public void GetDependencyGraph()
{
DirectedGraph <Type> graph = reflector.GetDependencyGraph();
Assert.IsNotNull(graph);
Assert.AreEqual(19, graph.Count());
DirectedGraph <Type> .Edges edges = graph.EdgesFor(typeof(SampleCodeBase.IFoo));
Assert.IsNotNull(edges);
Assert.IsNotNull(edges.inBound);
Assert.IsNotNull(edges.outBound);
Assert.AreEqual(1, edges.inBound.Count());
Assert.AreEqual(typeof(SampleCodeBase.ImplementsIFoo), edges.inBound.First());
Assert.AreEqual(0, edges.outBound.Count());
}
/// <summary>
/// PageRank computes a ranking of the nodes in the graph G based on
/// the structure of the incoming links.It was originally designed as
/// an algorithm to rank web pages.
/// </summary>
/// <typeparam name="T"></typeparam>
/// <description></description>
/// <param name="graph"></param>
/// <description></description>
/// <param name="alpha"></param>
/// <description></description>
/// <param name="maxItteration"></param>
/// <description></description>
/// <param name="tol"></param>
/// <description></description>
/// <param name="nstart"></param>
/// <description></description>
/// <param name="personalization"></param>
/// <description></description>
/// <param name="dangling"></param>
/// <description></description>
/// <returns>rankVector</returns>
public Dictionary <T, double> Rank <T>(DirectedGraph <T> graph, double alpha = 0.85,
double maxItteration = 100, double tol = 1.0e-6,
Dictionary <T, double> nstart = null, Dictionary <T, double> personalization = null,
Dictionary <T, double> dangling = null)
{
Dictionary <T, double> _rankVector = null;
DirectedGraph <T> dGraph;
// Boundary condition
// Check if graph is empty then return with empty page rank dictionary
if (graph.IsEmpty)
{
return(null);
}
if (!graph.IsDirected)
{
// Convert to directed graph
//dgraph = Graph.BuildDirectedGraph(graph);
}
else
{
dGraph = graph;
}
//Create a copy in (right) stochastic form
//stochasti matrix has a square matrix that have summation of each row is 1.
DirectedGraph <T> sGraph = GraphUtils.ToStochastic(graph);
int N = sGraph.Count();
Dictionary <GraphNode <T>, double> _x = new Dictionary <GraphNode <T>, double>();
Dictionary <GraphNode <T>, double> _p = new Dictionary <GraphNode <T>, double>();
Dictionary <GraphNode <T>, double> _dangling_weights = new Dictionary <GraphNode <T>, double>();
// Choose fixed starting vector if not given
if (nstart == null)
{
_x = sGraph.Nodes.ToDictionary(item => item as GraphNode <T>, val => 1.0 / N);
}
else
{
// Normalized nstart vector
double _nSum = (double)nstart.Sum(node => node.Value);
_p = nstart.ToDictionary(item => item.Key as GraphNode <T>, item => item.Value / _nSum);
}
if (personalization == null)
{
_p = sGraph.Nodes.ToDictionary(item => item as GraphNode <T>, val => 1.0 / N);
}
else
{
// Normalized personalization vector
double _pSum = (double)personalization.Sum(node => node.Value);
_p = personalization.ToDictionary(item => item.Key as GraphNode <T>, item => item.Value / _pSum);
}
if (dangling == null)
{
_dangling_weights = sGraph.Nodes.ToDictionary(item => item as GraphNode <T>, val => 1.0 / N);
}
else
{
// Normalized personalization vector
double _dSum = (double)dangling.Sum(node => node.Value);
_dangling_weights = dangling.ToDictionary(item => item.Key as GraphNode <T>, item => item.Value / _dSum);
}
// Get the dangling nodes of graph
List <GraphNode <T> > _danglingNodes = sGraph.DanglingNodes;
Dictionary <GraphNode <T>, double> _xLast = _x;
do
{
//copy the the older rank value
_xLast = _x.ToDictionary(item => item.Key, item => item.Value);
_x = _xLast.ToDictionary(item => item.Key, value => 0.0);
//calculate the dangling sum
var danglesum = alpha * _xLast.Where(x => _danglingNodes.Any(item => x.Key == item)).Sum(v => v.Value);
foreach (GraphNode <T> page in _x.Keys.ToList())
{
var nbrs = sGraph[page];
foreach (var nbr in nbrs)
{
var xn = _xLast[page];
var we = sGraph[page, nbr.GraphNode as GraphNode <T> ];
_x[nbr.GraphNode as GraphNode <T> ] += alpha * xn * we;
}
var _dnglWeight = _dangling_weights.ContainsKey(page) ? _dangling_weights[page] : 0;
var _perWeight = _dangling_weights.ContainsKey(page) ? _dangling_weights[page] : 0;
_x[page] += danglesum * _dnglWeight + (1.0 - alpha) * _perWeight;
}
//check convergence, l1 norm
double err = 0.0;
foreach (var node in _x.Keys.ToList())
{
err += Math.Abs(_x[node] - _xLast[node]);
}
if (err < N * tol)
{
_rankVector = _x.ToDictionary(item => item.Key.Value, item => item.Value);
break;
}
} while (maxItteration-- > 0);
return(_rankVector);
}
/// <summary>
/// PageRank computes a ranking of the nodes in the graph G based on
/// the structure of the incoming links.It was originally designed as
/// an algorithm to rank web pages.
