/// <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;
}
/// <summary>
/// Remove the edge (u,v) from the graph.
/// If the graph allows parallel edges this remove all occurrences of
/// (u,v).
/// </summary>
/// <param name="u">source vertex</param>
/// <param name="v">target vertex</param>
public override void RemoveEdge(IVertex u, IVertex v)
{
if (u == null)
throw new ArgumentNullException("source vertex");
if (v == null)
throw new ArgumentNullException("targetvertex");
EdgeCollection outEdges = VertexOutEdges[u];
EdgeCollection inEdges = VertexInEdges[v];
// marking edges to remove
EdgeCollection removedEdges = new EdgeCollection();
foreach(IEdge e in outEdges)
{
if (e.Target == v)
removedEdges.Add(e);
}
foreach(IEdge e in inEdges)
{
if (e.Source == u)
removedEdges.Add(e);
}
//removing edges
foreach(IEdge e in removedEdges)
RemoveEdge(e);
}
/// <summary>
/// Merges the temporary circuit with the current circuit
/// </summary>
/// <returns>true if all the graph edges are in the circuit</returns>
protected bool CircuitAugmentation()
{
EdgeCollection newC=new EdgeCollection();
int i,j;
// follow C until w is found
for(i=0;i<Circuit.Count;++i)
{
IEdge e = Circuit[i];
if (e.Source==CurrentVertex)
break;
newC.Add(e);
}
// follow D until w is found again
for(j=0;j<TemporaryCircuit.Count;++j)
{
IEdge e = TemporaryCircuit[j];
newC.Add(e);
OnCircuitEdge(e);
if (e.Target==CurrentVertex)
break;
}
TemporaryCircuit.Clear();
// continue C
for(;i<Circuit.Count;++i)
{
IEdge e = Circuit[i];
newC.Add(e);
}
// set as new circuit
circuit = newC;
// check if contains all edges
if (Circuit.Count == VisitedGraph.EdgesCount)
return true;
return false;
}
/// <summary>
/// Adds temporary edges to the graph to make all vertex even.
/// </summary>
/// <param name="g"></param>
/// <returns></returns>
public EdgeCollection AddTemporaryEdges(IMutableVertexAndEdgeListGraph g)
{
if (g==null)
throw new ArgumentNullException("g");
// first gather odd edges.
VertexCollection oddVertices = AlgoUtility.OddVertices(g);
// check that there are an even number of them
if (oddVertices.Count%2!=0)
throw new Exception("number of odd vertices in not even!");
// add temporary edges to create even edges:
EdgeCollection ec = new EdgeCollection();
bool found,foundbe,foundadjacent;
while (oddVertices.Count > 0)
{
IVertex u = oddVertices[0];
// find adjacent odd vertex.
found = false;
foundadjacent = false;
foreach(IEdge e in g.OutEdges(u))
{
IVertex v = e.Target;
if (v!=u && oddVertices.Contains(v))
{
foundadjacent=true;
// check that v does not have an out-edge towards u
foundbe = false;
foreach(IEdge be in g.OutEdges(v))
{
if (be.Target==u)
{
foundbe = true;
break;
}
}
if (foundbe)
continue;
// add temporary edge
IEdge tempEdge = g.AddEdge(v,u);
// add to collection
ec.Add(tempEdge);
// remove u,v from oddVertices
oddVertices.Remove(u);
oddVertices.Remove(v);
// set u to null
found = true;
break;
}
}
if (!foundadjacent)
{
// pick another vertex
if (oddVertices.Count<2)
throw new Exception("Eulerian trail failure");
IVertex v = oddVertices[1];
IEdge tempEdge = g.AddEdge(u,v);
// add to collection
ec.Add(tempEdge);
// remove u,v from oddVertices
oddVertices.Remove(u);
oddVertices.Remove(v);
// set u to null
found = true;
}
if (!found)
{
oddVertices.Remove(u);
oddVertices.Add(u);
}
}
temporaryEdges = ec;
return ec;
}
public void AddReversedEdges()
{
if (this.Augmented)
{
throw new InvalidOperationException("Graph already augmented");
}
EdgeCollection edges = new EdgeCollection();
IEdgeEnumerator enumerator = this.VisitedGraph.get_Edges().GetEnumerator();
while (enumerator.MoveNext())
{
IEdge edge = enumerator.get_Current();
if (!this.reversedEdges.Contains(edge))
