natix.SimilaritySearch.NANNI.SearchKNN C# (CSharp) Method

        public override IResult SearchKNN(object q, int K, IResult res)
        {
            // take the distance from q to the centers.
            var dcq_cache = new double[this.clusters.Count];
            var m = this.clusters.Count;
            double min_dist = double.MaxValue;
            for (int centerID = 0; centerID < m; ++centerID) {
                var node = this.clusters [centerID];
                var center = this.DB [node.objID];
                var dcq = this.DB.Dist (center, q);
                dcq_cache [centerID] = dcq;
                res.Push (node.objID, dcq);
                if (dcq < min_dist) {
                    min_dist = dcq;
                }
            }
            this.internal_numdists += m;

            // range queries can be empty at this point
            // var min_dist = res.First.Dist;

            // check for the cells of all the centers
            for (int centerID = 0; centerID < m; ++centerID) {
                var node = this.clusters [centerID];
                var center = this.DB [node.objID];
                var dcq = dcq_cache [centerID];
                var rad = res.CoveringRadius;

                if (dcq > node.cov + rad) { // the elements of the center are not in the query ball
                    continue;
                }

                if (dcq > min_dist + rad + rad) { // the query is in a cell too far from the center.
                    continue;
                }
                // check for the elements in the cell of actual center
                int l = node.dists.Count;
                for (int i = 0; i < l; ++i) {
                    var lower = dcq - node.dists[i];
                    if (lower < 0) {
                        lower = -lower;
                    }
                    if (lower <= rad) {
                        var docID = node.objects [i];
                        var d = this.DB.Dist (this.DB [docID], q);
                        res.Push (docID, d);
                    }
                }
            }
            return res;
        }