var weight1 = weightHandler.GetEdgeWeight(enumerator.Current, out direction);
// move to the second edge (contracted -> to vertex) and keep details.
enumerator.MoveToEdge(contractedId.Value, edgePath.Vertex, sequence2);
var weight2 = weightHandler.GetEdgeWeight(enumerator.Current, out direction);
var edge2 = enumerator.IdDirected();
if (edgePath.Edge > 0)
{
var contractedPath = new EdgePath <T>(contractedId.Value, weightHandler.Add(edgePath.From.Weight, weight1), -edge1, edgePath.From);
contractedPath = contractedPath.ExpandLast(enumerator, weightHandler);
return((new EdgePath <T>(edgePath.Vertex, edgePath.Weight, edge2, contractedPath)).ExpandLast(enumerator, weightHandler));
}
else
{
var contractedPath = new EdgePath <T>(contractedId.Value, weightHandler.Add(edgePath.From.Weight, weight1), edge1, edgePath.From);
contractedPath = contractedPath.ExpandLast(enumerator, weightHandler);
return((new EdgePath <T>(edgePath.Vertex, edgePath.Weight, -edge2, contractedPath)).ExpandLast(enumerator, weightHandler));
}
}
}
return(edgePath);
}
