public virtual IEdge Successor(IImplicitGraph g, IVertex u)
{
if (g == null)
{
throw new ArgumentNullException("g");
}
if (u == null)
{
throw new ArgumentNullException("u");
}
int num = g.OutDegree(u);
double num2 = 0.0;
IEdgeEnumerator enumerator = g.OutEdges(u).GetEnumerator();
while (enumerator.MoveNext())
{
IEdge edge = enumerator.get_Current();
num2 += this.weights.get_Item(edge);
}
double num3 = this.rnd.NextDouble() * num2;
double num4 = 0.0;
double num5 = 0.0;
IEdgeEnumerator enumerator2 = g.OutEdges(u).GetEnumerator();
while (enumerator2.MoveNext())
{
IEdge edge2 = enumerator2.get_Current();
num5 = num4 + this.weights.get_Item(edge2);
if ((num3 >= num4) && (num3 <= num5))
{
return edge2;
}
num4 = num5;
}
return null;
}
public override TEdge Successor(IImplicitGraph <TVertex, TEdge> g, TVertex u)
{
if (g.IsOutEdgesEmpty(u))
{
return(default(TEdge));
}
// get outweight
double outWeight = GetOutWeight(g, u);
// get succesor
TEdge s = Successor(g, u, this.Rand.NextDouble() * outWeight);
// update probabilities
this.Weights[s] *= this.Factor;
// normalize
foreach (TEdge e in g.OutEdges(u))
{
checked
{
this.Weights[e] /= outWeight;
}
}
return(s);
}
public static void AssertNoOutEdge <TVertex, TEdge>(IImplicitGraph <TVertex, TEdge> graph, TVertex vertex)
where TEdge : IEdge <TVertex>
{
Assert.IsTrue(graph.IsOutEdgesEmpty(vertex));
Assert.AreEqual(0, graph.OutDegree(vertex));
CollectionAssert.IsEmpty(graph.OutEdges(vertex));
}
public override bool TryGetSuccessor(IImplicitGraph <TVertex, TEdge> g, TVertex u, out TEdge successor)
{
if (!g.IsOutEdgesEmpty(u))
{
// get outweight
double outWeight = GetOutWeight(g, u);
// get succesor
TEdge s;
if (this.TryGetSuccessor(g, u, this.Rand.NextDouble() * outWeight, out s))
{
// update probabilities
this.Weights[s] *= this.Factor;
// normalize
foreach (TEdge e in g.OutEdges(u))
{
checked
{
this.Weights[e] /= outWeight;
}
}
successor = s;
return(true);
}
}
successor = default(TEdge);
return(false);
}
/// <inheritdoc />
public override bool TryGetSuccessor(IImplicitGraph <TVertex, TEdge> graph, TVertex vertex, out TEdge successor)
{
if (!graph.IsOutEdgesEmpty(vertex))
{
// Get out weight
double outWeight = GetOutWeight(graph, vertex);
// Get successor
if (TryGetSuccessor(graph, vertex, Rand.NextDouble() * outWeight, out successor))
{
// Update probabilities
Weights[successor] *= Factor;
// Normalize
foreach (TEdge edge in graph.OutEdges(vertex))
{
Weights[edge] /= outWeight;
}
return(true);
}
}
successor = default(TEdge);
return(false);
}
protected bool TryGetSuccessor(IImplicitGraph <TVertex, TEdge> g, TVertex u, double position, out TEdge successor)
{
Contract.Requires(g != null);
Contract.Requires(u != null);
var edges = g.OutEdges(u);
return(TryGetSuccessor(edges, position, out successor));
}
protected double GetOutWeight(IImplicitGraph <TVertex, TEdge> g, TVertex u)
{
Contract.Requires(g != null);
Contract.Requires(u != null);
var edges = g.OutEdges(u);
return(GetWeights(edges));
}
/// <summary>
/// Tries to get the successor of the given <paramref name="vertex"/> in the given <paramref name="graph"/>.