{
IEdge edge2 = this.FindReversedEdge(edge);
if (edge2 != null)
{
this.reversedEdges.set_Item(edge, edge2);
if (!this.reversedEdges.Contains(edge2))
{
this.reversedEdges.set_Item(edge2, edge);
}
}
else
{
edges.Add(edge);
}
}
}
EdgeCollection.Enumerator enumerator2 = edges.GetEnumerator();
while (enumerator2.MoveNext())
{
IEdge edge3 = enumerator2.get_Current();
if (!this.reversedEdges.Contains(edge3))
{
IEdge edge4 = this.FindReversedEdge(edge3);
if (edge4 != null)
{
this.reversedEdges.set_Item(edge3, edge4);
}
else
{
edge4 = this.VisitedGraph.AddEdge(edge3.get_Target(), edge3.get_Source());
this.augmentedEgdes.Add(edge4);
this.reversedEdges.set_Item(edge3, edge4);
this.reversedEdges.set_Item(edge4, edge3);
this.OnReservedEdgeAdded(new EdgeEventArgs(edge4));
}
}
}
this.augmented = true;
}
public void RemoveInEdgeIf(IVertex u, IEdgePredicate pred)
{
if (u == null)
{
throw new ArgumentNullException("vertex u");
}
if (pred == null)
{
throw new ArgumentNullException("predicate");
}
EdgeCollection edges = this.VertexInEdges.get_Item(u);
EdgeCollection edges2 = new EdgeCollection();
EdgeCollection.Enumerator enumerator = edges.GetEnumerator();
while (enumerator.MoveNext())
{
IEdge edge = enumerator.get_Current();
if (pred.Test(edge))
{
edges2.Add(edge);
}
}
EdgeCollection.Enumerator enumerator2 = edges2.GetEnumerator();
while (enumerator2.MoveNext())
{
IEdge e = enumerator2.get_Current();
this.RemoveEdge(e);
}
}
public virtual void RemoveEdge(IVertex u, IVertex v)
{
if (u == null)
{
throw new ArgumentNullException("source vertex");
}
if (v == null)
{
throw new ArgumentNullException("targetvertex");
}
EdgeCollection edges = this.VertexOutEdges.get_Item(u);
if (edges == null)
{
throw new EdgeNotFoundException();
}
EdgeCollection edges2 = new EdgeCollection();
EdgeCollection.Enumerator enumerator = edges.GetEnumerator();
while (enumerator.MoveNext())
{
IEdge edge = enumerator.get_Current();
if (edge.get_Target() == v)
{
edges2.Add(edge);
}
}
EdgeCollection.Enumerator enumerator2 = edges2.GetEnumerator();
while (enumerator2.MoveNext())
{
IEdge edge2 = enumerator2.get_Current();
edges.Remove(edge2);
}
}
/// <summary>
/// Remove all the edges from graph g for which the predicate pred
/// returns true.
/// </summary>
/// <param name="pred">edge predicate</param>
public virtual void RemoveEdgeIf(IEdgePredicate pred)
{
if (pred == null)
throw new ArgumentNullException("predicate");
// marking edge for removal
EdgeCollection removedEdges = new EdgeCollection();
foreach(IEdge e in Edges)
{
if (pred.Test(e))
removedEdges.Add(e);
}
// removing edges
foreach(IEdge e in removedEdges)
RemoveEdge(e);
}
/// <summary>
/// Remove the edge (u,v) from the graph.
/// If the graph allows parallel edges this remove all occurrences of
/// (u,v).
/// </summary>
/// <param name="u">source vertex</param>
/// <param name="v">target vertex</param>
public virtual void RemoveEdge(Vertex u, Vertex v)
{
if (u == null)
throw new ArgumentNullException("u");
if (v == null)
throw new ArgumentNullException("v");
this.version++;
// getting out-edges
EdgeCollection outEdges = this.vertexOutEdges[u];
// marking edges to remove
EdgeCollection removedEdges = new EdgeCollection();
foreach(Edge e in outEdges)
{
if (e.Target == v)
removedEdges.Add(e);
}
//removing out-edges
foreach(Edge e in removedEdges)
outEdges.Remove(e);
removedEdges.Clear();
EdgeCollection inEdges = this.vertexInEdges[v];
foreach(Edge e in inEdges)
{
if (e.Source == u)
removedEdges.Add(e);
}
//removing in-edges
foreach(Edge e in removedEdges)
inEdges.Remove(e);
}
/// <summary>
/// Remove all the out-edges of vertex u for which the predicate pred
/// returns true.
