Smrf.NodeXL.ExcelTemplate.VertexDegreeCalculator2.TryCalculateGraphMetrics C# (CSharp) Method

    TryCalculateGraphMetrics
    (
        IGraph graph,
        CalculateGraphMetricsContext calculateGraphMetricsContext,
        out GraphMetricColumn [] graphMetricColumns
    )
    {
        Debug.Assert(graph != null);
        Debug.Assert(calculateGraphMetricsContext != null);
        AssertValid();

        graphMetricColumns = new GraphMetricColumn[0];

        if ( !calculateGraphMetricsContext.ShouldCalculateGraphMetrics(
                GraphMetrics.Degree |
                GraphMetrics.InDegree |
                GraphMetrics.OutDegree
            ) )
        {
            return (true);
        }

        IVertexCollection oVertices = graph.Vertices;
        Int32 iVertices = oVertices.Count;

        // The following lists correspond to vertex worksheet columns.

        List<GraphMetricValueWithID> oInDegreeGraphMetricValues =
            new List<GraphMetricValueWithID>();

        List<GraphMetricValueWithID> oOutDegreeGraphMetricValues =
            new List<GraphMetricValueWithID>();

        List<GraphMetricValueWithID> oDegreeGraphMetricValues =
            new List<GraphMetricValueWithID>();

        // Create a dictionary to keep track of vertex degrees.  The key is the
        // IVertex.ID and the value is a zero-based index into the above lists.

        Dictionary<Int32, Int32> oVertexIDDictionary =
            new Dictionary<Int32, Int32>();

        // Calculate the degrees for each vertex using the
        // VertexDegreeCalculator class in the Algorithms namespace, which
        // knows nothing about Excel.
        //
        // For simplicity, all degree metrics (in-degree, out-degree, and
        // degree) are calculated regardless of whether the graph is directed
        // or undirected.  After all metrics are calculated,
        // FilterGraphMetricColumns() filters out the metrics that don't apply
        // to the graph, based on its directedness.

        Dictionary<Int32, VertexDegrees> oVertexDegreeDictionary;

        if ( !( new Algorithms.VertexDegreeCalculator() ).
            TryCalculateGraphMetrics(graph,
                calculateGraphMetricsContext.BackgroundWorker,
                out oVertexDegreeDictionary) )
        {
            // The user cancelled.

            return (false);
        }

        Int32 iRowID;

        foreach (IVertex oVertex in oVertices)
        {
            if ( !TryGetRowID(oVertex, out iRowID) )
            {
                continue;
            }

            VertexDegrees oVertexDegrees;

            if ( !oVertexDegreeDictionary.TryGetValue(oVertex.ID,
                out oVertexDegrees) )
            {
                Debug.Assert(false);
            }

            oInDegreeGraphMetricValues.Add(new GraphMetricValueWithID(
                iRowID, oVertexDegrees.InDegree) );

            oOutDegreeGraphMetricValues.Add(new GraphMetricValueWithID(
                iRowID, oVertexDegrees.OutDegree) );

            oDegreeGraphMetricValues.Add(new GraphMetricValueWithID(
                iRowID, oVertexDegrees.Degree) );

            Debug.Assert(oInDegreeGraphMetricValues.Count ==
                oOutDegreeGraphMetricValues.Count);

            oVertexIDDictionary.Add(oVertex.ID,
                oInDegreeGraphMetricValues.Count - 1);
        }

        // Figure out which columns to add.

        graphMetricColumns = FilterGraphMetricColumns(graph,
            calculateGraphMetricsContext, oInDegreeGraphMetricValues,
            oOutDegreeGraphMetricValues, oDegreeGraphMetricValues);

        return (true);
    }