Analyzer.OverallReciprocationCalculator.CountVertexPairsWithBothDirectedEdges C# (CSharp) Method

        CountVertexPairsWithBothDirectedEdges
        (
            IGraph oGraph,
            HashSet<Int64> oVertexIDPairsOrdered
        )
        {
            Debug.Assert(oGraph != null);
            Debug.Assert(oGraph.Directedness == GraphDirectedness.Directed);
            Debug.Assert(oVertexIDPairsOrdered != null);
            
            // Note that each vertex pair connected with both directed edges will
            // get counted twice here.

            Int32 iVertexPairsWithBothDirectedEdges = 0;

            foreach (Int64 oVertexIDPairOrdered in oVertexIDPairsOrdered)
            {
                // Check whether the HashSet contains a vertex pair with the order
                // of the vertex IDs reversed.

                Int32 iVertex1ID, iVertex2ID;

                CollectionUtil.ParseDictionaryKey(oVertexIDPairOrdered,
                    out iVertex1ID, out iVertex2ID);

                if (oVertexIDPairsOrdered.Contains(
                    CollectionUtil.GetDictionaryKey(
                        iVertex2ID, iVertex1ID, true)))
                {
                    iVertexPairsWithBothDirectedEdges++;
                }
            }

            Debug.Assert(iVertexPairsWithBothDirectedEdges % 2 == 0);

            return (iVertexPairsWithBothDirectedEdges / 2);
        }