/// </summary>
/// <param name="u">vertex</param>
/// <param name="pred">edge predicate</param>
public void RemoveInEdgeIf(Vertex u, IEdgePredicate pred)
{
if (u==null)
throw new ArgumentNullException("vertex u");
if (pred == null)
throw new ArgumentNullException("predicate");
EdgeCollection edges = this.vertexInEdges[u];
EdgeCollection removedEdges = new EdgeCollection();
foreach(Edge e in edges)
{
if (pred.Test(e))
removedEdges.Add(e);
}
foreach(Edge e in removedEdges)
this.RemoveEdge(e);
}
protected bool CircuitAugmentation()
{
EdgeCollection edges = new EdgeCollection();
int num = 0;
while (num < this.Circuit.Count)
{
IEdge edge = this.Circuit.get_Item(num);
if (edge.get_Source() == this.CurrentVertex)
{
break;
}
edges.Add(edge);
num++;
}
for (int i = 0; i < this.TemporaryCircuit.Count; i++)
{
IEdge e = this.TemporaryCircuit.get_Item(i);
edges.Add(e);
this.OnCircuitEdge(e);
if (e.get_Target() == this.CurrentVertex)
{
break;
}
}
this.TemporaryCircuit.Clear();
while (num < this.Circuit.Count)
{
IEdge edge3 = this.Circuit.get_Item(num);
edges.Add(edge3);
num++;
}
this.circuit = edges;
return (this.Circuit.Count == this.VisitedGraph.get_EdgesCount());
}
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;
}
public EdgeCollection AddTemporaryEdges(IMutableVertexAndEdgeListGraph g)
{
if (g == null)
{
throw new ArgumentNullException("g");
}
VertexCollection vertexs = QuickGraph.Algorithms.AlgoUtility.OddVertices(g);
if ((vertexs.Count % 2) != 0)
{
throw new Exception("number of odd vertices in not even!");
}
EdgeCollection edges = new EdgeCollection();
while (vertexs.Count > 0)
{
IVertex vertex = vertexs.get_Item(0);
bool flag = false;
bool flag3 = false;
IEdgeEnumerator enumerator = g.OutEdges(vertex).GetEnumerator();
while (enumerator.MoveNext())
{
IVertex vertex2 = enumerator.get_Current().get_Target();
if ((vertex2 != vertex) && vertexs.Contains(vertex2))
{
flag3 = true;
bool flag2 = false;
IEdgeEnumerator enumerator2 = g.OutEdges(vertex2).GetEnumerator();
while (enumerator2.MoveNext())
{
if (enumerator2.get_Current().get_Target() == vertex)
{
flag2 = true;
break;
}
}
if (!flag2)
{
IEdge edge3 = g.AddEdge(vertex2, vertex);
edges.Add(edge3);
vertexs.Remove(vertex);
vertexs.Remove(vertex2);
flag = true;
break;
}
}
}
if (!flag3)
{
if (vertexs.Count < 2)
{
throw new Exception("Eulerian trail failure");
}
IVertex vertex3 = vertexs.get_Item(1);
IEdge edge4 = g.AddEdge(vertex, vertex3);
edges.Add(edge4);
vertexs.Remove(vertex);
vertexs.Remove(vertex3);
flag = true;
}
if (!flag)
{
vertexs.Remove(vertex);
vertexs.Add(vertex);
}
}
this.temporaryEdges = edges;
return edges;
}
/// <summary>
/// Augments the <see cref="VisitedGraph"/> with reversed edges.
/// </summary>
/// <exception cref="InvalidOperationException">
/// The graph has already been augmented.
