Why Recall@K is equal to zero about hdc.caffe HOT 1 OPEN

I am very confused that labels of query images are indices of list. In the script test_cars196.py, i get labels of query images from test_8131.txt instead of test_label.dat. Then the results of recall@K seem normal.
Using the model author trained, Recall @k on CARS196 test set as follow

  | Recall@K(%)
  | 1 | 2 | 4 | 8 | 16 | 32
HDC+Contrastive-1-128 | 48.1 | 60.9 | 72.4 | 82.1 | 89.7 | 94.4
HDC+Contrastive-2-128 | 59.0 | 71.3 | 81.0 | 87.7 | 93.0 | 96.2
HDC+Contrastive-3-128 | 65.9 | 77.1 | 85.9 | 92.0 | 95.6 | 97.7
HDC+Contrastive-384 | 72.1 | 82.3 | 88.9 | 93.5 | 96.6 | 98.3

there is little difference.

from hdc.caffe.