/// </summary>
/// <param name="graph">The graph to search in.</param>
/// <param name="vertex">The vertex.</param>
/// <param name="position">The position.</param>
/// <param name="successor">Found successor, otherwise null.</param>
/// <returns>True if a successor was found, false otherwise.</returns>
protected bool TryGetSuccessor([NotNull] IImplicitGraph <TVertex, TEdge> graph, [NotNull] TVertex vertex, double position, out TEdge successor)
{
Debug.Assert(graph != null);
Debug.Assert(vertex != null);
IEnumerable <TEdge> edges = graph.OutEdges(vertex);
return(TryGetSuccessor(edges, position, out successor));
}
protected double GetOutWeight(IImplicitGraph <TVertex, TEdge> g, TVertex u)
{
double outWeight = 0;
foreach (TEdge e in g.OutEdges(u))
{
outWeight += this.weights[e];
}
return(outWeight);
}
TEdge IImplicitGraph <TVertex, TEdge> .OutEdge(TVertex v, int index)
{
IImplicitGraph <TVertex, TEdge> ithis = this;
Contract.Requires(v != null);
Contract.Requires(ithis.ContainsVertex(v));
Contract.Ensures(Enumerable.Any(ithis.OutEdges(v), e => e.Equals(Contract.Result <TEdge>())));
return(default(TEdge));
}
int IImplicitGraph <TVertex, TEdge> .OutDegree(TVertex v)
{
IImplicitGraph <TVertex, TEdge> ithis = this;
Contract.Requires(v != null);
Contract.Requires(ithis.ContainsVertex(v));
Contract.Ensures(Contract.Result <int>() == Enumerable.Count <TEdge>(ithis.OutEdges(v)));
return(default(int));
}
TEdge IImplicitGraph <TVertex, TEdge> .OutEdge(TVertex v, int index)
{
IImplicitGraph <TVertex, TEdge> ithis = this;
Contract.Requires(v != null);
Contract.Requires(ithis.ContainsVertex(v));
Contract.Requires(index >= 0 && index < ithis.OutDegree(v));
Contract.Ensures(
Enumerable.ElementAt(ithis.OutEdges(v), index).Equals(Contract.Result <TEdge>()));
return(default(TEdge));
}
public IEdge Successor(IImplicitGraph g, IVertex u)
{
if (g == null)
{
throw new ArgumentNullException("g");
}
if (u == null)
{
throw new ArgumentNullException("u");
}
return this.NextState(g.OutDegree(u), g.OutEdges(u));
}
protected static void OutEdges_NullThrows_Test <TVertex, TEdge>(
IImplicitGraph <TVertex, TEdge> graph)
where TVertex : class
where TEdge : IEdge <TVertex>
{
// ReSharper disable ReturnValueOfPureMethodIsNotUsed
// ReSharper disable AssignNullToNotNullAttribute
Assert.Throws <ArgumentNullException>(() => graph.IsOutEdgesEmpty(null));
Assert.Throws <ArgumentNullException>(() => graph.OutDegree(null));
Assert.Throws <ArgumentNullException>(() => graph.OutEdges(null).ToArray());
// ReSharper restore AssignNullToNotNullAttribute
// ReSharper restore ReturnValueOfPureMethodIsNotUsed
}
public static void AssertHasOutEdges <TVertex, TEdge>(
IImplicitGraph <TVertex, TEdge> graph,
TVertex vertex,
IEnumerable <TEdge> edges)
where TEdge : IEdge <TVertex>
{
TEdge[] edgeArray = edges.ToArray();
CollectionAssert.IsNotEmpty(edgeArray);
Assert.IsFalse(graph.IsOutEdgesEmpty(vertex));
Assert.AreEqual(edgeArray.Length, graph.OutDegree(vertex));
CollectionAssert.AreEquivalent(edgeArray, graph.OutEdges(vertex));
}
/// <summary>
/// Selects the next out-<see cref="IEdge"/> in the Markov Chain.
/// </summary>
/// <param name="g">visted graph</param>
/// <param name="u">source vertex</param>
/// <returns>Random next out-edge</returns>
/// <exception cref="ArgumentNullException">
/// <paramref name="g"/> or <paramref name="u"/> is a null reference
/// </exception>
public IEdge Successor(IImplicitGraph g, IVertex u)
{
if (g == null)
{
throw new ArgumentNullException("g");
}
if (u == null)
{
throw new ArgumentNullException("u");
}
return(NextState(g.OutDegree(u), g.OutEdges(u)));
}
/// <summary>
/// Selects the next out-<see cref="IEdge"/> in the Markov Chain.
/// </summary>
/// <param name="g">visted graph</param>
/// <param name="u">source vertex</param>
/// <returns>Random next out-edge</returns>
/// <exception cref="ArgumentNullException">
/// <paramref name="g"/> or <paramref name="u"/> is a null reference
/// </exception>
public virtual IEdge Successor(IImplicitGraph g, IVertex u)
{
if (g == null)
{
throw new ArgumentNullException("g");
}
if (u == null)
{
throw new ArgumentNullException("u");
}
// get number of out-edges
int n = g.OutDegree(u);
// compute out-edge su
double outWeight = 0;
foreach (IEdge e in g.OutEdges(u))
{
outWeight += this.weights[e];
}
// scale and get next edge
double r = rnd.NextDouble() * outWeight;
double pos = 0;
double nextPos = 0;
foreach (IEdge e in g.OutEdges(u))
{
nextPos = pos + this.weights[e];
if (r >= pos && r <= nextPos)
{
return(e);
}
pos = nextPos;
}
return(null);
}
/// <summary>
/// Tries to get the successor of the given <paramref name="vertex"/> in the given <paramref name="graph"/>.