/// </exception>
public void AddReversedEdges()
{
if (this.Augmented)
throw new InvalidOperationException("Graph already augmented");
// step 1, find edges that need reversing
EdgeCollection notReversedEdges = new EdgeCollection();
foreach (IEdge edge in this.VisitedGraph.Edges)
{
// if reversed already found, continue
if (this.reversedEdges.Contains(edge))
continue;
IEdge reversedEdge = this.FindReversedEdge(edge);
if (reversedEdge != null)
{
// setup edge
this.reversedEdges[edge] = reversedEdge;
// setup reversed if needed
if (!this.reversedEdges.Contains(reversedEdge))
this.reversedEdges[reversedEdge] = edge;
continue;
}
// this edge has no reverse
notReversedEdges.Add(edge);
}
// step 2, go over each not reversed edge, add reverse
foreach (IEdge edge in notReversedEdges)
{
if (this.reversedEdges.Contains(edge))
continue;
// already been added
IEdge reversedEdge = this.FindReversedEdge(edge);
if (reversedEdge != null)
{
this.reversedEdges[edge] = reversedEdge;
continue;
}
// need to create one
reversedEdge = this.VisitedGraph.AddEdge(edge.Target, edge.Source);
this.augmentedEgdes.Add(reversedEdge);
this.reversedEdges[edge] = reversedEdge;
this.reversedEdges[reversedEdge] = edge;
this.OnReservedEdgeAdded(new EdgeEventArgs(reversedEdge));
}
this.augmented = true;
}
public virtual void RemoveEdgeIf(IEdgePredicate pred)
{
if (pred == null)
{
throw new ArgumentNullException("predicate");
}
EdgeCollection edges = new EdgeCollection();
VertexEdgesEnumerator enumerator = this.Edges.GetEnumerator();
while (enumerator.MoveNext())
{
IEdge edge = enumerator.get_Current();
if (pred.Test(edge))
{
edges.Add(edge);
}
}
EdgeCollection.Enumerator enumerator2 = edges.GetEnumerator();
while (enumerator2.MoveNext())
{
IEdge e = enumerator2.get_Current();
this.RemoveEdge(e);
}
}
/// <summary>
/// Remove the edge (u,v) from the graph.
/// If the graph allows parallel edges this remove all occurrences of
/// (u,v).
/// </summary>
/// <param name="u">source vertex</param>
/// <param name="v">target vertex</param>
public virtual void RemoveEdge(IVertex u, IVertex v)
{
if (u == null)
throw new ArgumentNullException("source vertex");
if (v == null)
throw new ArgumentNullException("targetvertex");
EdgeCollection edges = VertexOutEdges[u];
if (edges==null)
throw new EdgeNotFoundException();
// marking edges to remove
EdgeCollection removedEdges = new EdgeCollection();
foreach(IEdge e in edges)
{
if (e.Target == v)
removedEdges.Add(e);
}
//removing edges
foreach(IEdge e in removedEdges)
edges.Remove(e);
}
public override void RemoveEdge(IVertex u, IVertex v)
{
if (u == null)
{
throw new ArgumentNullException("source vertex");
}
if (v == null)
{
throw new ArgumentNullException("targetvertex");
}
EdgeCollection edges = base.VertexOutEdges.get_Item(u);
EdgeCollection edges2 = this.VertexInEdges.get_Item(v);
EdgeCollection edges3 = new EdgeCollection();
EdgeCollection.Enumerator enumerator = edges.GetEnumerator();
while (enumerator.MoveNext())
{
IEdge edge = enumerator.get_Current();
if (edge.get_Target() == v)
{
edges3.Add(edge);
}
}
EdgeCollection.Enumerator enumerator2 = edges2.GetEnumerator();
while (enumerator2.MoveNext())
{
IEdge edge2 = enumerator2.get_Current();
if (edge2.get_Source() == u)
{
edges3.Add(edge2);
}
}
EdgeCollection.Enumerator enumerator3 = edges3.GetEnumerator();
while (enumerator3.MoveNext())
{
IEdge e = enumerator3.get_Current();
this.RemoveEdge(e);
}
}
/// <summary>
/// Remove all the out-edges of vertex u for which the predicate pred
/// returns true.
/// </summary>
/// <param name="u">vertex</param>
/// <param name="pred">edge predicate</param>
public virtual void RemoveOutEdgeIf(IVertex u, IEdgePredicate pred)
{
if (u==null)
throw new ArgumentNullException("vertex u");
if (pred == null)
throw new ArgumentNullException("predicate");
EdgeCollection edges = VertexOutEdges[u];
EdgeCollection removedEdges = new EdgeCollection();
foreach(IEdge e in edges)
if (pred.Test(e))
removedEdges.Add(e);
foreach(IEdge e in removedEdges)
RemoveEdge(e);
}
public void ClearVertex(IVertex v)
{
if (v==null)
throw new ArgumentNullException("v");
if (!this.ContainsVertex(v))
throw new ArgumentException("v is not part of the graph");
EdgeCollection edges = new EdgeCollection();
foreach(IEdge e in this.VisitedGraph.OutEdges(v))
edges.Add(e);
foreach(IEdge e in this.VisitedGraph.InEdges(v))
edges.Add(e);
foreach(IEdge e in edges)
{
if (this.VisitedGraph.ContainsEdge(e))
{
RemoveEdge(e);
}
}
}