/// </summary>
/// <typeparam name="T"></typeparam>
/// <description></description>
/// <param name="graph"></param>
/// <description></description>
/// <param name="alpha"></param>
/// <description></description>
/// <param name="maxItteration"></param>
/// <description></description>
/// <param name="epsilon"></param>
/// <description></description>
/// <param name="nstart"></param>
/// <description></description>
/// <param name="personalization"></param>
/// <description></description>
/// <param name="dangling"></param>
/// <description></description>
/// <returns>rankVector</returns>
public Dictionary <T, double> Rank <T>(Graph <T> graph, double alpha = 0.85,
double maxItteration = 100, double epsilon = 1.0e-6,
Dictionary <T, double> nstart = null, Dictionary <T, double> personalization = null,
Dictionary <T, double> dangling = null)
{
Dictionary <T, double> rankVector = null;
var dgraph = new DirectedGraph <T>();
// Boundary condition
// Check if graph is empty then return with empty page rank dictionary
if (graph.IsEmpty)
{
return(null);
}
if (!graph.IsDirected)
{
// Convert to directed graph
dgraph = GraphUtils.BuildDirectedGraph(graph);
}
else
{
dgraph = graph as DirectedGraph <T>;
}
//Create a copy in (right) stochastic form
//stochasti matrix has a square matrix that have summation of each row is 1.
DirectedGraph <T> sGraph = GraphUtils.ToStochastic(graph);
int N = sGraph.Count();
var x = new Dictionary <GraphNode <T>, double>();
var p = new Dictionary <GraphNode <T>, double>();
var danglingWeights = new Dictionary <GraphNode <T>, double>();
// Choose fixed starting vector if not given
if (nstart == null)
{
x = sGraph.Nodes.ToDictionary(item => item as GraphNode <T>, val => 1.0 / N);
}
else
{
// Normalized nstart vector
double _nSum = (double)nstart.Sum(node => node.Value);
p = nstart.ToDictionary(item => item.Key as GraphNode <T>, item => item.Value / _nSum);
}
if (personalization == null)
{
p = sGraph.Nodes.ToDictionary(item => item as GraphNode <T>, val => 1.0 / N);
}
else
{
// Normalized personalization vector
double _pSum = (double)personalization.Sum(node => node.Value);
p = personalization.ToDictionary(item => item.Key as GraphNode <T>, item => item.Value / _pSum);
}
if (dangling == null)
{
danglingWeights = sGraph.Nodes.ToDictionary(item => item as GraphNode <T>, val => 1.0 / N);
}
else
{
// Normalized personalization vector
double _dSum = (double)dangling.Sum(node => node.Value);
danglingWeights = dangling.ToDictionary(item => item.Key as GraphNode <T>, item => item.Value / _dSum);
}
// Get the dangling nodes of graph
var danglingNodes = sGraph.DanglingNodes;
var xLast = x;
var lastErr = double.MaxValue;
do
{
//copy the the older rank value
xLast = x.ToDictionary(item => item.Key, item => item.Value);
x = xLast.ToDictionary(item => item.Key, value => 0.0);
//calculate the dangling sum
var danglesum = alpha * xLast.Where(v => danglingNodes.Any(item => v.Key == item)).Sum(v => v.Value);
foreach (var page in x.Keys.ToList())
{
var nbrs = sGraph[page];
foreach (var nbr in nbrs)
{
var xn = xLast[page];
var we = sGraph[page, nbr.GraphNode as GraphNode <T> ];
x[nbr.GraphNode as GraphNode <T> ] += alpha * xn * we;
}
var dnglWeight = danglingWeights.ContainsKey(page) ? danglingWeights[page] : 0;
var perWeight = danglingWeights.ContainsKey(page) ? danglingWeights[page] : 0;
x[page] += danglesum * dnglWeight + (1.0 - alpha) * perWeight;
}
//check convergence, l1 norm
double err = 0.0;
foreach (var node in x.Keys.ToList())
{
err += Math.Abs(x[node] - xLast[node]);
}
if (err < lastErr)
{
rankVector = x.ToDictionary(item => item.Key.Value, item => item.Value);
lastErr = err;
}
if (err < N * epsilon)
{
break;
}
} while (maxItteration-- > 0);
return(rankVector);
}
