KNNQuery<V, D> knnQuery = QueryUtil.getKNNQuery(relationx, getDistanceFunction(), k + 1);
// We need stable indexed DBIDs
ArrayModifiableDBIDs ids = DBIDUtil.newArray(relationx.getDBIDs());
// Sort, so we can do a binary search below.
ids.sort();
// init F,X,Z
Matrix X = new Matrix(ids.size(), 6);
Matrix F = new Matrix(ids.size(), ids.size());
Matrix Y = new Matrix(ids.size(), dimy);