public void CheckPredecessorDoubleLineGraph()
{
AdjacencyGraph g = new AdjacencyGraph(true);
IVertex v1 = g.AddVertex();
IVertex v2 = g.AddVertex();
IVertex v3 = g.AddVertex();
IEdge e12 = g.AddEdge(v1,v2);
IEdge e23 = g.AddEdge(v2,v3);
IEdge e13 = g.AddEdge(v1,v3);
EdgeDoubleDictionary weights = DijkstraShortestPathAlgorithm.UnaryWeightsFromEdgeList(g);
DijkstraShortestPathAlgorithm dij = new DijkstraShortestPathAlgorithm(g,weights);
PredecessorRecorderVisitor vis = new PredecessorRecorderVisitor();
dij.RegisterPredecessorRecorderHandlers(vis);
dij.Compute(v1);
EdgeCollection col = vis.Path(v2);
Assert.AreEqual(1,col.Count);
Assert.AreEqual(e12,col[0]);
col = vis.Path(v3);
Assert.AreEqual(1,col.Count);
Assert.AreEqual(e13,col[0]);
}
/// <summary>
/// Computes a set of eulerian trail, starting at <paramref name="s"/>
/// that spans the entire graph.
/// </summary>
/// <remarks>
/// <para>
/// This method computes a set of eulerian trail starting at <paramref name="s"/>
/// that spans the entire graph.The algorithm outline is as follows:
/// </para>
/// <para>
/// The algorithms iterates throught the Eulerian circuit of the augmented
/// graph (the augmented graph is the graph with additional edges to make
/// the number of odd vertices even).
/// </para>
/// <para>
/// If the current edge is not temporary, it is added to the current trail.
/// </para>
/// <para>
/// If the current edge is temporary, the current trail is finished and
/// added to the trail collection. The shortest path between the
/// start vertex <paramref name="s"/> and the target vertex of the
/// temporary edge is then used to start the new trail. This shortest
/// path is computed using the <see cref="BreadthFirstSearchAlgorithm"/>.
/// </para>
/// </remarks>
/// <param name="s">start vertex</param>
/// <returns>eulerian trail set, all starting at s</returns>
/// <exception cref="ArgumentNullException">s is a null reference.</exception>
/// <exception cref="Exception">Eulerian trail not computed yet.</exception>
public EdgeCollectionCollection Trails(IVertex s)
{
if (s==null)
throw new ArgumentNullException("s");
if (this.Circuit.Count==0)
throw new Exception("Circuit is empty");
// find the first edge in the circuit.
int i=0;
for(i=0;i<this.Circuit.Count;++i)
{
IEdge e = this.Circuit[i];
if (TemporaryEdges.Contains(e))
continue;
if (e.Source == s)
break;
}
if (i==this.Circuit.Count)
throw new Exception("Did not find vertex in eulerian trail?");
// create collections
EdgeCollectionCollection trails = new EdgeCollectionCollection();
EdgeCollection trail = new EdgeCollection();
BreadthFirstSearchAlgorithm bfs =
new BreadthFirstSearchAlgorithm(VisitedGraph);
PredecessorRecorderVisitor vis = new PredecessorRecorderVisitor();
bfs.RegisterPredecessorRecorderHandlers(vis);
bfs.Compute(s);
// go throught the edges and build the predecessor table.
int start = i;
for (;i<this.Circuit.Count;++i)
{
IEdge e = this.Circuit[i];
if (TemporaryEdges.Contains(e))
{
// store previous trail and start new one.
if(trail.Count != 0)
trails.Add(trail);
// start new trail
// take the shortest path from the start vertex to
// the target vertex
trail = vis.Path(e.Target);
}
else
trail.Add(e);
}
// starting again on the circuit
for (i=0;i<start;++i)
{
IEdge e = this.Circuit[i];
if (TemporaryEdges.Contains(e))
{
// store previous trail and start new one.
if(trail.Count != 0)
trails.Add(trail);
// start new trail
// take the shortest path from the start vertex to
// the target vertex
trail = vis.Path(e.Target);
}
else
trail.Add(e);
}
// adding the last element
if (trail.Count!=0)
trails.Add(trail);
return trails;
}
public EdgeCollectionCollection Trails(IVertex s)
{
if (s == null)
{
throw new ArgumentNullException("s");
}
if (this.Circuit.Count == 0)
{
throw new Exception("Circuit is empty");
}
int num = 0;
num = 0;
while (num < this.Circuit.Count)
{
IEdge edge = this.Circuit.get_Item(num);
if (!this.TemporaryEdges.Contains(edge) && (edge.get_Source() == s))
{
break;
}
num++;
}
if (num == this.Circuit.Count)
{
throw new Exception("Did not find vertex in eulerian trail?");
}
EdgeCollectionCollection collections = new EdgeCollectionCollection();
EdgeCollection edges = new EdgeCollection();
BreadthFirstSearchAlgorithm algorithm = new BreadthFirstSearchAlgorithm(this.VisitedGraph);
PredecessorRecorderVisitor vis = new PredecessorRecorderVisitor();
algorithm.RegisterPredecessorRecorderHandlers(vis);
algorithm.Compute(s);
int num2 = num;
while (num < this.Circuit.Count)
{
IEdge edge2 = this.Circuit.get_Item(num);
if (this.TemporaryEdges.Contains(edge2))
{
if (edges.Count != 0)
{
collections.Add(edges);
}
edges = vis.Path(edge2.get_Target());
}
else
{
edges.Add(edge2);
}
num++;
}
for (num = 0; num < num2; num++)
{
IEdge edge3 = this.Circuit.get_Item(num);
if (this.TemporaryEdges.Contains(edge3))
{
if (edges.Count != 0)
{
collections.Add(edges);
}
edges = vis.Path(edge3.get_Target());
}
else
{
edges.Add(edge3);
}
}
if (edges.Count != 0)
{
collections.Add(edges);
}
return collections;
}