/// </summary>
/// <param name="graph">The graph to search in.</param>
/// <param name="vertex">The vertex.</param>
/// <param name="position">The position.</param>
/// <param name="successor">Found successor, otherwise null.</param>
/// <returns>True if a successor was found, false otherwise.</returns>
protected bool TryGetSuccessor([NotNull] IImplicitGraph <TVertex, TEdge> graph, [NotNull] TVertex vertex, double position, out TEdge successor)
{
if (graph is null)
{
throw new ArgumentNullException(nameof(graph));
}
if (vertex == null)
{
throw new ArgumentNullException(nameof(vertex));
}
IEnumerable <TEdge> edges = graph.OutEdges(vertex);
return(TryGetSuccessor(edges, position, out successor));
}
public static void AssertHasReversedOutEdges <TVertex, TEdge>(
[NotNull] IImplicitGraph <TVertex, SReversedEdge <TVertex, TEdge> > graph,
[NotNull] TVertex vertex,
[NotNull, ItemNotNull] IEnumerable <TEdge> edges)
where TEdge : IEdge <TVertex>
{
TEdge[] edgeArray = edges.ToArray();
CollectionAssert.IsNotEmpty(edgeArray);
Assert.IsFalse(graph.IsOutEdgesEmpty(vertex));
Assert.AreEqual(edgeArray.Length, graph.OutDegree(vertex));
CollectionAssert.AreEquivalent(
edgeArray.Select(edge => new SReversedEdge <TVertex, TEdge>(edge)),
graph.OutEdges(vertex));
}
protected static void OutEdges_Throws_Test <TVertex, TEdge>(
IImplicitGraph <TVertex, TEdge> graph)
where TVertex : IEquatable <TVertex>, new()
where TEdge : IEdge <TVertex>
{
// ReSharper disable ReturnValueOfPureMethodIsNotUsed
// ReSharper disable AssignNullToNotNullAttribute
var vertex = new TVertex();
Assert.Throws <VertexNotFoundException>(() => graph.IsOutEdgesEmpty(vertex));
Assert.Throws <VertexNotFoundException>(() => graph.OutDegree(vertex));
Assert.Throws <VertexNotFoundException>(() => graph.OutEdges(vertex).ToArray());
// ReSharper restore AssignNullToNotNullAttribute
// ReSharper restore ReturnValueOfPureMethodIsNotUsed
}
protected TEdge Successor(IImplicitGraph <TVertex, TEdge> g, TVertex u, double position)
{
double pos = 0;
double nextPos = 0;
foreach (TEdge e in g.OutEdges(u))
{
nextPos = pos + this.weights[e];
if (position >= pos && position <= nextPos)
{
return(e);
}
pos = nextPos;
}
return(default(TEdge));
}
protected static void OutEdges_Throws_Test(
[NotNull] GraphData <int, Edge <int> > data,
[NotNull] IImplicitGraph <int, Edge <int> > graph)
{
// ReSharper disable ReturnValueOfPureMethodIsNotUsed
data.CheckCalls(0);
data.ShouldReturnValue = false;
Assert.Throws <VertexNotFoundException>(() => graph.IsOutEdgesEmpty(1));
data.CheckCalls(1);
Assert.Throws <VertexNotFoundException>(() => graph.OutDegree(1));
data.CheckCalls(1);
Assert.Throws <VertexNotFoundException>(() => graph.OutEdges(1));
data.CheckCalls(1);
// ReSharper restore ReturnValueOfPureMethodIsNotUsed
}
public IEnumerable <Edge> OutEdges(Vertex v)
{
return(_impl.OutEdges(v));
}
protected double GetOutWeight(IImplicitGraph <TVertex, TEdge> g, TVertex u)
{
var edges = g.OutEdges(u);
return(GetWeights(edges));
}
/// <summary>
/// Gets the weight of the given <paramref name="vertex"/> out edges.
/// </summary>
/// <param name="graph">Graph to consider.</param>
/// <param name="vertex">Vertex to get out weight.</param>
/// <returns>Out weight.</returns>
protected double GetOutWeight([NotNull] IImplicitGraph <TVertex, TEdge> graph, [NotNull] TVertex vertex)
{
IEnumerable <TEdge> edges = graph.OutEdges(vertex);
return(GetWeights(edges));
}
/// <summary>
/// Selects the next out-<see cref="IEdge"/> in the Markov Chain.
/// </summary>
/// <param name="g">visted graph</param>
/// <param name="u">source vertex</param>
/// <returns>Random next out-edge</returns>
/// <exception cref="ArgumentNullException">
/// <paramref name="g"/> or <paramref name="u"/> is a null reference
/// </exception>
public virtual IEdge Successor(IImplicitGraph g, IVertex u)
{
if (g==null)
throw new ArgumentNullException("g");
if (u==null)
throw new ArgumentNullException("u");
// get number of out-edges
int n = g.OutDegree(u);
// compute out-edge su
double outWeight = 0;
foreach(IEdge e in g.OutEdges(u))
{
outWeight+=this.weights[e];
}
// scale and get next edge
double r = rnd.NextDouble() * outWeight;
double pos = 0;
double nextPos = 0;
foreach(IEdge e in g.OutEdges(u))
{
nextPos = pos+this.weights[e];
if (r>=pos && r<=nextPos)
return e;
pos = nextPos;
}
return null;
}
