code: private Set<Integer> obtainCandidates(double[] q) {
          Set<Integer> candidates = new LinkedHashSet<>();
          for (Hash h : hash) {
              BucketEntry bucket = h.get(q);
              if (bucket != null) {
                  int m = bucket.entry.size();
                  for (int i = 0; i < m; i++) {
                      int index = bucket.entry.get(i);
                      candidates.add(index);
                  }
              }
          }
          return candidates;
      }
docs: Obtaining Candidates
  @return Indices of Candidates